THD Hotplate Attenuator (8 Ohm)

Very Easy to use....just connect the speaker output on the amplifier to the input on the Hot Plate using a speaker cable and then connect speaker output 1 or 2 of the Hot Plate to the speaker cabinet using another speaker cable.

I am using this with a Marshall DSL 50 watt head into a 2x12 Marshall 1936 cab.
The unit does not create any additional unwanted "noise".
The Hotplate does exactly what it's supposed to do. I use the 8 and 12 db settings the most and they allow me to get the tone that normally would require me to turn my amp volume up to 6 or higher which is just too loud for normal use.
The Bright and Deep switches work well and I use them both. The more you attenuate the more useful they are.
One note - when you use the 16 db setting, the sound quality suffers a bit but may be a reasonable trade-off if you are in an apartment or for late night playing/recording.

I just got it but it seems to be built solidly.

I called them with several questions before I purchased it and they were always available and answered my questions.

I play Rock, Metal and Blues and this is a great practical addition to my equipment. I would recommend the Hotplate to anyone who has a tube amp. Fact: In order for tube amps to sound their best, especially Marshalls, they need to be cranked with the volume turned up. Again, the Hotplate allows you to that "cranked" tone at reasonable levels.

I bought a brand new THD 8 ohm hot plate to see if it would have any positive effects for using with my Almost new and fully checked out Ashdown Fallen Angel Amplifier running in to my 8 ohm Mesa rectifier 4x12 cab with Celestion vintage 30's

It did not come with any instructions or manual of any kind.

The amp and cab settings where 8 ohms and the units are not switchable so it would be impossible for me to set it to an incorrect ohm setting.

So while it should have been very straight forward and simple to use it turned out not to be.

I had plugged this unit in to my amp and was playing through it, as it turned out the sound was diminished in volume but with no improvement in sound. The master volume built in to the amp is all that is needed to use it with the gain and volumes of the channels cranked as high as one likes and the sound is not noticeably different then when playing it with the master volume up louder. It simply is louder, with the THD hotplate it cut the volume but had no other effect. It was worthless.
That is not the bad part though. I had been watching the VU meter of the amp to see how much power I was running through the unit while I was trying it out, however I did not notice during the 5 minutes I was using this unit that the tubes in my amp were overheating to the point where they were glowing orange and starting to smoke. I shut down the amp immediately and now the amp does not work at all. I will need to have it diagnosed and retubed at what cost I do not know yet.

In retrospect the amps master volume works perfectly and there is no advantage or need for any attenuator. It seemed to be a reasonable thing to try out the THD to see if it would make playing at lower volumes to have any advantage, as it turns out it did not sound better and damage my amp.

The thing was brand new and took 5 minutes to severely damage a new and expensive amplifier. I would never try this again.

I was obviously quite upset that this had happened to my amp. THD is located in the area I live in (Seattle) I sent them an email immediately after this had happened asking them what they would like me to do as far as taking the THD unit and my amp to find out what went wrong. I left all sorts of contact information and sent them my issue through their tech support method. THEY DID NOT EVEN BOTHER TO REPLY TO MY ISSUE! I GOT NO RESPONSE WHATSOEVER! THEY COULD OBVIOUSLY CARE LESS THAT THEIR PRODUCT HAD DAMAGED A VERY EXPENSIVE HALF STACK, I HAVE NEVER HAD A WORSE EXPERIENCE INCLUDING NOT HEARING ANY REPLY FROM THE COMPANY AFTER THIS HAPPENED. IN MY OPINION THIS COMPANY HAS ZERO INTEGRITY AND I WOULD NEVER SUGGEST ANYONE EVER BUY ANY PRODUCT MADE BY THIS COMPANY. THERE IS NOTHING WORSE THAN HAVING A COMPANIES PRODUCT MALFUNCTION AND THEN IGNORE THE SITUATION THAT THEIR PRODUCT HAD PUT THEIR CUSTOMER IN TO. NO REPLY OF ANY SORT. I DONT KNOW HOW MUCH WORSE IT CAN GET THAN HAVING A CUSTOMERS EQUIPMENT DAMAGED BY YOUR PRODUCT AND THEN SIMPLY IGNORING THEM LIKE THD DID TO ME. BOTH THE PRODUCT AND THE COMPANY THAT MADE IT HAVE LEFT ME WITH A DAMAGED EXPENSIVE AMPLIFIER AND COULD OBVIOUSLY CARE LESS. I DONT KNOW YET HOW MUCH IT IS GOING TO COST ME TO REPAIR MY EQUIPMENT BY USING A THD PRODUCT, BUT THEY CERTAINLY DONT CARE. I GOT MY MONEY BACK FROM GUITAR CENTER WHERE I PURCHASE THE THD HOTPLATE BUT I AM LEFT WITH HUNDREDS OF DOLLARS OF DAMAGE CAUSED BY THE THD HOTPLATE AND THEIR LACK OF DESIRE TO INVESTIGATE THIS AT ALL.

Obviously I could not recommend any THD product to anyone, it is one thing to have a product malfunction, it is another for the company to ignore this when it happens. I was upset that my expensive nice amp rig was damaged but was outraged when THD refused to reply to my contacts asking them where they would like me to take the amp and THD product to have them diagnosed to find out what happened.

I have had issues with product I have purchased before and almost all of the companies have promptly addressed the problems and had me take them to service centers to investigate and decide what the issue was, even when I have not had the company consider the issue covered under warranty at least they acted quickly and made the effort.

It is inexcusable to ignore a customer that has purchased a brand new product from their company, had a major malfunction and then totally ignore the customer as THD has.

Every other company I have dealt with have either been outstanding or at the worst acceptable...except for THD.

very easy to use - straight forward,but brief user manual. -16 db setting is a bit anemic, but has a place for quieter practice sessions.

using this with fender amer. strat fitted with texas specials and gibson les paul. No more noise than without unit. Hot rod deluxe amp. nice way to get the overdriven amp sound without the ear spltting volume. A real must for anyone playing at home with a need to light up the tubes without killing the neighbors. I can finally get the sound I want without trying to muffle my amp.

very simple, rugged design. I am not a gigging musician, but can't imagine why you would need a backup in any gigging environment, there doesn't seem to be anything "fragile" about the unit. The only thing that might cause damage would be misuse(amp that is not compatible?)

no experience

I have had opps. to play through different models of thd hotplate and found them all to work for their intended purpose. Unit is a bit price prohibitive, it took me awhile to part with the money for it, but for the sound quality that it enables at lower volumes its worth saving for. I play blues and classic rock and a warm overdriven tube amp sound is essential, no effect pedal can make up for it - only enhance it. I highly reccomend this to anyone trying to get that tube sound without sustaining hearing loss!! Buy this before the distortion and over drive pedals, then decide what will really help your sound beyond real classic tube breakup and distortion.

The hotplate is real easy to use just follow the instructions,and you're ready to go.

I use the hotplate with a 1980 Hiwatt bulldog, these amps are not like other Hiwatt amps. Yes, you can get clean shimmering tones by turning down the guitar volume,but the bulldog is made to distort and get super mean.... and ungodly loud for 50 watts. The Hotplate saves my ears, by backing off 2 clicks on it the Hiwatt is tamed enough for practice, and playing any guitar with p90 pickups,well the combo is unbeatable.When you back off another click or 2 on the HP the sound does become more compressed and thus suffers a bit, but like I said,this amp is made to kill, not sit in a bedroom.

I had a power soak back in the 80's that I used with a Hiwatt stack, I believe it fried the amp. As was the end result of many amps that used these early model attenuators. But with tech advancements the hotplate has been working well for over a year. In fact my friend just bought a 16 om version for his marshall superlead 100, after testing mine out. Over all these things are built to last.

I have never had to deal with THD but I know they have a solid rep.

I have been playing over 30 years, mostly hard rock / punk rock and some heavy blues. I have always played Hiwatts but do own a Vox ac50 cph, and a fender princeton 65. Neither need the HP due to the fact that both have a master volume control. But if the HP were stolen, I would get another one, although they are expensive... I bought mine for $300.00 a year ago, and my friend just recently paid $348.00 for his. I am giving it an overall rating of 8 soley because of the price.

This unit is pretty strait forward, in terms of use. the only thing worth going over is that you MUST use speaker cables, not instument cables.

From my experience with this product (1.5 years) it does what it is suppose to although, if you are planning on using it with you 70's 100 watt Marshall you may be disappointed. I use the HP with a Gibson SG Standard, and a Epiphone Les Paul into a Peavey VK212 100 watt, and an Epiphone VJ Half Stack with great results. With this i'm able to get closer to the sound of many of my idols, such as Angus Young, JImmy Page EVH,Andrew Stockdale, and Robin Trower because there sound is the effect of power tube saturation. The highest i can get on the VK before the sound gets mushy is about 1:00. After that point the sound is as i said mushy and many notes become undefined. But with the VJ i can go all of the way up without a bad sound. I feel that the tone switches do there job, especially the one that adjustes the higher freq. I have used the line out with good results also.

For about 15 gigs and a year and a half of abuse it stands up really well. I use it without backup constantly.

never had to deal with them

I really like this product for all it does. the only bad tones come out when you go to -16db and below (the load setting works well on quiet stages). the only thing i wish it had is an impedance switch (like the bad cat leash, check it out).

Not a whole lot to it. you run it between your amp and the speakers, and basically adjust the DB you want reduced. the reason I rate it a 7 is because some people believe that you will be able to crank an amp and get perfectly good tones at bedroom levels with no coloration of tone, and that is simply not the case. This product will let you drive the heck out of your power amp, but a good part of sound is the air being pushed, and if you are actually reducing the volume, not as much air gets pushed. Control wise, not a whole lot to it basically one knob, unless you use -16 Db, then you have a fine tune knob.

