THD UniValve Head

Nice set of features for a simple amp. Not cheap, but well built and unique in what it offers. I use it with a preamp and effects unit. Wish it had an effects loop. Plenty of power.

Use it with a Tele (5-way switching), Gibson LP double cutaway with P-90s, and Tele HH with Duncan SH2n and SH4 pickups.
Overall sound stock is not very good - excess of treble and some nasty breakup scratchy sounds when you drive it hard. In the clean settings its OK, but lacks full sound. I eventually made serious mods to the circuit.
Check out my mod at http://sites.google.com/site/stringsandfrets/Home
The result is absolutely stunning - the amp performs beautifully. If you have a Univalve and you're not happy - try the mod - its so worth your time.

Seems reliable - well built in many respects. There were some issues with the Hot Plate control getting dirty and noisy, but I've cleaned it once (per THD service bulletin) and it's been fine since. I've had the amp for over 3 years.

Reasonable. I wish THD were more open about the circuit schematics. I have searched for them and finally just dissected it myself. They could have saved me a lot of time.

Now that the amp is modified, I would not trade it for anything I've ever heard or played through. Again, see my pages for info on the mod
http://sites.google.com/site/stringsandfrets/Home

Its pricey new, but there are a number for sale used now that you can get for less. It's worth picking one up if you do the mods.

Unsure of year, but serial is 1352. I have owned my Univalve for 12 months now and am ready to write a report.

I play all types of guitar music and have owned a raft of lesser amps - Marshalls, Fenders, Roland, TubeWorks - nothing comes close to this class A single-ended beauty. I consider it a serious musicians tool, not something that will give the instant gratification many manufacturers need to push.

The controls are adequate for the purpose - but you have to spend time learning the amp and to get the best out of your guitar and speaker combination, try different valve combinations - no other valve amp has this flexibility.

I use two guitars:
Electric is a PRS Custom 24 with a Dragon in the neck position and HFS in the bridge (I used to own five guitars - Gibson, Fender, Ibanez however after owning the PRS for 2 months I discovered I only need one electric guitar)

Takamine - sorry forget the model - 6 string acoustic with piezo pickup.

I have several effects but generally only use a MI Audio Neo Fuzz (buy one!).

I use high quality Mogami cables with Neutrik connectors.

This amp makes no noise - even fully cranked....

Sound depends on the type of tubes you choose to use, also the speaker cabinet.

Some combinations I like:
Want it clean - ECC81's for INPUT and DRIVER, 5881/6L6CG for POWER
Want it dirtier - ECC81's for INPUT and DRIVER, EL34/EL84 for POWER
Want it woody - 12AX7 for INPUT, ECC81 for DRIVER, 5881 for POWER
Want it woody/dirt - same as above but sub EL34 for power
Want it Yum - 5751 for INPUT, ECC81 for DRIVER, 6L6CG fo POWER

I don't enjoy the sound through an open backed cabinet is much as the sound from a sealed cabinet.

Clean is wonderful, distortion is crystal clear - even at high volumes, you can hear each note of highly distored chords - this is the nature of class A.

Many people comment that this is the best sounding amplifier for my acoustic guitar - really is magical and through the Univalve actually sounds like an acoustic guitar! This again is the nature of Class A - it is pefectly suited to the anomalies of acoustic guitars.

You have to learn how to use this device.

All I can say is one night, mid-gig, mid-song, I felt the rhythm guitarist trip over whilst doing his silly Pete Townsend imitation and turned around in time to see my 2x12 cabinet, with UNIVALVE atop falling over forward.

The amplifier hit the floor from nearly 3 feet up. It bounced. A peculiar fart was emitted from the speakers, and we kept playing. The Roadie picked up the speaker cabinet and left the THD on the floor, upside down, while we finished the last 40 seconds of the song.

At the end of the song, we picked everything up - all still powered up and running, put the amp ack on top of the cabinet, and got into the next song.

That was eight months ago. I found that one of the valves used in that 'experiment' died soon after and was buried with full military honours. The amp didn't seem to suffer any consequences.

I dropped a Marshall from 6" once getting it out of the car and it cost over $180 to get repaired.

Never had to deal with THD.

My tech did a review when I purchased it and recommended I purchase a new 12ax7. No issues h could see.

Been playing for over 30 years.

If someone steals it and I find them, we'll be having our own, very special "Good Friday". Then I would sell their hair to a wig maker and use the proceeds to immediately purchase another Univalve.