I play Epiphone Les Pauls with EMG 81-89, and an ESP MH series, into a Mesa Single Rectifier Solo Head and Mesa 4x12 straight Cab. Mesas are known for their brutal distortion, but many people go wrong believing that this sound is achieved in the pramp. Mesas need to have the power amp cranked and the gain backed off of to get a nice tight metal sound (metallica ish if you will) So the Hotplate allowed me to crank the power amp to 2:00 when normally i could not get past 9:00 without having everyone at practice complain. There is a small bit of coloration in the tone, but anything you run anywhere will color the signal. Has a bright and deep switch, found them useful if you are going to try it at lower than practice volumes, helps compensate for tonal coloration. At higher volumes I think the bright switch alone sounds very good through my amp.

Haven't had it for too long, but it seems to be built pretty solid, no power issues I can think of, because it does not plug into anything. I would probably be able to go without having a back up because I don't see how that thing could fail.

never dealt with them.

I play a lot of Metallica, BLS, Ozzy, Megadeth, Pantera style music, although I rarely play any of their songs, their style influences me, so naturally your music sounds a little bit like them. I am able to finally acheive the tone (for now) I have been trying to get out of this rectifier for a year now. Its worth the tubes that you will go through. I bought this because I heard it was the common way to go and for once joining the bandwagon worked out pretty good. Definately worth the price I paid.

Couldn't be much simpler really. Amp>hotplate>speaker. Set the attenuation level, decide if you want to switch either of the pre-set EQ functions in, set your amp up to sound good.

I use this primarily with a MIA strat, Maton JB6 (SG type of guitar)and I have played loads of other guitars through it from pointy headed deliverers of death metal to jazzers. I have principaly used it to control a Mesa Boogie Nomad 55 (with EL34's), a 45 year old Jansen Bassman 75 (NZ version of the Fender Bassman 75, complete with 7027A valves)and, most recently, a Epiphone valve Junior head (EL84). It works with everything, if the sound of your gear is good the hotplate won't interfere with it. I think it does a brilliant job of helping control the volume of your rig while letting you get those power valve/s crunching. Without it, my 2 big amps (55 and 75W) can be too much in smaller venues with the 75 delivering some seriously bone crushing volume to get those 7027's breaking up. The hotplate gives you better control. On my little 5W non-master Epi amp it means I can drive the EL84 hard at reasonable volumes at home without drawing serious hate from the neighbours, family and pets.
I think the 2 EQ switches work really well and help tweak the tone as you switch in more attenuation.
What it won't let you do is run big rigs at bedroom volumes. Once you are setting it higher than 8db you are starting to seriously lose the speaker dynamics out of the sound - things still sound good/ok but not magic.
I've never used the line out function so I don't know how good or bad it is.
All in all this device does a really great job.

Very reliable. Don't think there is much to break to be honest.

Never had to deal with them. The info on their site is really helpful though.

Damn fine bit of gear. Just be aware of its limitations and you won't be disappointed. Works for all styles of music. If it were stolen I would track down the offender, beat them to death with the hotplate, wipe off the blood and gore, and start using it again. Or maybe I would just buy another.

The unit its self is pretty straight forward. Just plug your head's speaker output into the input of the hot plate, and plug the speaker output of the hotplate into the speaker cabinet. Getting a good sound may take a little time though. When the power tubes are pushed into saturation or overdrive, they respond very differently than they do clean. This will require some tweaking of the EQ, gain, or presence settings on the amp. All in all, not a very difficult or time consuming task.

Sound quality is great. with a little time, i was able to find a sweet distortion sound. I am running a gibson les paul studio with a duncan JB pickup into a Carvin 100 watt MTS tube head loaded with groove tubes E34L's, with the matching 4 x 12 cabinet. I rarely use effects, but I sometimes use a boss chorus, or occaisonally when more effects are needed, I will use an old alesis quadraverb. Lately I have been running straight into the head. The sounds I can achieve using the hot plate are great. I have the lead channel volume at 10, and I adjust the gain from anywhere at 2 for a good crunch to 7-10 for intense metal distortion. All the time, the output tubes are running at 100%, and that's what makes all the difference in the world. I haven't heard any of the "fuzzy" sounds, or the hissing and popping that some other reviewers are reporting. Even with the unit at -16 db, my tone is coming through nicely. The product really does what it claims to do. It allows you to run your amp full bore and tame the volume. I'm not gonna claim that the tone is prefect, speaker distortion is important too, but it's light years better than running the amp at low volume, or resorting to solid state modeling amps.

Seems pretty sturdy, not too much to go wrong. I would definitely gig without a backup. Worst comes to worst, just us the amps volume.

Never had to deal with them, but I've heard good things.

I play various styles, from classic rock (beatles, stones, floyd, neil young), punk (social distortion...), to metal. I've been playing bass, and guitar for about 15 years, and I've gigged with a lot of bands. I am a total tone junky, and I'm not easy to please. I also play a 72 fender strat, and an ovation acoustic/electric. I also use a silverface fender champ. This product has really impressed me. I've heard other attenuators, like the marshall power break, and this one is by far the best I've heard. It is a little pricey, but definitely worth it. If it were lost or stolen, I'd replace it immediately.

Easy to use- but I still managed to screw up once (doh!). Plugged the thing in backwards (Doh!) and it still kind of worked, didn't damage my amp or the unit.

IF you plug it in correctly, it's easy: one knob to set level of attenuation, an extra knob for the extreme attenuation (you probably won't use much), two switches for bright and deep boost.

No power cable (gets its power from the amp signal)

There is a simple 1-page manual available at THD's website. You hardly need it.

This is not an effect per say, but an attenuator designed to reduce your volume while retaining the glorious tone of your tube amp turned up loud. It does that very well. At anything from -4dB to -12dB it sounds really great. At -16dB and beyond, the tonal quality suffers noticeably, but given the physics of sound and the physiology of our ears it is probably not physically possible to achieve perfect tone with that much volume cut. If you need that much attenuation, you should just buy a smaller amp, or get one with a headphone jack

It does its job very well. I can hardly ever turn my 60W Fender Supersonic amp up full bore, and if I do I'm damaging my hearing and peeling the paint off the walls. This device allows me to turn up into the upper half of the dial on my gain and volume knobs where the tubes really wake up and sing, while still operating at a volume that won't hurt anyone or summon the police to shut down my jam.

I play a '79 Stratocaster (Kinman pups) > a few effects> Fender SuperSonic 60W 1-12" combo amp with the Hotplate between the speaker output and the speaker.

I bought mine several years used and I've had it 4 months. The case seems bullet proof. I dropped it hard on a linoleum floor from a height of about 4 feet and it was undamaged (but it scuffed the floor).

I would use without a backup. if it failed, I could always just turn down my amp, use the attenuation from my amp's effects loop volume knobs, and make it through the gig.

As mentioned above, I did a bonehead thing and operated it for a while when it was plugged in backwards (doh!). It actually sort of works like that, but not so well. I remembered that time I dropped it and thought I'd broken it. I e-mailed tech support on a weekday morning and got a helpful response within an hour. Later I called them at 4:50pm on a Friday. left a message, and had a call back by 9:30am Monday morning. I got on the phone with Ed of tech support, and he was very helpful, very patient, and politely refrained from calling me a dummy for doing such a clueless thing as to plug in my unit backwards (said he gets 3 calls a day for that).

That rates a 10 in my book.

I play surf guitar, rockabilly, and 60s-90s rock. Against all odds I now find myself playing in a church band. I've been playing guitar on and off for 40 years. Electric guitar on and off for 25 years (I'm just back to my Strat and my rock n roll roots this year after a 20-year detour into purely acoustic guitar on Planet Bluegrass).

This device brings more tone out of my amp, and makes everything else I do sound better. It has no bad interactions with any device I own (Crybaby wah, Ibanez TS-9, Ibanez FL-7, Digitech delay). I find that with this device, and my hot pickups, and my modern tube amp, I have less need for an overdrive pedal.

It won't fit in a rack, nor on a pedalboard, so it perches on top of my amp. It kind of needs to stay near the amp, but I'm trying to think of a way to mount this thing somewhere so it won't fall on any more hard floors. Maybe I can build some kind of bracket or cradle for it.

It is a glorious and very fetching purple color. It has a light bulb on the front that glows brightly when I hit loud power chords. It gets warm, but not really hot with my equpiment. It's rated for bigger amps and might get pretty hot handling a Marshall stack turned up to 11.

If it were lost, I would not hesitate to buy another one. Or maybe I would try some other THD product. I'm curious about the Yellowjackets, and their amps (spendy though they are).

I sometimes wonder if I'd be better off using a smaller tube amp (say a 15W Fender of some sort), instead of a 60W that needs attenuation to use in most cases. Maybe I just need to hook up with a louder drummer.

Get your tone in order. Then hook this beaut up and don't go below -12dB. Job done.

I use a Burns Bison or Fender Jag (Quarter pounders installed). These go into a modded Crybaby, Boss OC-2, Boss OD-3, ProCo Dirty Rat, Russian Big Muff Pi (Modded and no sounds like actual sex). This leads into a Marshall Bluesbreaker. Before the Hotplate I was running the amp volume at 2, and compensated with a Wasabi OD to drive it. It sounded pretty good, but after loading the amp with Philips 6L6s, Sovtek GZ34, JJ ECC83, and some EHX 12AX7's I spat my dummy out.

NOW I run the main channel at 10 and the secondary channel (via crosspatch) at 6/7, with the Hotplate at -8dB.

Game Over. It is as close to dammit the tone I have been searching for. I can gig safe in the knowledge that the sound engineer will not throw a massive hissy fit, and still retaim the SexTone.

Deep and Bright Switches - I use them, as I'm in a duo with guitar and drums,a nd it helps fill out the sound very well. Some may not like them but hey, that's life.

Some ProDads may reckon it colours your tone a tad. I say bollocks to that.

IT HAS NO BATTERY. IT DOES NOT RUN OFF MAINS.
Jebus, it is powered by the amp signal; when you don't play it isn't on.

I baby it a tad, but only because it is that important. I echo an earlier review that if it were not for the Hotplate I would have sold my amp.

Dependable.

DONT USE THIS FOR 'BEDROOM' PLAYING. IT IS A STUDIO AND LIVE TOOL. I CANNOT REITERATE THIS FACT ENOUGH.

Not used.

Playing for ten years now. Fits beautifully for my egotistical Glam/Punk duo approach. No bass. No other guitar. Just me. And with the THD it still sounds like there's more than one. Great product.

If it were stolen I would hunt the culprit down and break their legs. Then I'd liberally chuck playing darts at them whilst they writhed about.

For the price I paid and the mint condition. A bargain.

I don't think it came with a manual...wasn't paying attention when I unpacked it. But it's simple enough. Make sure the impedence is right, plug it in right, and play with the switches until it sounds good....it's that simple.

The sound is both awesome and disconcerting.

I run a 5w Class A Tube amp wide open (using guitar volume to control breakup) into a Vox Cab with no other effects. Without the attenuator, this is my favorite guitar sound by far (better with marshall, black kat, /13, etc.). With either humbuckers (SG) or single coils (G&L Legacy) the breakup of the amp is amazing, but...as we all (should) know, wattage implies nothing about sound levels...and it's really loud.

The attenuator takes the edge off with the first few settings so it won't kill your ears, and it doesn't really color the sound while it's doing it.

On the adjustable setting, which I use a lot...the sound is just not the same...simply because it's not a full-on amp running behind you. Someone below described it as going from a full-on amp sound to a good recording of a full-on amp sound and I couldn't agree more. It's not the best thing in the world, and I avoid using it any time i can...but to be able to get something resembling that tone at an apartment-frienly volume, it's certainly worth it.

One other use I'm toying with is using it to give my amp a line-out and basically using it like a distortion box going into other effects and a shimering clean amp...but as I only have one amp right now, I haven't gotten the chance.

So, it works as intended and the sound is acceptable for my uses...but don't expect it to make you able to play a full stack in your bedroom. That just won't happen.

It's entirely passive and in a big metal box...can't imagine it breaking.

As long as you're not expecting miracles, it works well...and certainly better than a $200 practice amp.

Very easy to use. The only difficulty I had was that my combo amplifier had a very short speaker cable so I had to find an extension cable.

I am using this on a 20 watt combo amp similar to a Fender Deluxe. I have the attenuation set at -16dbm, the bright switch on and the bulbs on. Initially I ran the amplifier volume at full to get the maximum tube overdrive. This gave a nice smooth distortion and sounded very similar to the amp cranked just much less volume. For me where this unit really shined was when I ran my amplifier at about half volume. At this level and -16dbm it was a very jam friendly volume. The difference now was that the sound was clean but on the edge of breakup with plenty of glorious sustain and harmonic richness that you would expect from a tube amp. I can't put my guitar dowm!

Don't know yet but the unit seems very rugged.

I think this is a great accessory for getting hot tube tone at lower volume without sacrificing sound quality. For those looking for mega-distortion get a pedal, for those who love the tone of their tube amps but need lower volume for jamming or recording this is it!

EASY

This is the Truth and told to me by a tech at THD it was designed for many different purposes and one of them being playing your high powered amp at low levels while maintaining a fully driven load from the pre and driven tubes. the attenuator absorbs the power and converts it changing its in essence signal level and correcting equalization to match the power setting at the high volume....... to all those who say this item doesn't work well i have no clue what you might be doing wrong.. i have a three charvel custom shop under fender i run them through a custom Mesa Triple i bridge it between my 8 ohm. speaker out to speaker 1 out to the 8 ohm cab in. at -16 it sounds amazing i can run it through my fx loop because it is getting all the power and then after out of the amp it is converted to the speakers.... if you have a bad or poor sounding cab THD put some switches on there for you deep and then a high end boost is what it sounds like to me or a balanced and bland unity but it seems alittle more tailored eq wise to clearing a very dry high end boost. regardless i do not personally like to use them there is no point. i am running this ingenious Plate through a custom mesa oversized, baffle and back insulated to my specific sound... when i am at home i like to play and to make a long story short i can get an amp that will sound the same as mine so i stumbled across this and i love it. there are many other amazing features... this is a must have for anyone who loves your tone. i have tried substitutes and someone even mentioned its not for low volume use..... what ? also he suggested buying another amp like a practice amp i believe and played for 40 years.... uhm nice thorough review but not practical if you have an amp that sounds like no other and you have found your tone this is an amazing tool. its good for much more with a load option but -16 sounds better than it would with it at low volumes and with out being able to drive the tubes successfully. the speakers most will notice since they are not at there peaking point or the desired point will not sound as great as at full volume but you will notice it will sound fairly similar but when you open this up it will separate more.... meaning more definition and tonality but much better than opting for a POD or other digital modeling unit cause i tried it all and this is honestly the best so far...

yeah i suppose so toured with it to give it a test and it was awesome for warming up back stage.

have not dealt with them but i need to ask them a question so i will see i am sure they will be great most are. especially boutique manufactures.

i trained musician. professional back to have been active musician for a while.. i record and produce bands. i play whatever i decide i would like to, not genre specific.

Plug it in and turn turn the knobs. It takes a little time to figure out the Deep and Bright buttons and how they interact with the different levels, though.

Unlike most owners below, I don't use it to tame a monster Plexi, Recto, or 5150 head. I use a Traynor YCV40WR, mostly clean, with a Tele and a 335-style. What the Hot Plate does is let me turn the amp up to the 3-5 range, where the power tubes open up and the sound gets really fat and dynamic, without hurting anybody. Normally these levels would provide a volume that you can barely shout over from across the room; with the attenuator, the levels are perfect for a basement jam environment, and even work for un-miced vocals. And to my ears, at least, the sound quality is very good down to -12db. (16 gets a little murky, but still sounds pleasing.)

I've dropped it on concrete, and it's still ticking. Solid.

Quick email response; I bought it used and they still seemed interested in helping me out with questions.

If you want raging power-tube distortion without waking the baby, get a Pod. But if your goal is to bring a 40 or 100-watt amp down to about the volume level of a Champ so you can open up the throttle, this will do it. It's awesome at what it does.

After reading other reviews, I'm not sure what other purchasers were expecting. It functions as promised and does exactly what it's supposed to do. It's laid out nicely and has straight forward controls. The manual provides adequate instruction for use and is to the point.

I currently use a Peavey 120 Ultra head and a 4x12 cab with Celestion speakers. Gibson Les Paul 58 re-issue and a PRS Custom 24. So far the Hot Plate is operating as promised. You really need to be at the -16db setting to play quietly enough not to wake the family, but I've found the sound to be very acceptable with minimal tonal coloring. It's a nice addition to my current rig.

I haven't had it for that long, but it's construction is first rate. So far it's very dependable.

I had a question about the impedence for my cab(s) and the tech that answered the phone was more than helpful. He went through everything very thoroughly along with pro's and con's to my anticipated set up. I would caution anyone to call first before buying to make sure you get the right unit prior to purchasing. If you have two 8 ohm cabs, you need a 4 ohm hot plate. Two 16 ohm cabs, 8 ohm hot plate etc...

I play rock and blues. I've been at it long enough to know my limitations and long enough to continually push them. I have more gear than I care to list here. If it were stolen, I'd buy another one. It works like it's supposed to. I like that it's straight forward and easy to operate. The bright and deep switches are a nice touch when playing at the -16db setting. I hate the price. $300 is a little pricey for most. I looked at he Marshall Powerbrake and the Ultimate powerbrake. This was the best value for the money. I can't stress enough how great the customer service is. Call them with your amp first and they'll make the proper recomendation. Then go buy it on ebay....ha.

This unit does EXACTLY what it is supposed to do, and MUCH more. I am really getting tired of hearing these other guys complaining that it doesn't lower the volume low enough for their bedroom when they use it in an apartment...............so ignorant if you really think about it.

If you own a Marshall master volume model for example.........why even use the hot plate in your bedroom at all? Simply turn the pre gain volume up and the master volume down..........what more do you want?? This unit was made for using in a live Club or even larger venue situation, and to run time based effects cleanly via a second amp (or a couple of other ways)and control your over all saturated volumes to a usable volume.

Now, If you own a non-master volume amp, you will need to use the 16 db setting and volume control pot and just deal with the sound, which is pretty good if you use the two EQ adjustments on the Hot Plate itself and maybe some pre or post EQing via an "MXR 8 or 10 Band EQ" or something similar.

There is another use for this unit that FAR outweighs the volume attenuation that these guys are not even paying attention to.............and that is the ability to solve an age old problem with "time based effects" being in the chain BEFORE the preamp section (via the guitar input jack) or before the power tube section (via the effects loops) causing terrible distorted and muddy effects sounds that completely destroy the original beautiful saturated power tube sound that we all love so much. This has been a HUGE problem overlooked by the majority of guitarists who obviously don't do their homework when it comes to great sound and the inherent problems that are caused by pre-distortion (Pre amp OR Power tube)followed by time based effects.


With the THD Hot Plate and TWO similar amps, you can solve this problem VERY nicely, and you can now get that incredible 70's Hard Rock distortion sound AND great time based effects as well without killing the original signal. You do this by running your guitar through the input of your best sounding ALL TUBE AMP (Amp #1) and running the preamp sections at a low setting (preventing that fizzy preamp distortion), and running the power tubes between 7 and 10, getting that beautiful FULL power tube saturation that we all love. Then you run the head #1 through the Hot Plate and then to your one or two 4 x 12 cabs for an undisturbed, unaltered saturated sound. THEN...........you run a speaker cord from the THD Hot Plate's adjustable LINE OUT JACK located on the back of the unit to your EFFECTS PROCESSOR (mine is a Digitech RP20) OR to your effects pedal chain, and THEN run that into the INPUT of AMP #2.