I had tried a Mesa Boogie and Ampeg - both were nice, but I found the Univalve had so much variety through the ability to instantly change a valve. There was NO COMPARISON with new Marshalls or Fenders I tried - but hey, brand and image is everything in the big, wide, wonderful music instrument industry!

The only thing I would change would be to include a footswitch for selecting high or low impedance inputs.

Serial number 1681. The amp debuted in 2001 to positive reviews. I picked this one up used, in excellent condition in 2008 from a private party. Featurewise, it's Class A, single ended with the unique (as far as I know) ability to accommodate a variety of preamp and power tubes without the need for rebiasing. In my book, you can't get any more versatile.

I've read the other reviews and I'm baffled by the negative (harsh) comments. In fairness, I play my amps as clean as possible, preferring distorting pedals to ad whatever "grit" I need at any particular time. So here's my setup: mostly single coil, Fender-style guitars (my current favorite is a Warmoth Fender with Fender noiseless cobalt PUs) straight into this amplifier's "Roll" input (low gain) without the attenuator active, High Voltage, "Attitude" at 12 o'clock, volume at nine, treble at 3 (this is a really bright Strat) and the bass at nine. It's like an eargasm. That means an orgasm for your ears. Duh. Crystalline, warm, three-dimensional, living and breathing notes spilling out of this thing in a way that makes every other amp I've ever owned sound flat and brittle, including my prized Fender Pro Reverb. I confess. I don't even know what kind of tubes are in this thing at the moment. It sounds incredible. Fantastic. Unbelievable. Spine-chilling. Warm, Breathy. I could sell every other amp I own (I started doing so today, after playing through this amplifier) and be perfectly happy.

Seems well built. No reason to think it's not reliable, but I can't offer an opinion on this topic.

No opinion. Buzz seems pretty positive on THD in general.

I've owned a lot of amps. I tend to buy, sell, buy, sell and buy, then sell. This one's a keeper.

Simple design with some twists. Low and high inputs, volume, treble, bass, "attitude" knob (adjusts the signal strength to the driver tube),full power/attenuator switch, the attenuator control, which is actually a THD Hot Plate (think Marshall Power Brake), hi & lo voltage switch, and a simple (but effective) noise reduction circuit. On/standby switch, and of course, mains power switch. Rear panel consists of speaker out jack, switch to toggle between 2/4 ohm, and 8/16 ohm speaker loads. Also a line out jack with its own level control. Single channel, no FX loop. Amp has the ability to accept any octal based power tube (6L6, EL34, 5881, KT66, KT77, KT88, KT90, 6CA7, 6550, and even 6V6,(amp must be set on lo voltage), and an EL84, with a yellow jacket adapter. Also, any 9 pin tube can be used for the pre-amp, and driver tubes, such as 12AX7, 12AU7, 12AT7, ECC83, etc. All this adjustability to tailor the overall character and response of the amp.

Well, this is where it gets harsh, literally. This is the 2nd Univalve Ive owned, and I had forgotten why I sold the first one, but was reminded after owning this amp again. I really cant understand why players seem to be gushing over themselves about this amp. I tried at least 20 power tubes (some duplicates, like 3 or 4 different EL34's) and an equal amount of pre-amp/driver tubes, and though the amps character DID change, I was NEVER able to get rid of the harshness of the overdrive/distortion in this amp. Its not the speaker cab (2-12, half open, half closed back cab, with G12H-30 Celestions)that causes this. It might be transformers, it might just be circuit design. There really is no clean sound, unless the guitar is plugged into the low gain input, and then the amp sounds somewhat weak. Its strong enough in the high gain input, but again, harsh sounding, especially in the lower registers of the fingerboard. Its not that the amp necessarily sounds BAD, it just sounds dry, and "grainy", and excessively bright; the amp does lack bottom end, regardless of tube choice. I ALWAYS had to run the bass full up, and the treble basically at zero, or 9 o'clock position at best, and even then, the low end was barely acceptable. Once the attitude is turned up, the brightness increases even more, along with the aggressiveness of the amp. Its an appropriately named control. It is a fairly loud amp, and it has a LOT of gain, just not quality gain IMO. The attenuator and the noise reduction work as advertised, but decrease the responsiveness, and attack of the amp considerably. Hi/low volt switch cuts the output approx in half, and also knocks down the responsiveness.

No reliability issues. It does seem to be built very well.

I spoke to Andy Marshall (THD amp designer) and he seemed very friendly and helpful. He recommended trying KT66, or KT88 tubes, which I did. Neither cured the harshness, or lack of bottom end punch.

Ive played guitar for 35 years, and have owned a LOT of different amps and guitars. Quite honestly, Im selling this amp this coming weekend, and I cant wait to get rid of it, and would NEVER buy another one. Im not opposed to trying other models of THD amps, such as the Flexi-50, but the Univalve is something I wont buy again. (and I got this amp DIRT cheap, at Guitar Center when they had an inventory clearance). There was a reason this amp wouldnt sell, at any more than what I paid for it, because no one liked the way it sounded. Im firmly convinced that there was nothing actually WRONG with this amp, as my previous Univalve had the same grainy tonality. Its just the nature of this amp.

This amp has one channel but it has a two inputs, one of which adds a gain stage for those who play with a lot of distortion (or weak pickups). You cannot AB the inputs because when you are plugged into the low gain input it defeats the high gain stage or something like that. There is no effects loop or headphone jack which would both be nice, but there is a switchable line/instrument out with a volume control, and when no speaker is plugged in, the amp supplies a dummy load, so it could easily be run into a headphone or practice amp, or your stereo's aux in, or any higher powered slave for that matter. You could plug it straight into a Twin. It has a Hot Plate -- kind of like a power soak -- which works best at mid volume, but gets a little tinny when you really crank it down. The amp can run any octal ouput tube with the same pin-out as a 6L6 (6V6 up to 6550), so you can fiddle with the ouput power and tone, and with an efficient speaker it would be loud enough for small clubs with the stock EL34, but I'd just recommend getting the tone you want and running the line out or a mic to the house system.

The features I was looking for in an amp were flexible tone, tube overdrive regardless of volume, and NO hiss or hum. I have vowed never to carry anything heavier than 30 lbs again, so I didn't want a combo. My favorite time to play is late at night, and when I am not playing a note, I DONT WANT TO KNOW THE AMP IS THERE, just like when you pause a CD player, you don't want to hear your stereo making extraneous noises. I tried new Vox and Line 6 modeling amps and tube amps. The modeling amps with a 12AX7 seemed good at first, but then I could hear the hiss being gated out. I also tried the new Fender Princeton Recording Amp and was impressed with the features. Any of these would have been good choices for playing live, but all failed the hiss test. I wound up buying the Univalve because it passed the NO hiss test (there is a noise reduction switch that is not a gate) and the tube overdrive criteria, but I had to do some experimenting to get the flexible tone.

There is really only one feature I wish this amp had that I can't invent a workaround for, and that is a drive control to let you adjust the amount of gain you are adding if you use the high gain input, so for now I don't use it, but I haven't tried any tube substitutions yet.

You will never get through all the sounds this amp can make once you start substituting preamp and power tubes. Plugged into the high gain input, noise reduction off and cranked you can make this amp a little more noisy, but nothing like a Mesa -- sorry, but NO hiss was one of my main criteria here, so there isn't much to criticize.

The amp is heavier on the mids than I like for playing either bright jazz or funk rhythm, but just right for lead. At first I thought I was going to have to use a second amp for rhythm, but I solved my problem as follows. My pickups are active EMGs on a strat. I plugged into the low gain input, turned the amp all the way up and set the controls for a good searing lead. Then I put a Danelectro Fish&Chips graphic EQ pedal between the guitar and amp (read the Harmony Central review on this little cutie), cut the mids out and dropped the master gain on the pedal for a 10 - 15 dB cut, just the amount I needed to dial back for clean rhythm tone. If your pickups aren't as hot as my EMGs, you could probably do the same routine in the high gain channel. The result is just like channel switching, EQ in for rhythm, EQ out for lead. You can use the hot plate to adjust overall volume.

I would use it without a backup. The tubes and controls are mounted on the chassis, but this amp does have printed circuit boards in it. Things are spaced out nicely inside, and power resistors are up off the board. I prefer point to point wiring but that would put it way out of my price range. My compromise will be just to open it up once in a while for the first few years and make sure the circuit board isn't getting brown (heat damage).

I bought this amp used on craigslist -- no warranty -- and had never played one before. I noticed that the hotplate cut out when the knob was turned all the way up. I called the Seattle factory and talked with the guy who designed the amp, Andy Marshall. He emailed me instructions on how to clean the rheostat complete with pictures. He offered just to do it for free if I brought the amp in. The instructions were good enough for me, but if you don't want to open your amp up, you could print them and take them to a tech.