You want to run Amp #2 as CLEAN as possible in order to "reproduce" all your heavily used time based effects (Chorus, Flanger, Delay, Reverb, etc.) cleanly and fully for the rich sound that they can produce, and mix the "clean" and the "wet" amps signals to your desired effects level for your overall sound.

This is the ONLY way (besides going even further and using dummy loads, and isolation cabs) to get that great time based effects' sounds WITHOUT having to run the effects through the MIXING BOARD's Effects loop allowing the sound man to control your effects and being able to mess them up!! I don't know about you, but I want complete control of my sound from A to Z.

I gave this a "9" for sound quality because there is always room to improve this type of unit. I am currently using TWO Peavey 5150's (a 5150 signature and a 5150II signature model) and a Digitech RP 20 effects processor along with a separate floor pedal set up: A "Script MXR Phase 90, an original MXR Script Flanger, MXR 10 Band GEQ, and a EH Holier Grail, EH Memory Man, EH Del Electric Mistress, and a new Echo Plex made by Fulltone (incredible unit),and have been pulling my hair out trying to get the sound I wanted out of them like I heard when I heard Van Halen live. And I have been searching for a way to have POST preamp/effects loop/power tube/speaker/mic time based effects too, which is the BIGGEST problem I wanted to solve.

I can now get all the sounds of my favorite artists like I have wanted for years. I can even put my EQ based effects (like Wah Wah, Compressor, Distortion box, phaser , etc) in the PREAMP section (Guitar input) via separating the time based effects from the EQ based effects using the Left and Right channels of my RP 20 to rout the effects in two different directions........VERY nice to have that ability.

So, for all those here who say that this unit doesn't do what it is supposed to do........TAKE A CLOSER LOOK AND READ ALL THE INSTRUCTIONS!

This thing is built like a tank, what more can I say? I have only had it for 3 months, but it looks like it will last a lifetime.

I have been in communication with these guys several times while I was trying to figure out how to solve the problems I talked about earlier, and they were GREAT about taking the time to help me, unlike most places that don't care about helping their customers post purchase since they already have your money.

I have been playing guitar for over 40 years and I play mostly 80's style Hard Rock. This is perfect for that genre, as well as any other genre I can think of. You already know what gear I use, except for the fact that I actually have FOUR 5150's and eight 4 x 12 cabs that I usually run in stereo in larger venues. I even use four 4 x 12 cabs in small rooms for the stereo effect, and the fullness and punch that they pack.......PLUS I have to have the 8 ohm impedance for my THD Hot Plates.

If this unit were to be stolen, I would immediately replace it (them) with brand new ones just like this one. It is the very best unit that I have ever used and I have used just about ALL of them. This is MORE than just a volume attenuator, it is a miracle device for me and anyone else who wants great time based effect sounds.

I love the way this thing sounds even when you cut the volume db by more than 8 db. It maintains pretty much ALL of it's tonal characteristics at least to that point.......AND you have the two built in EQ settings that work good enough at these db level drops. The noise reduction system in this unit is great too. It is in NO WAY to be used as a substitute for a full on noise gate, but it certainly is great for that FINAL overall tweek. I use ISP Decimators (4 of them).......... one in each of my effects loops of my 5150 heads, the best noise gates I have EVER heard........simply amazing and easy to operate.

I have compared this Hot Plate to literally every attenuator out there , both new AND used and NOS.........there's no comparison, the Hot Plate is by far the best. There is, However, still room for improvement......such as maybe a way to go from the Hot Plate to FOUR amp cabs? Older Marshalls had the ability to use 4 cabs, instead of 2, and I loved that. And if they can ever make a board that completely keeps the original tone no matter how much you attenuate the volume, that would be nice, but definitely NOT neccessary.

I don't hate anything about this unit, and I love everything about it.....enough said. This unit helped me to make music because I just can't get enough of the fantastic sound I can now get from power tube saturation AND extremely clean time based effects, all in stereo!!!

I would like to share one more thing to all the younger musicians out there. Just because at first glance something doesn't sound great, or you don't take the time to experiment and get great sounds, doesn't mean that the unit is bad, or overpriced. It is up to YOU to experiment and to try different things.........after all........the glory is in the adventure, it's "in the ride", NOT the end.

The hotplate is very simple to use I like the fact that when I have my amp on the bench to bias tubes or check voltages it has a built in Dummy load.

I have a 100 watt handwired Plexi that I built, that I use through the Hotplate, I have mixed emotions about this attenuator, at 12db of attenuation my amp tone is acceptable and is very dynamic and is very touch sensitive. At 16db of attenuation the hotplate has a varible volume control, cool feature but your dynamics and sensitivity dissappear, your basic tone is present with the addition of a fizzy sound at the end of your notes. The fizz does become less evident with less attenuation(louder volume) this is where I will complain, THD could have cleaned up the 16db setting and gotten rid of the fizz. I would love to play my Plexi in my condo but Face it, Attenuators were made to tame 100 watt non master volume amps to play at stage levels not to play in your bedroom........

I would say that the unit is built very well

N/A

Attenuators are a necessary evil for Plexi's I have a love hate relationship with my Hotplate, I will keep it for the Dummy load function alone for when I need to Bias or am building amps. Keeping in mind that it is impractical to play a 100 watt non master volume amp in a condo or at bedroom levels you are missing the magic when you do this. you might as well play your master volume amp at low volume.... Plexi's are amazing cranked up but your ears cannot take the sheer volume of this amplifier, you value your hearing you will use an attenuator. IMO the Hotplate is a good solution but is far from being the ultimate solution. I will be looking for a better sounding attenuator in the future,

Easy . . . pick the ohmage you want. Buy it. Plug it in. Manual explains stuff, but there's not too much to say. Pick your attenuation, and decide on the deep and bright switches (and the noise-reduction bulbs). Use proper speaker cables though!

JCM 800 2203 w/ various guitars into 8 ohm 4x12 cab. Does pretty much what it's supposed to do. I don't know how much of a noise difference the bulbs make, but they look neat anyways.

I was really irked by some of the earlier reviews claiming poor sound quality. I just have to make it clear that this is not the fault of the attenuator. As someone said before, speakers don't move the same at low volumes, especially in high-wattage cabs found on the sort of amps that need a hot plate!

This is NOT a tool for cranked 100w Marshall in your living room. The Hot Plate is for taking an amp that's so loud you can't play small-medium clubs, and taking it down to those levels . . . which are still quite loud!

I usually use 8db attenuation with the master around 7. Sometimes I'll go to 12. I'd say that you can hear a bit of the frequency-shifts that come from attenuating from 12--->on. The deep and bright switches are neat, but I never use them; they're really not need that much on -8db.

Anyway, the thing sounds great for taming an amp that would scare off audience members and bar owners. That's what it's for!

It's never given me a problem . . . but here's the thing about gigging without a backup: My amp has.

Nothing major, just seems to blow fuses more often than it should . . . but I don't know if the Hot Plate is connected.

Other people say they've had no trouble. I don't get the master above 7 anyway, and I'm not using really heavy attenuation. My speaker cable is all up to spec too. I have no reference point for blown fuses, as I never got the master about 4 for any period of time before I got the Hot Plate. When I opened the amp, the blown fuses were actually slow-blows someone had put where fast-blow fuses should be (I purchases the amp used a few years ago).

Anyway, the point is I don't know. Either way, nothing in the amp has ever been damaged, I just seem to fry 3 of my fuses about once every couple months.

The thing sounds great. It'll give you a nice volume cut to let you use your big amp in venues smaller than a stadium.

I'm giving it a 7 because if my bi-monthly fuse chewing is the fault of hte attenuator, I'd give it a 5, and if it's not, I'd give it a 9.

My setup - Fender custom shop strat, Brownface & Blackface Fender amps.

Of course it will affect the tone of the amp in some way... What I don't get is people who are upset about the fact that it changes the tone, as if this is some kind of failure to be the "perfect" attenuator. Just turn down the volume on your radio and the tone changes along with the volume. Any reduction in level especially by a reactive load process and especially when applied heavily will change the tone. It is a scientific fact that the human ear is very sensitive to these changes and no design will ever change that.

I actually think the sound is improved by the hotplate because in my opinion, any "great" tone at a level that can damage the hearing or feels uncomfortably loud is a bad tone. For those who think there is no substitute to an unattenuated amp cranked to 11, grow up and stop p****ing people off..... you're too damned loud!

In recording applications, even in a soundproofed studio a maxed out amp with no attenuation can overcook the microphone, which can have negative impacts on the recorded sound (mic diaphragm distortion etc...), so I think the hotplate is an essential tool, not just a handy thing to have.

On anything but a huge stage it is mandatory to use this device if you don't want the soundman and the rest of the band to resent you and still be able to crank your amp. I recorded an entire album with my hotplate running at 12db attenuation and I have had nothing but great praise for the guitar tone and people asking me how I was able to acheive such recorded tones. A good speaker does help and I use tonetubby hempcones which are in a league of their own.

As a tool, the hotplate is the best attenuator I have used. Others I have used had damaged the amp I was using, but the hotplate has never caused any damage in the years I have used them. Of course you will wear out your power tubes quicker.

Never given up on me and never damaged my amp, but remember when using this, you are running your amp harder more consistantly, so the various parts on the amp can wear out more quickly, mainly tubes.

Never had to deal with them

I play original music. Some may call it softrock, some may call it melodic rock, some may say AOR. I don't really know what it is. It's just what I do. See for yourself if you like...

http:www.thelostangels.net

I've only had it a week.

I e-mailed, They e-mailed back.

I'm only writing this review to let people know that this thing doesn't really do what it says it does. If you live in an apartment or row home or if you want to play in your room and not bother anyone this thing will not bring the volume of your amp down. It has 5 settings not counting the load setting. -16dbs, -12dbs -8dbs -4dbs and 0 which is basically a bypass.