If you take an amp back into the isolation room in your favorite music store you will learn more about it than you can on the show room floor with all those other players wanking on the Marshall Stacks. I have been playing since I was 10 and building amps since I was 12 (49 years old now). I have built and owned dozens of tube amps and I had pretty much come to believe that more gain stages equal more hiss. I cannot figure out how THD made such a NO hiss amp, so if I lost this one I would have to just buy another. Granted that I had to use a $40 pedal to make it act like a channel switching amp. I think my amp building days are over because of this one.

Great.....but no reverb! i give it a 10 because of the tube swapping and no biasing, which to me means no amp tech charging me money.

great tube saturation. i've been playing this amp for a year now, and i can tell you this: i've been the type to buy an amp play it for a year, sell it on ebay, buy a different amp and continue the same routine. i've been doing this for about 10 years now. i've had fender custom shop amps (bassbreaker) marshall jcm 800, ton's of blackface and silverface fenders, and many other amps. i always would get tired of the tone in a year or so and sell them in order to be able to afford another one. the only one i could not sell was a blackface twin that is the best twin i've ever heard (i've owned 6)
well a year later and i'm still in love with the tone that the thd gives me. if i get tired of the EL 34 sound hell i just throw in a 6l6 or a 5881. i will not be selling this amp, if a guy like me who is so fickle about tone can still fall in love with the tone every day for a year and not want to sell it, then that should speak volumes about the univalve. speaking of volume the 15 watts is perfect, i keep the volume turned all the way up and i'm never to loud but never get lost in the mix. you can hear some recordings i've made with the univalve at myspace.com/toddpirk all the songs on that site were recorded with the univalve. i used different tubes for each song too.

i give it a 8 b/c the light keeps blowing, bad fuse or something, but it does not affect anything it's just a light.

never dealt

been playing for 18 years, i think i will always be an owner of thd amps from now on, i love it! the price is just so good too, they could easily charge more for these amps and still sell them. i do wish at times it had reverb but thats what my fender twin is for i guess. great amp that univalve.

It has a lot of features, the hotplate is ok but as they all do at near max attenuation, robbs character severely. The lack of any loop on a techy sort of head like this bugged me to. You might think it would degrade the tone so it was left off? The hotplate should be left off too if that's the case. The high low inputs are vastly different in volume. While the high gives good volume, it's only good for a high gain tone. I have 5 watt amps that give twice the volume of the low gain input. If my ratings seem harsh, they're only in relation to the price of this amp.

It is a medium-to-high gain amp really and does little else worth mentioning. The tone was dissapointing and harsh, not musical at all. My array of 9 assorted power tubes changed the amount of gain but not that harsh, grainy honk. I have honestly gotten FAR tastier tube tone from a Sanamp Classic through a clean Fender Twin or Musicman RD50-112. That setup also takes a giant dump on the Univalve at speaking levels. I play Floyd Rose Mexistrats with USA electronics, Duncan little 59 HB's in the bridge pickup and Warmoth stainless steel fretted necks. I tried a ts808 with the Univalve which sounded OK but I was dissapointed that it was so much better than the amps tube grind. For the price and description, I didn't think I should need an OD pedal.

No problems at all. But I didn't keep it 2 months.

I've been playing over 30 years. I know classic tone, how to tweak knobs and adjust settings. I have several speaker and cab options. I tried everything. I loved and still love the look and portabillity of the THD amps. They look so damn cool but fell WAY short of my expectations in the tone department. The sound clips on the site were nothing like the actual tones available. I packed up my pile of new JJ's, the amp and the gigbag and sold it as fast as I could. I got my cash back before the word was out. I have owned Many tube amps, Mesa Mk3, Marshall DSL100, Fender Prosonic, Twin Reverb, Traynor yba-1, GK 250ml, and more. I have never unloaded any amp as fast as I unloaded that Univalve. My advice, try one first if you can or get a good price cause you might be selling it fast. It doesn't get good tone for the price, plain and simple. I doubt I'll ever try another THD amp.

The UniValve has 2 channels (Rock and Roll), but they are not switchable. Aside from that limitation, the amp is incredibly versatile, allowing you to freely interchange tubes (power and preamp) without rebiasing. The amp also has high and low voltage settings, as well as a built in THD Hotplate attenuator, so you have tremendous control over output level.

I own both the UniValve and BiValve, and they are my favorite amps of all time (and I've been playing for 30+ years). I cannot fathom how anyone could rate the UniValve low on "sound quality"! By experimenting with different combinations of power and preamp tubes, you can pretty much create whatever tone you like. No, it may not sound "exactly" like a Fender or "exactly" like a Marshall, but I don't care because I think it sounds better. And, if you should become tired of the Uni's tone, just change the tubes -- Fantastic. The UniValve (and BiValve) is also very responsive to pedals.