The only setting that you can control the volume to were you don't kill small animals is the -16dbs and you can read other reviews on here at -16dbs it doesn't sound all that good. Once you switch to any of the other settings -12dbs or lower the right knob which they call the potentiometer is inactive. The only time this is active is when you set the Hot Plate to -16dbs, any other setting and this knob does nothing. which means the only way you can control the volume is by turning down the amp which in my opinion defeats the purpose of the Hot Plate. I have the JCM 2000 DSL 100watt head which is a master volume amp, the Hot Plate manual says to set the volume on master volume amps at full output. Unless you enjoy people hunting you down and blood coming from your ears "DON'T DO THIS" The Hot Plate only subtlety effects the volume at -12dbs or lower so your amp will be as loud as it normally would be without the Hot Plate.

I bought my Hot Plate off EBay and when I hooked it up and could only get it to do what it's supposed to do on one setting I thought it was broke. I didn't want to accuse the seller of selling me a broken Hot Plate until I was sure I knew what I was talking about. So I e-mail THD and told them what it was doing. ED DeGenaro e-mailed me back and told me that it was working fine.

So if your like me and thought that you would have all this cranked amp power without the volume and you could do your best Angus Young in the living room while the wife and the baby took a nap upstairs forget it. Like I said you can bring the volume down on that one setting but it doesn't sound all that good. This review isn't a negative against how the Hot Plate will make your amp sound, I'm just trying to let people that don't know like I didn't that you don't have very much control over the volume. I read lots of reviews before I bought mine and no one mentioned that. I'm going to take it to practice with me where I can really test it out to see what kind of sounds I can get with it before I decide to resell it. It may turn out to be what the doctor ordered but it's not all what it's made out to be.

I used the hotplate with a JCM900 2100 and some marshall 4 x 12. Using a Ibanez SZ320 with stock pickups.

I had the volume on 6 with the pre-amp gain on 6 and the mids etc around 2 o clock.

Using this hotplate really helped catch the power and balls of the JCM900. I play in a metal band so my sound has to have clarity and power amoung the amount of distortion i use. It shook the whole room and it sounded better than i thought it would.

Using the hotplate on -16 setting sounds ok, if i was to play the amp a low volume without the hotplate it would sound bad, but the hotplate makes it sound alot better. But not as good as if it was played loud, mainly due to the speakers not being driven hard enough.

The same as all the other Hotplates, just 8 ohms.

Only had it a week and is doing fine right now

n/a

Overall i would recommend this to any guitarist who uses a valve amp. It really brings your amp to life without damaging your ears. I couldn't ask for anything else on the hotplate as it has everything i need to get my tone. Could do with being a bit cheaper, but you can't sacrifice tone for a cheaper power attenuator if you want to sound great at lower volumes.

Playing a Gibson Les Paul Std and PRS Custom 24 through a Mesa Rect-o-verb head with a 2 x 12 Recto closed back cabinet. With the amp cranked at about 50% the Hot Plate absolutely shines. I play it at mostly -12db and get some really great sounds from the amp & cabinet. At -16db you're gonna loose some tone but the amp still sounds decent. (Also remember, the speaker isn't vibrating like it should at -16db) Your expectations HAVE TO BE REALISTIC. Sounds great with the clean or overdrive channels. I could not use this setup at home without the Hot Plate. Just way too much power for the house. I was gonna trade in my amp for something smaller. NOT NOW, NO WAY, EVERYTHING STAYS, all because of this small purple box.

Purchased Nov.2004
5 ranges of attenuation with one variable at -16db
Has low and high boost switches and noise reduction
Used at home (keeps the wife and neighbors happy)

Going on 7 months no problems, don't foresee any. The unit is built ultra heavy duty, solid as a rock. Looks like it's made for the "long haul".

I did have a situation where I thought the small light, that shows the noise reduction is active, wasn't working. This turned out to be due to my own stupidity.(The light was working the whole time) Anyway, I e-mailed THD and got a response back, the same day, from Andy Marshall, the main-man, the presisent & CEO. He responed back to me twice, really fast. These guys really care about their products and their customers. NO BULL. I can't say enough about how great they are. They helped me really fast, and who am I, just some unknown guy who set up a small room in his house, so he could play his guitars.
They treated me like I was starring on MTV.

Playing for 35 years on and off. (you know the story, job, wife, kids) I've bought and sold more stuff than I care to remember. But, the stuff I have now goes to the grave with me. Not alot, but real quality, all made in the USA. If anything ever happened to the Hot Plate I would replace it in a heart beat. Like I said, I can't use my amp at home without it. The only thing that I wish this unit had was the abiltiy to switch to different ohm ratings. If I ever change speakers and they're not 8 ohm, I have to buy another Hot Plate made to match the new speakers. That could get expensive. However, I don't see that happening. But, that's why it got a 9.

No serious problems here. Pretty common sense stuff, mostly. instructions are rather vague though.

I'd say this is a matter of tast. I play a prs cust24 through an un-moded Soldano slo-100. I use the hot plate with only the "deep" switch on. This gives the amp a much needed boost on the bottom end which I much enjoy. Saved me a rather large sum of money on sending it back to CA to get it moded. I could see, however, how the coloration of the tone might upset some. Try it before you buy it.

Only had it for a short while. No problems yet.

Great piece of equipment. Glad to have it around. I live in a dorm room and would risk a fine if I turned my amp up even above 2 let alone up to 11. I don't mind what it does to the sound of the amp at all. Again, try it before you buy it.

pretty easy to use, when you know how, the instructions are minimal, they allow you to use the unit without blowing up yer amp, that's about it, if you need info on how to use the line out, for useing it as a dummy load, wet-dry set up, forget the instructions, minimal!!

i use this with a les paul into a plexi marshall or a 78 master volume jmp 50 watt head,( play 70's, 80'srock)i strictly play in my home's basement jamming along to records and ocationally with my band.these amps without some kind of attenuation and/or overdrive box to me are useless, as i play at pretty low volumes. for the master vol. head its cool but you can get a similar vibe going with an overdrive box (ts9 or similar)at a cheaper price, there is something cool about the way the hotplate with the cranked head sounds though, but you will have to spend a lot of money on the hot plate and power tubes!(they won't last very long with the amp at full throttle)all and all, you can get a very similar sound by just useing a ts-9 or similar, i'm really not sure if it's worth the money for this type of setup. However, for the plexi, it's absolutely the only way to fly!! a plexi cranked in yer basement will hurt you, never mind if it sounds good or not, at those volumes, you will not be able to tell!! just waaaay too loud, with the hot plate, it will scream, nice low end plenty overdrive, sustain for ever, real nice, will put smile on yo face right away, you do loose a little bit of tone at higher attenuation levels but minimal, it sounds really good. i am not sure, knowing how the hot plate sounds now, if i would buy one for the master vol. marshall, but i would not hesitate to but it for the plexi head, if i couldn't attenuate the plexi, i would sell the amp, the hot plate is that good.

so far so good, seems solid, time will tell.

i e-mailed the company asking them to provide more info on how to use the unit as a dummy load, or for a wet-dry setup hoping also for cableing diagrams (different cables must be used as far as instrument vs. speaker cable)didn't get cableing diagrams but they answered me back the next day, pretty quickly!nice to know someone is there.

for a master vol. head it's nice, my only beef here is the price,you can get a similar sound with an overdrive box, it will be just as nice and a lot cheaper and your output tubes will last longer, how ever for a non master amp such as plexis, its the only way to go, a must have piece of gear. no overdrive box in front of a plexi will give you this sound.

VERY EASY TO USE. MUCH DISTINCTION BETWEEN EACH SETTING. I MOSTLY USE THE -16db SETTING. THE MANUAL IT COMES WITH THOUGH IS VERY BASIC. GOT MORE APPROPRIATE INFO FROM THE WEB SITE. WEB SITE IS GREAT. YOU CAN DEMO DIFFERENT LEVELS OF ATTENUATION ON LINE, IMPRESSIVE FEATURE. WISH THE MANUAL WAS AS GOOD.

MY MAIN GUITAR IS A CUSTOM SHOP CLASSIC STRATOCASTER WITH TEXAS SPECIAL SINGLE COILS.I USE A CRY BABY WAH,AND BOSS SD-1 I'VE OWNED SEVERAL TUBE AMPS TRYING TO FIND THAT PERFECT SOUND AT LOW VOLUMES. SOME WERE TOO LOUD FOR HOME OTHERS NOT LOUD ENOUGH WITH A BAND. I HATE TRANSISTOR AMPS SO WHAT ARE MY OPTIONS? SPENT ALOT OF MONEY TRYING TO FIGURE THIS OUT. I'VE BEEN USING A SUBWAY BLUES FOR THE PAST YEAR FOR ITS LOW LEVELS BUT WOULD GET DROWNED BY THE DRUMMER. SOLUTION THD HOT PLATE. I'VE DISCOVERED A WHOLE NEW SIDE OF SUBWAY BLUES AND NOW I CAN GET ANY MODEL OR WATTAGE AMP. I LIKE THIS HOT PLATE SO MUCH I HAVE NOW PURCHASED A 67 BASSMAN WITH 2X12 CAB AND CAN'T WAIT TO CRANK IT UP. IT IS BY THE WAY THE HOLY GRAIL OF ALL AMPS.

SEEMS REALLY GOOD, ONLY BEEN USING IT FOR ONE MONTH. I OPENED IT UP AND EVERYTHING SEEMS VERY STURDY.

NEVER HAD TO DEAL WITH THEM.