THD prides itself in state of the art PCB construction, and when you look inside, it appears every bit as well made as any boutique PTP amp I have ever seen. For 2 or 3 years now, I've played it 3 or 4 days per week, and have never had a problem. As an aside, it's also one of the most aesthetic amps I have ever seen -- sometimes I just want to stop and stare at it!

Playing classic rock 30+ years, and have owned too many amps and guitars, always looking for the perfect "tone." I've sold off a lot of good ones (vintage and boutique), but will never part with my UniValve (or BiValve). Moreover, at under a grand, this amp is a downright steal.

The 80 plus reviews here will give you the details here. I bought mine in 2006 with the Avatar cabinet deal. This is not my only tube amp-it fills a nice void with the features it has. I like the Hot Plate, I like the responsiveness of all the controls. Do not use the noise gate switch and yellow light at all.

They did switch the "THD" logo on the front from steel to white plastic. No big deal, but I liked the metal logo better...and yes you can put the top grill on with a KT88 in there.

I rarely use the "Roll" input. Sounds a bit thin with either my Strats or SG (or other humbucker equipped guitar). Big difference in volume between the two channels....i.e. if you leave volume at 'noon' setting, it is louder on the "Rock" input than the "Roll". No big deal. I run it with a JJ KT88 and JJ preamp tubes. This set up gives me a great Ronnie Wood Faces Strat tone and with a slight tweak, a great Duane Allman sound for slide and leads via the "Rock" channel. It does what my other tube amps do not. I have Groove Tube Soul-O 75 with GT6L6 GE tubes and a Savage Macht 6 with EH 6V6 and 5751's in it....so it fills in there. I also like it with EL34's-but not 6L6, 6V6 or the EL84's with the yellow jackets. Don't kill yourself buying and switching tubes like mad, I know that is the idea here with the Univalve-but pick a sound you can work with and go with it.

Very reliable and light. Be careful if you have kids, they can get their little fingers in there when you aren't looking! Tubes look cool to kids and the purple pre amp tube covers are tempting. No issues here. Have not had to change the little yellow/orange bulb.

Great. They forgot the power cord in mine when it shipped. Called Ed at THD, told him I got from Avatar (even if you do order through them, it ships direct from THD), he sent out next day. Never dealt with them other than that.

I love this amp. Fairly cheap for all the features you get for different applications. I would definitely check out the Avatar deal, their cabs are great for the money. I ended up running my GT Soul-o 75 through the Avatar 2x12, and now run the Univalve through a Mesa 1x12 3/4 back. Good for guys who have/want multiple amps...I just do not like the Roll input as much as the other. Maybe if I fiddled around with tubes all day, I would find a combination that would work for me using that input-I am sure I could.

Very versatile amp, you know the features

I guess it depends what you like. I found three combinations that were stunningly good, and a couple that were just average. Overall though it sounds great. You really have to tinker with it, it took me a week to find a combination that worked for me. I wish it had a master vol. I don't like the hotplate sound very much. Gives off a little hum, but nothing offensive noise-wise.

No problems. Excellent construction.

Very good support.

Great overall

If you're reading this then you're probably aware of the Uni's features. The big selling points for me were the self biasing and the built in Hotplate. The only thing I really wish it had is a mid control.

I'm currently using an Avatar 2x12 open back cab with a Celestion Alnico Blue and a G12H Anniversary. Guitars: Tom Anderson Cobra, Suhr Classic, G&L ASAT Z-3. It's tough to rate the sound of the Uni because it will accept almost any tube. I bought this amp without ever playing through it knowing(hoping) I could find my sound through experimenting with different tubes. Seemed like sound logic at the time. The Uni is very sensitive to tube changes so be prepared to do some experimenting of your own before you find the sound you're looking for. I have 2 or 3 tube combinations that I really like and I pretty much stick to those now. So, the sound...the Uni sounds wonderful from clean to mild overdrive, no problem there. If you don't normally play with a lot of overdrive this is a gorgeous amp, definitely lives up to the hype in this context, BUT...when you crank up the volume to the point were you start getting some power tube saturation things get a bit fizzy IMO. I've been searching for a good tube combination for heavy overdrive and I've had some success, but the fizz is always there. If I try to dial it out with the tone controls it ends up too dark. I suppose it could just be the nature of a class A amp. Whatever the case, I just don't care for the way this amp sounds overdriven, regardless of the tubes being used. I'm not the only one who's experinced this, visit Univalve.net and you'll find a lot of threads on this topic. My solution has been to use overdrive/boost pedals with a low/medium volume setting on the amp and it works nicely, but only after buying some pretty expensive pedals; Xotic RC and AC Booster, Xotic BB Preamp to name a few. I'd also like to mention the Hotplate because this is a feature that I had high hopes for. While it does a great job of allowing power tube overdrive at bedroom levels the tone is pretty far from what the amp sounds like with little or no attenuation, a bit of a let-down. I can't blame THD for this though. It's my understanding that it's the nature of the beast when using an attenuator. Bottom line is this: From clean to mild overdrive I give the Uni a solid 8. Crank up the volume and I give it a 6.