BEEN PLAYING FOR 8 YEARS. LOVE BUDDY GUY, CLAPTON, SRV, COLIN JAMES JONAS, AND CLASSIC ROCK. THD OFFERS GREAT SOUND VERSATILITY WITHOUT COMPROMISING NATURAL SOUND OF EQUIPMENT AND PLAYER. IF STOLEN I WOULD GET ANOTHER.
ONE LAST NOTE: "I READ ALOT OF REVIEWS, GREAT WEBSITE HC, ONE THING THAT STRIKES ME IS THAT PEOPLE WITH SHIT EQUIPMENT ARE ALWAYS COMPLAINING AND NEGATIVE ABOUT EVERYTHING. DON'T EXPECT AMPS, ATTENUATORS, EFFECTS, WAHS AND OTHER ADDITIONS TO MAKE YOUR CARDBOARD OR MADE IN TAIWAN GUITARS SOUND GREAT. GREAT PLAYERS AND EQUIPMENT MAKE FOR GREAT SOUND.

As far as I can tell it all depends on what amp you are using. I originaly bought it to use with my Peavey Classic 30. If you disconnect and tape off the main speaker wires you can run an 8 ohm speaker thru the extension speaker jack. The amps OD channel sounded fabulous with the Post on 11 (that's what it goes up to!) and with the Pre at about 5. But talk about loud. Whoa!! Bought and hooked up the Hot Plate and it was all there except for the bass. The Classic 30 uses EL84 power tubes which tend to compress the bass somewhat. But with the Hotplate hooked up the bass got very, very compressed. Very flubby sounding. I don't know if this will happen with all EL84 equipt amp's but mine did'nt take to kindly to it. Soooo, I tried it with my Hughes & Kettner Tube 50 combo, an amp which has basically been collecting dust. This amp was made to be played loud and man, does it ever! The Hotplate has helped to revive my interest in this amp. Finally, I can now turn the Master all the way up and set the OD channel volume on about a 2:00 position and turn the gain up to about an 11:00 position. All guts and glory with no more ringing ears. It's all there for me with no loss of tone. The Bass and Treble switches on the Hotplate are a nice addition should you need them but so far I have'nt had to use them. I can also use OD and Distortion boxes thru the clean channel with the Hotplate and still get some great tones happening at very managable volume levels.

As I said the quality of sound may depend entirely on what amp you are using it with. If you buy one and are not sure how it will work with your amp I would definatley get in writing that you can bring it back. At close to $300.00 a unit you better be sure!!

I've only had it for about 3 weeks now and so far it seems reliable. Seems to be a very well built unit, good and sturdy. Cool purple color too.

I called them with a few questions before buying it and the fellow I talked to (can't remember his name) seemed pretty cool. Took the time to answer my questions. But the big question is how will they be if I need service? I'll give this a 5 based on "we'll see."

Again, your rating depends entirely on what amp you are using this with. With my Classic 30, no go. With my Hughes & Kettner, it's a go.

You can't get a good sound out of it, at best you can get an OK sound out of it, IMO. Hook up is simple, you insert the unit between your amp head and speakers - unless you have a combo amp. Then your speaker cable might not reach the HotPlate on top of your amp, as was the case with my HotCat 30R. You need to make an extension male to female speaker cable. Maybe THD should include this with the HotPlate, it might cost them $2 at most.

Well, this does help make the best of a bad situation, the situation being an amp that only sounds good loud in a place you can't play loud. But does the HotPlate get cranked amp sound at a low volume? In a word, NO. Not even close, but better than nothing. The bass and treble boost switches help a little, but the frequencies boosted aren't exactly the ones needed. Bottom line, don't expect too much and you won't be disappointed. I'm using it with a HotCat 30R combo.

It's built like a tank, for the most part. Big heat sink, with a fan powered by jam! I would give it a 10 here, except for one thing. The first time I used it, the attenuator knob came off in my hand. No big deal, screw it back on, right? Nope. The flat part of the control shaft doesn't match the flat part of the knob, so it will never stay on - I kid you not. I emailed the manufacturer and asked him if my unit were somehow defective. He said no, they're all that way, they couldn't find a knob and control that matched properly, so the knob is just going to come off once in a while, what the hell. Hey, I play a lot of shows and I need reliable gear. If the knob was to come off and be lost, I don't want to be looking for a pair of pliers to adjust my expensive HotPlate while I'm doing a show. I can't believe THD can't get a knob made with the flat in the right spot. I may grind a flat in the shaft with a Dremel tool when I get time.

They answered my email promptly and politely, even if the answer wasn't what I was hoping for. In my opinion, however, the HotPlate needs service right out of the box. It needs an upgrade to a knob that fits and won't come off when you turn it.

In addition to power attenuation, the HotPlate has bass and treble boost switches in an attempt to restore the presence and thump your amp had when it was cranked. It helps - a little. There is also a noise reduction circuit to kill grunge between notes, an optical noise gate. This might matter a lot if you have a super high gain amp that makes lots of noise. I have a HotCat 30R and it basically does nothing with a medium gain amp, so I don't have an opinion. The line out feature (with volume control) is nice, but as you'd guess it doesn't sound like a miked amp. It IS a handy feature if you work on tube amps and need a dummy load while working. I bought it after reading a "shoot out" on HC forums between the HP, a Weber mass, and a Marshall Power Brake. If this is the best, I guess the others must sound pretty bad. I've been playing for 30 years, but only recently switched back to class A tube amps. Pushing a 30W amp until it sounds good is OK in a medium sized club, but not in a small club. I had hoped this would help.

I don't think it could be easier. Plug it in between the amp and speakers and away you go. Two nobs three switches: Db level and volumn pots,deep and bright switches,and a bulb on/off switch, which is a built-in noise reduction system.

I use my 8 ohm Hot Plate with a Fender HotRod Deville. I play either a '57 reissue or Roadhouse Srat,or a '98 Am. Tele. My pedalboard is: Teese Wah, Analogman Juicer (I love this compressor), Analogman silver mod TS-9,Boss DM-3 analog delay, and Boss TU-2 tuner. I am a Blues player, from Mance Lipscomb and Lightnin' Hopkins to Buddy Guy and Eric Clapton. The Hot Plate works the Deville like a good dog works cattle; it puts it right where I want it. My favorate is to play the guitar, with the Juicer on, into the amp set to where the output tubes are just going into overdrive, sweet clean rythem. Step on the Screamer and the Deville is hollerin' for it's mama, but at a sound level that is acceptable to the neighbors. My tone is not degraded. I find that the quality of sound is exactly the same as without the Hot Plate.

Tought, rugged, and dependable.

The people at THD are the kind of people you would like to call up just to have a conversation with. Frindly, cheerful, informative, and seem to be genuinely glad to hear from you, even if you do have a problem. I had my Hot Plate for 4+ years when it started having a volumn problem. I called THD, they said send it in. I did. They fixed it. I had it back in a week, and they DIDN'T CHARGE ME A DIME.

The Hot Plate is the only attenuator I have ever owned. In fact it is the only attenuator I've ever looked at. I read some articals in which Mike Soldano was raving about it, so, I figured it must be good. He was right, and I am happy. If it were lost or stolen I would replace it with another just like it. I play guitar for pure pleasure. It helps me stay sane. Thanks to the Hot Plate I can be in my little guitar room playing through an amp that is so distorted that it's sweating and my wife can be in the living room watching TV and not be bothered by the noise. That, sir, is happiness.

Easy to use!
I set it at the highest attenuation when I first hooked it up just to hear how quiet it could go, then turned it up slowy to hear the tone difference. With the line level out, the fan, the noise reduction curcuit and the high/low compensation eq switches it deserves a 10 for being well thought out.

I use this 8 Ohm model with an unmodified 1971 Marshall Superlead with a tube Varidrive pedal in front of it. The Varidrive used sparingly, just to give it a little more thickness (mids cranked on the pedal).
I feed the output of the Hotplate to a 16 Ohm Marshall 1960TV (extra tall) basket weave grill cabinet, loaded with 25 watt greenbacks. Apparently, running a higher Ohm cab smooths the highs out a little bit, which is fine by me, I go for thick mids.
I was actually impressed by the sound with the atenuation at -16 dB, I was expecting worse by some reviews that state it sounds really colored at -12dB or less. The high and low switches work well at low volumes. But when I set the Hotplate to -8dB it really sounded amazing, too loud for most small clubs though, -12 dB is what is needed to play clubs with my rig. Minus the speaker crunch you get at high volumes, this unit is 90% transparent and the color it adds, I actually like it!
I've heard other heads like mine with a Hotplate and knew I would love it before I bought it. I just had to convince myself to part with the money to spring for one. I am very happy I did!
If your amp sounds great cranked it will sound great with this for sure. If your not happy with the Hotplate try it on another amp. I can't see it being this units fault.

Heard great things about THD's products and customer service.
IT IS SOLID and it gets pretty HOT!

I'm not gonna call them and bug them, seems like everyone else is.
I don't know how they keep up with all the inquiries.
Leave them alone, let them build stuff!
I'll give them a 10 for answering everybody else's questions!

I play rock. I love the guitar sound from Stone Temple Pilots, Van Halen (old), John Sykes, Led Zeppelin, etc....This unit is a god-send for my recordings!
I wouldn't be able to get these tones if it wasn't for this unit.
A Marshall Superlead rips your head off, when cranked it's brutal! It's so loud damn loud!...I don't know how you can tell if your tone is good or not, it's just a wall of GGGGRRRRR...I don't need my hearing damaged thank you!
This is the answer. It just sounds amazing! I'm very happy!

BTW: I was looking into another attenuator, the Mass 100 made by Weber VST which has been getting some great reviews.
I have to give Ted alot of credit for being honest with me!
He said that the Mass 100 couldn't handle the heat produced by an old Marshall. Though it's a 100 watt head, it can actually put out 130 watts at full power. The Mass 100 couldn't handle that much heat without having to cool down every once in a while. Ted at Weber VST gives great customer service too, the same as THD. I believe both companies make the best attenuators hands down. But the THD Hotplate suits my needs the best.

Using the unit is easy, just put it in the box and leave it there, and never ever hook it up to your amp.

Has everyone gone crazy ... I read the reviews and thought I'd try one, boy was I disappointed. All it does is suck up your tone, all of that beautiful tube harmonic distortion is totally lost - so the thing you're trying to achieve in the first place by turning up is negated by the hot plate. What a joke - turn up and wear earplugs!

Used it for one hour I don't have an opinion on it's reliability.

Would recommend not wasting your time ... if you are a true tone purist like me you will want to make an espresso maker out of this after you try it.

Equipment used: Fender Hot-Rod Deluxe w/Svetlana 6L6's and Sovtek 5751's in V1 & V2, GrooveTubes 12AT7 in V3 (phase inverter.) Fender American Stratocaster w/EMG DG-20 pickup set. Custom Warmoth Strat with hollow body & Lindy Fralin Blues-Special pickups. Fender 3150R pure nickel wound strings.

I bought this because I have a Fender Hot-Rod Deluxe, and as users here will attest, it is VERY loud for a 40W amp! Since I live in an aparment, I needed to keep the level down.

The first thing I noticed, (and loved!), was the ability to get power-amp distortion out of my amp! Since I've never been able to crank my amp up that high, I've never heard it. Now I can! Turn the clean channel all the way up and put the Hotplate on -16db, then adjust to second attenuator knob to the desired listening level. VIOLA! SWEET POWER-AMP DISTORTION! Play harder, and it distorts more. Back off your attack, and it cleans up. THIS is what a tube amp is SUPPOSED to do! The amp sounds chimey and alive, not fuzzy. (And your neighbors won't call the cops on you any more for being too loud.) Turn your amp's master down to about half, and switch the Hotplate to -12db, and you have plenty of clean headroom. The bright and deep switches are good for correcting some of the failings of the Hot-Rod Deluxe, which is known to be a bit "bass-heavy."

Switch the Hotplate to LOAD and plug the line-out to your board, recorder or computer, and you can record silently, use the it to drive the front-end of another amp, or even listen with headphones, (you'll need a mono-stereo converter or you just get the left channel.)

This thing is GREAT! Now you can get that sweet power-amp distortion without pissing-off your neighbors or your sound-engineer.

Power amp input. Speaker outputs (2), Line-level out with volume knob, Attenuation, (-0db, -4db, -8db, -12db, -16db to infinity, Load only>) Bright (Treble) switch, Deep (Bass) switch, Noise reduction, (with a light that shows it's active, which can be switched off.) Internal self-powered fan, (for cooling.)

Since each version of the Hotplate is tailored to the output impedence of your amp/speakers, make SURE you get the correct one! (8 Ohm if your amp has an 8 Ohm speaker, 16 Ohm if you have a 16 Ohm speaker, etc.)

No problems yet. There isn't much to break down in this thing. It's mainly just a series of capacitors and inductors. It's housed in a heavy aluminum chassis that doubles as the heat-sink. I suppose one of them could go bad, but how often does that happen? The main weak points for failure would be the knobs (pots), the input jacks or the cooling fan.

Haven't needed it yet.

I've been playing about 15 years, and play mostly classic rock and blues.
If this were lost, I'd definitely buy a new one. If it were stolen, I'd hunt the dirty rotten theif down!
There really is nothing else that compares to this out there. Marshall had the Power-Brake, but I hear that they were plagued with problems and eventually discontinued.
The only thing I wish this had would be one version for all impedence values, but I suppose that would make it about 4 times larger and 4 times more expensive.

If you have a tube amp you NEED one of these! (Unless you only play large venues and can play at full volume, and how many of us do that.) If you want that sweet power-amp distortion from your amp without bleeding from your ears and going deaf, this is it!!!

Plug it in, adjust the attenuation as desired. Even an old lady could operate this thing.

I am using this with a Rivera R55-12. Since the amp is running harder, there is a bit more hiss when the gain is up and the master is around 7.5 - where it sounds sweet. It's not really a problem though. I have always loved EVH's tone circa 1984 and have tried to get that vibe but not duplcate it. I don't want to sound like anyone specific, but I've learned what other players use to get their tone so that I can shape mine to reflect my own sound.

I like a rig with a core tone that inspires. I constantly messed with the Rivera until I bought the Hot Plate. Now, I know what I was missing - the power tube burn. If you've ever experienced the sonic orgasm that only sizzling tubes can create - you know what I mean. If you haven't, you don't know what your missing.

The comments about the Hot Plate coloring the tone is true to some extent. But if the tone gets better because of the coloring - then the change was a good thing. At practice or stage volume, the Hot Plate is awesome. If you're playing a bedroom levels - let's face it - it ain't gonna sound the same, but its close. Besides, you don't do any serious playing/recording at real low volumes anyway, so who really cares if it's not exactly the same as on higher settings. I like the -8 dB setting the best for overall tone - but that's loud enough to shake the walls.

I can't believe I waited this long to buy what I consider to be the most important addition to my rig.

I bought this used, and it works fine....

Haven't used it yet...

I play mostly harder edged rock with blues influences. A friend of mine called my style Eddie Ray Lynch - I guess that sums it up. I've been playing for (damn I'm getting old) 26 years and own 5 guitars, a few pedals and my Rivera running through a custom 2-12 cabinet with V30's. I like to keep it simple - my rack days are over. I won't run another tube amp without a power attenuator - now that I finally have.

I used this with a torres super texan and a curzon american classic.Works great.Much better than that dreadful power brake thing.I can set the clean channel to break-up "just on the edge" and then drop the volume down with the THD.It still sounds good not like a master volume.The bright/deep switches are useful and work well.No attenuator will ever sound EXACTLY like an amp at full song but this is very close.I actualy like the slight compression it gives.

From left-right load level' bright switch' bulbs on /off' deep'variable pot when load is set to-16db
Rear input/line output jack sockets line out level control 2 speaker outs.Finished in a very pretty anodised purple case.big 8 ohm logo on the rear auto cooling fan.Take care with that pretty finish!! Basically all you need.

Bulbs light failed so only a seven .It still works without it

Ring em' up .they're pleasant 'Instructions enough for most.

I play regulaly and would replace this if stolen at #209 ouch!!!

Setting the unit up was easy. The only thing I wish I would have understood was how the LINE OUT worked. I bought this item used, and I was hoping to feed the line out directly into my computer's sound card. After emailing THD, (Ed responded within hours :-), I found out that the line out required a speaker emulator. Oh. well! I connected within minutes to my amplifier. The manual, while only a few pages in length, is concise. MAKE SURE THE IMPEDANCE OF THE HOTPLATE MATCHES THE IMPEDANCE SETTING OF YOU AMP AND SPEAKERS. I would email THD with any questions BEFORE purchasing the hotplate if you are unsure about the impedance of your system.

The front of the unit has an attenuation selector (0 db, -4 db, -8 db, -12 db, -16 db, and LOAD). In the -16 db position, a "fine tune" attenuation pot becomes active to allow you to dial in a volume level. I REALLY like the "fine tune" pot for the -16 db position.

There are also to tone switches. One labeled 'BRIGHT" and one labeled "DEEP". The switch allows you to tailor the Trebel and Bass response at the different attenuation settings. Nice feature that works well.

There are two SPEAKER OUT connections, a LINE OUT (as mentioned above) and a LINE OUT level pot. I believe the LINE OUT could be run to the instrument input of another amp, but I haven't tried this yet.

There is also a noise reduction circuit that can be switched in and out. I must confess I can't notice a huge difference.

There is a cooling fan integrated into the base of the hotplate that activates from the power drained off the amp. Nice feature.

It seems to mee that the people at THD took their time to get this unit designed and constructed as well as possible. I haven't tried another other type of power soak to compare this to, however based on the buzz about this unit, I decided to give it a try. I am NOT disappointed. As mentioned above, I wish I would have understood the line out better, but I should have asked about its function first.

Another not. This unit is desinged to work with valve style amps only. (Valves in the power stage). Again email THD with any questions, they seem more than willing to answer any questions.

I am using this with a 1980 Marshall JMP 50 watt MK II combo tube head, 2 Celestion G12-65 speakers. The amp is a master volume, so one might question why I would use a hotplate to get the extra power tube distortion. Well, I just wanted to. I also have a Boss CS-2 compressor and an old Ross 10 band EQ in the instrument line.

I couldn't be happier with the sound. Again, I haven't tried other power soaks, but based on the tone I can get from the Hotplate, I don't think I want to.

I have a 1983 Ibanez Roadstar II with a old DiMarzio Dual Sound in the Bridge and a stock humbucker in the Neck. This set up give me all the gain I would ever want.

There appear to be alot of tones here, and I'm still working on getting them all.

I need to get new tubes and a bias job, as I haven't ever had it done. (I bought the amp in 84, still using the orignal EL34's) On high amp volume settings, it gets kinda fizzy, but I think a tube and bias would correct that.

With the PRE on 10 and the master on 6, I'm in tone heaven!!

As I mentioned above, THD has designed what appears to be a very rugged, reliable, and quality piece of gear. I am so impressed that I believe a BiValve is in my future! My hats off to the guys at THD. NICE JOB!!

They have always answer my emails pomptly and completely. Again, hats off to them. This kind of customer service is hard to find anywhere!

I bought this unit off of EBAY, and I feel I got a fantastic bargin. It works great with my Master Volume amp, and if I had a non-master volume amp, I would consider this unit almost essential. I couldn't be happier with my Hotplate!!

I use it with Divine sounding Ashdown Peacemaker 40, class A all tube 112 three channel combo that weighs only 34lbs ... !

I can say that the hotplate does exactly what THD claim i.e.
reduces the power witout coloring the sound, so that I can now
play my Ashdown at ''11'' and get a singing distortion of the
power tubes - GREAT; also fabulous for sweet blues ...

Combined pre-amp and power-amp tube distortion is simply beyond words so every true guitarist should buy one :-)

As described by others wh use 16ohm hotplates.
Basically you set it at -16dB and then arrange your
finall sound with power valves singing 100% :-)

Easy to set up: 1 minute.

brand new :-)

They replied to my mails (Ed that is :-)

I play since 1960 and buy only the very best gear: this unit together with Ayan Enterprises Smooth & Slim is one of THE
secrets of a great tone, IF you know to play well :-)

In summary, if you after THE tone - buy one !