It rarely leaves my studio so I can't comment on it's road-worthyness, but it appears to be nicely overbuilt. Very sturdy metal chassis and cover. Feels very solid.

Never dealt with THD.

Ideally you'll want to grab a few different tubes and take the Uni for a test drive before you buy. Unfortunately that's not always possible. Again, IMO the Uni sounds great from clean to mild overdrive, especially with single coils. If you need more overdrive for hard rock/metal sounds the Uni may not be for you. The ability to use just about any tube is the Uni's big selling point and for just under $1K it's a good deal. It's very nicely constructed and one of the best looking amps I've ever seen.

This amp was manufactured in 2001. The serial is I belive #308. It is extremely well-built, although light enough to carry around in the NYC subway!

It has two channels, but no channel switching, no effect loop, no headphone jack, but it does not need any of that.

As it is known all around the world by now, this amp has the ability to take any octal-based power tubes (it has only one power tube socket) without re-biasing and it also takes any type of pre-amp tubes (two pre-amp tube sockets).

This amp is for experimenting and playing around with tube combinations til you find what you like. And you will like more than one combination for sure!

If you get 'tired' of one sound, go and switch all the tubes, or switch one tube, or two or all, and you will have something completely different coming out of the amp.

The amp has -in addition to two inputs (Rock and Roll), a volume knob, treble, bass, and attitude (it changes the edginess of the sound and your attack against the strings), it has a built-in attenuator, a built in and very hip-looking noise-reduction system, and a voltage switch to use with the different power tubes. The eq (treble and bass) are highly interactive, meaning that the more you turn them up the less middle you will have, the more you turn them down the more middle you will find. So the middle frequencies are managed through the tactful interaction between treble and bass.

I would like to change nothing in this amp, nothing at all. It is just what I wanted and needed. Nothing more, but nothing less.

I play/record/produce experimental Latin Rock mostly, though I usually gig backing up other artists. The amp suits everything that I play and more.

The rock channel is for louder, edgier, noisier applications. The roll channel is for the quieter, cleaner, chimmier stuff. Both channels are ideal for recording.

15 watts of pure Class-A tube power is pretty loud! Don't be fooled by the wattage. 15 watts is not quiet at all.

I wish it had a volume/master volume setup to drive the pre tubes for more variety. I wish it had a effects loop, you would think a kinda techy, frilly amp like this would. The amp is light and quite nice looking, The hotplate works well at reasonable attenuation.

The roll or clean channel is nice and likes pedals a lot but it only achieves about half the volume of the rock or gain channel. I would have probably liked this amp much more if the roll channel had more headroom. The rock side is slow and spongey with not much headroom or articulation. Not at all plexi like. It's closer to a cranked tweed deluxe sound. I have owned many near top shelf amps in this price range, Marshall DSL 100, Fender Prosonic, Mesa MK3, 70's twin Reverbs, Traynor YBA1 Bassmaster. The Univalve is not worth any rave in the sound category for the price.

Honestly, if you want a great low to medium volume plexi rock tone at an affordable price, get the cleanest sounding, loud and punchy old {70's Twin Reverb, 60's Sunn, 70's Traynor, or 70's Ampeg) tube amp you can find. Then get a Tech21 Sansamp (original or classic only). Many guys also swear by the Roland JC120 with the Sansamp because it's a loud, clean and indestructable (solid state) amp. This is the best affordable plexi tone I have found and I've tried a lot of 700 dollar amps in the quest. Plus it's easy to put effects between. A plexi clone? no, but way, WAY better cranked plexi tone than the Univalve. No noise because high power is clean power, the powerful amp is barely even trying. The Univalve is sweating it's ass off thus noisy. The Sansamp will provide better articulation and rich harmonic tone, loud or at TRUE, whisper quiet bedroom levels. Just try it, SAVE YOUR CASH, you'll see.

Did not have any problems.

I will never buy another THD amp. I tried it, it's nothing special for the price.

single-ended EL34 amp with built in attenuator

I hear lots of people saying that the Univalve sounds like an old Marhall plexi. Crap. These people did not own a plexi....the Univalve sounds nothing like a marhall. A Marshall will give you an outstanding overdrive as soon as you start cracking up the master volume (a different thing than having lots of distortion in the preamp....the one I am talking about is power amp distortion,which is what a plexi is all about).
The Univalve sounded sterile and too clean to me ,with it's master volume fully up.
It has none of the dynamics of a plexi.
The people that say that this amp will 'reveal' your sloppy playing (if you play sloppy) probably did not own a good tube amp before,and were too busy with their Boss Metal Master pedal crap.

Something else that I did not like about the Univalve: when it's cranked up and the attenuator is engaged.the sound was sort of coming and going....sounded unstable to me.
Overall,the Univalve sounds a little too cold for my taste. There are other good amps around. I will get a cheap pignose g40-v and will pay a tech to have it converted to EL34 valves instead of 6l6.
As this amp is based on an old Bassman,(old Marshalls were based on that too,they say) it should be interesting.

The Pignose costs a lot less than the Univalve. I am getting it as soon as I can

seems well built,but then again,at the price it should be.

as I said,it is too clinical in the power amp distortion area,for me,too cold

You can use virtually any tube you know off and adjust a degree of gain treble, bass and attack as you please ...

It depends on your valves: 10 if they are outstanding, or 6 if they are bad or old or 1 if they are dead.

WARNING: THIS IS NOT AN AMP FOR BEGINNERS or sloppy players as it is like a superb hi-fi systema nd does not pardon sloppy playing or less than perfect gear.

Some people rated it poorly as they have bad guitars or bad cables or (very critical) used cheapo tubes or (almost as bad) low-rate speakers.

This amp revals THE Truth about your gear, sound and playing so make sure you have everything on par.

Sloppy players and beginners stay out - or buy Line 6 or Roland gear.

3 years no problem

Great people - great community.

I use it mostly as my tone pre-shaping unit and plug it into one of my numerous other amps. Still, Univalve is THE best and most versatile.

If you have $850 and you are a SERIOUS about your SOUND and if you have some GREAT guitars and CAN play well - then simply - buy one !

I purchased my UniValve new in 2006.

Cool features: Line out: use it in the "Power Amp In" of a Fender Blues Deluxe. Increases the volume and accesses the Fender's reverb. I've also used this feature direcly into my 1964 Bandmaster head: very sweet sounds!!! Attenuator: seems to compress the signal a bit and drops out some of the highs, this is actually a good thing and I often use it on it's highest setting (e.g. highest volume) just to tweak the tone.

Bummers: No channel switching: I like to roll the volume back on my guitar to get the clean sound, but the hi-gain input just doesn't clean up as much as I would like. Being able to switch between the two would be great. However, with a 6l6GC tube there is more clean headroom.

No reverb: I have an analog spring reverb unit, but the Univalve's hi-gain input blows the sound up so much that it sounds like I'm playing in the Grand Canyon, and yes, I did turn the reverb all the way down. It's either off or Canyon city. However, it works beautifully for the low gain channel. Shame on me for not dragging the reverb unit into the store to check it out. Is this the deal breaker? No way!!!

I'm using a 2002 Gibson Special Faded Les Paul with Humbuckers played through a custom made 2X12 cabinet with Celestion G12L 35 watt speakers. I play mostly blues influenced rock. I was looking for the Allman Brother's sound. It took me about a week of noodling to find it...well actually what I have is a lot nicer in my humble opinion. It's smooth and creamy, lots of sustain, a very musical sound: no harsh ear piercing sounds. I set the amp volume at about 10:00 (1/3 volume) and the guitar between 7 and 10. The high is set very low (between 8:00 and 9:00) and the low is mid-way up. When I set everything at 12:00 (that would be 5 on normal amps) it was just way to bright and harsh sounding. The "Hi" nob is very sensitive between 0 and 3 and less so between 5 and 10.

This amp gets some amazing clean tones as well. However, with the EL34 stock tube a good clean Jazz sound is tough to get at stage volume. In a crowded club the vocal noise will be louder. With the volume all the way up, the amp distorts slightly bassed on how aggressive one plays. This sound is amazing, and wonderful for playing blues.

The reverb thing is hardly noticable until you stop playing or play staccato single note riffs. Pulled a blind test with the guys in the band. None of them picked up on the lack of reverb and were stunned when I clued them in. Don't really know why this is the case, but I like the sound. My Bandmaster has a similar effect but a more elastic / spongy feel.