Really easy, couldn't be simpler, just select the attenuation and off you go

I use a PRS Mcarty, or one of several Strats or Strat clones, and I can get the great Mesa/Boogie distortion at bedroom levels without my wife going nuts or the neighbors complaining. I've not noticed any major coloration, the bright and deep switches help limit this in my opinion.

No problem, no power supply, looks like you could runa truck over it.

Haven't had to try

I'm very much an amatuer, but try and play some blues and rock.
I bought mine Mail Order from Steve's Music in Rock Hill NY, he's greta to deal with.

This unit is very easy to use. You only need to realize how the attenuation controls on the front function...then you're all set. The bright and deep switches work to put some of the frequencies back in that are "lost" in extreme attenuation.

I'm using it with several amps Budda superdrive 30 (PTP :)!) and older non master volumes....with the budda it works well, but you also realize that an attenuator is not a miracle. It does reduce the volume from your speaker, but you realize how much a certain level of volume and speaker "push" is a part of good tone. I think it works with a master volume amp, but it is a little tricky, you want to attenuate as little as possible, and balance between the master and the attenuation...like -8db and vol at 75% will work well but is still certainly not quiet. I would reccomend it for really high power non master amps (plexi-etc)as totally indespensible, really the only solution besides pulling tubes. For lower watt and master volume a helpful tool, but not as necessary. I give it a 7 only because it can only do what an attenuator does. I mean as far as attenuators go its a 10, but to reflect that none are perfect it's a 7.

It seems vey reliable....well built...heavy duty pots, jacks etc. makes me want to see some of their old (non-univalve) amps. There are light bulbs which work with the noise reduction circuit. They are replaced as needed.

Incredible...reallly....just the best I've ever encountered...I had bought one which was apparently used and missing the rubber "feet"...well I called THD and Ed helped me out. He was very nice and explained that it didn't matter how it was bought and that anything I needed they would help with... totally above and beyond expectations...really stellar service...

Really what motivatd me to post this is the amazing service Ed and the others at THD showed. They seem to be a model for customer support. Overall just an outstanding experience dealing with them. I am more interested now in the rest of their line after this positive experience.

Very straight forward and easy to use. Because you can blow up your amp very easily, I was extra careful setting it up. I actually tried the set up on a older (and less expensive) amp first as a experiment. Controls are pretty basic and easy to figure out. Instruction sheet was very helpful. You have to make sure you buy the right unit for the speakers you are using, otherwise amp damage will occur. You cannot use this unit with a soldi state amp

Sound quality is very good. I am using a Marshall TSL 122 with the hotplate unit. The gain controls on my amp are very dynamic as well as the lead and crunch channels. When driving the power stge of the amp with the master volume controls, I have to cut way back on the preamp gain, otherwisw to sound gets too messed up sounding. Through a distortion unit into the chain and things get really crappy sounding. you get a real nice grind with it if you cut back on the preamp gain. I like using the clean channel with my distortion units and crank the gain up to 10. That drives the power stage hard and really helps my distortion unit sound really good. The noise reduction circuits that are built in, work very well. the unit is very quiet.

Unit looks tough as hell. It performs as advertised. The unit dissapates heat very well. It seems that my amp runs cooler with the unit at 10 than without it set at 3.

Just got the unit last week, no opinion. I bought the unit form the Plexi Place in CA. When I ordered the unit the sales person aked me a bunch of general questions as to what I was going to do with the unit what type of amp I had, etc. They seem to endorse their product pretty good, so they like to know how it will be used to give feedback to other buyers, I guess.

I play mainly hard rock and it is hard for me to drive the power amp stage into distortion, so this unit is perfect for those folks who have a big amp but never get to drive it hard. You can get great sounds out of it with some experimenting and tweaking. I should have bought one of these a long time ago.

I'm using this with a SF Fender Deluxe Reverb. Though it's already a low powered amp, I do play rooms where I can't turn it up enough to hit the sweet spot -- that special place on the volume knob where it's equal parts distortion and definition. The Hot Plate allows me to produce that sound in any size room. Beautiful, full-bodied, "touch of power tube break-up" at almost any volume.
I love my amp's best sound; the Hot Plate lets me get that anywhere I play.

I won't detail the features here; most of you are probably more familiar with them than I am, anyway.

Bought this used, and it's worked perfectly for me so far. There's no AC, so I'm guessing there's less to go wrong. I know THD has a strong reputation for reliability.

Another area where THD really shines. I cold-called the company hoping to get a little product info, and wound up talking tone for twenty minutes with the company's president, Andy Marshall. More than helpful, he seemed down right INTERESTED in what I had to say, and I've never been more impressed with a music manufacturer's phone support.

If you like your sound, but wish you had a little more 'volume versatility', this might be the product for you. It's probably designed to be used with more powerful amps, but it works perfectly with my Deluxe. Now I don't have to tolerate the artificial sound of a pedal to get a bit of break-up at lower volumes. Great product, great service......... hats off to the fine folks at THD.

Very simple. Just plug it in with proper power cords, NOT PRE-AMP CORDS, between the amp and speaker.

I think it sounds incredible. I shopped around and was amazed at how well this product works with almost no tone loss. You have to use a proper cable designed for power though. There is a difference.

Built like a tank.

I never needed customer support.

If you want to overdrive any amp at reasonable listening volumes, this is the best thing I've ever seen. You definitely keep it for life. I use it on a Groove Tube Soul-o-75. It sounds incredible.

the hotplate is an attenuator designed to allow you to crank your tube amp to stage levels and then attenuate the volume down to usable levels. the hotplate accomplishes this by using a series of load resistors and other components that are used to dissipate the power of the amp--part of this is done via a fan that is activated by the output of the amp, and part of this is done through a lamp which also acts as part of a noise-reduction filter.
operation is very simple. there are basically two knobs and two mini-switches on the front of the unit. one knob is an attenuation knob that increases attenuation in discrete steps of 4dB--there are settings for 0dB, -4dB, -8dB, -12dB, -16dB, and load. when the control is set to the -16dB setting, the second knob becomes active--this second knob is a continuously variable attenuation knob that allows you to dial in anywhere from -16dB of attenuation to full attenuation. with the left control set at "load," you can completely unplug the speakers from the amp and use the amp as a giant fuzztone into a power amp or into another amp. the two mini-switches activate "deep" and "bright" boosts, and are useful for adding back both low and high end when heavy attenuation is used. evidently, this compensates for the ear's tendency to hear less lows and highs when the volume is very low and works very similar to the loudness control on a home stereo system.
there are four jacks in the amp. one is for the input from the amp, while there are two speaker output jacks. the last jack is a line out, which is also accompanied by a knob for setting the line-out level--this allows you to slave your amp into another amp or power amp. the deep and bright switches are interactive with the line-out, however: engaging the deep or bright switch will cause a DECREASE in deepness and brightness in the line-out signal. be sure to look at the jacks carefully--you can do some very major damage if you mix up the jacks. also, be sure to use very high-quality SPEAKER cable when connecting the hotplate--using an instrument cable will fry the cable and will likely damage your amp, the hotplate, and perhaps your speakers, as well.
the manual is very well-written and comprehensive.
one more thing...the hotplates are designed to work with specific impedances. you CAN use them with different impedances, but ONLY if the speaker cabinet you're using is rated at a HIGHER impedance than the hotplate. in any event, the amp should be set at the hotplate's impedance level or LOWER--setting the amp any higher than the hotplate's impedance level will nuke the unit.

the THD gives me mixed feelings. every single attenuator colors the tone of the amp, and the hotplate is no different. no matter where the attenuator is set, there is some coloration, though the deep and bright switches help to offset this effect. however, i can honestly say that even at -4dB, there is enough coloration to make a difference--specifically, there is a loss of both high and low end, and i would liken the tonal effects as to having several sheets over the speaker. the bright boost adds a bit of scritchy top-end to the tone, and it's not a frequency that i like very much--the deep switch is more effective. THD has designed these switches well, however, in the sense that they INCREASE in effect as you INCREASE the attenuation. the hotplate works very effectively at what it's supposed to do, but there is a tonal compromise. in the future, i'll continue to bring the hotplate to gigs, but if i have the opportunity, i won't be attenuating. i hate to give this analogy, but using the hotplate is in many ways like using a condom. it's still the same in many ways, but you do lose something.
as far as tone and sound quality goes, i've heard many times that the maximum attenuation threshold on the THD is about -8dB before you really start to lose tone. that's about right--after -8dB, you do get some severe tonal coloration. bear in mind that these units were meant to tame extremely loud amps such as marshall plexis down to CLUB-approved volume levels. while you can actually tame a 100-watt tube head down to bedroom levels, there is a severe loss in tone when you do that, so keep that in mind. compared to the other units available out there, such as the scholz power soak and the marshall powerbrake, the THD is clearly superior, though it definitely does color the tone. i'd be interested in hearing the kendrick airbrake if i could get my hands on one.

look solid as a rock. the casing is very heavy-duty, and the components inside look top-notch. i wouldn't worry about gigging with it.

i've talked with THD's owner, andy marshall, once, and he was very helpful and knowledge. he was also very patient in answering my questions and gave me some guidelines for using the unit.

overall, i'd say the THD does what it does well. my opinion is that it tends to work better on non-master volume amps, as using it with master-volume amps tends to introduce yet another control valve for the amp. the attenuator with a master volume-equipped amp is in many ways like adding another attachment on your garden hose--you can't not expect that to color the tone. on the other hand, with a non-master volume amp, these units work great. you can use the hotplate on a marshall plexi or an old fender amp and get the wonderful power-tube distortion tones without losing your hearing or getting thrown out of the club.
if i had to buy it again, i'd do it again, but i'd limit the use to non-master volume amps.