The easiest sounds to dial up are the 70's-80's metal tones. AC/DC, Zepplin, The Darkness. Right out of the box my wife's jaw dropped and she said, "Oh, my God, that sounds exactly like AC/DC." Very fun to play, and if you've been trying to get this sound with any amp that doesn't have EL34s, then you will be stoked.

Warning: use your ear protection with this amp, don't be fooled by the wattage. Even on the 5 watt setting this amp gets very loud through the high gain input. If you play metal with a drummer that likes to play hard, this amp will not cut the mustard. On the other hand, every time I turn my Blues Deluxe up enough to get that nice power tube distortion going, the club owners run over pissing and moaning that the bartenders can't hear the drink orders: not so with the UniValve!!!!!

Overall I am delighted. I am planning on purchasing a KT-66 tube, but beyond that I'm not sure I would want many more sounds than what I already have. When David Geffen comes crawling back and begs us to accept his offer, I will buy a Flexi-50...and a BiValve...and a....

I've owned the amp for a few months...so far so good. It's built like a tank.

Haven't had any contact and haven't needed any.

I've been playing for... let's see 37 minus 10, ouch 27 years, what a cruel question to ask!!
I also own a late 1980s PRS Custom 24 and a Mexican Strat, however, I play the Les Paul most of the time. The best thing about this amp is that it get's the most amazing sounds at volume levels that are more reasonable. I practice in the basement of our house at night on the 5 watt setting and the kids on the second floor never wake up. Mom can watch the inane reality TV shows and chat on the phone during the commercials. Everyone is happy. This is not the case with my other amps. Fortunately, I play with some very tallented musicians who are all well schooled in the Jazz and Blues genres. Listening to each other is highly valued. As a result, I really do have enough volume. We played one gig in a medium sized theater. I ran the THD through the Blues Deluxe for a little extra stage volume, but the mic was in front of the 2X12. I could hear myself through the monitors no problem...kudos to the sound guys. It doesn't always work out that way. Finally, I tried out some very expensive "boutique" amps prior to this purchase. Bang for the buck this amp is untouchable!!

THD Univalve, manufacturing year unknown, but the serial number is #1336. Rock/Roll inputs, volume, treble, bass, attitude standby, Hi/Lo voltage selector, noise reduction, and power attenuator controls are on the front face; line out, speaker out, speaker ohm switch, and fuses are on the back. Most notable feature is removing the heavy-steel cage and trading out tubes to your hearts content. Very hearty construction, but you won't throw your back out moving it around. 2 pre-amp tubes and 1 power tube controls your tone. I presently have an unmarked 12ax7, an old Mullard 12au7, and vintage RCA 6L6 in the power slot. Rock, blues, country, jazz, and everything in between sounds wonderful through this head.

Given the ability to re-tube without biasing your amp as well as very touch sensitive controls, this amp is fantastic. Ideal for direct recording and live use, but not necessarily a road warrior amp.

I play a stock '04 Fender American Deluxe Strat, an '89 Les Paul Custom updated with Duncan 'buckers, and a Gretsch Electromatic Hollowbody with DeArmond 2000k single coils. All of them have subtle nuances that the THD embraces and amplifies. No more "everything sounding the same" when I play!! So far, I've been very pleased dialing in clean tones with the Roll as well as plugging into the Rock input and cranking the attitude knob. While you can get very loud with this amp, the controls allow you to use the tone and volumbe knobs on your guitar (remember those?) to achieve a smooth, compact tone that is very enjoyable at bedroom volume. I am also completely in love with the built-in Hot Plate attenuator to play with overdriven tones without disturbing the peace. If you're into metal, you'll probably want to check out the Bivalve or Flexi to boost your wattage. Otherwise, if you can't find a tone you like with the Uni, nothing is going to make you happy.

My Uni was brought in from a local recording studio when they decided to downsize their inventory, but it was used to good effect while they had it. Based on the research I carried out before, everything THD puts into the amp is designed to be more durable than any other manufacturer; this covers the wiring, the body material, fuses, and the overall amp to ensure that it'll last. I haven't gigged with this, but you'd have to throw it from a moving car to even dent it. As long as you have tubes (Heheheheheh) and fuses in your toolbox, this amp should last you for years.

After I bought my Uni, I wanted to build my own 2x12 cabinet and thought about calling to ask if they recommended series over parallel wiring. Called THD, and while the tech guy wasn't immediately available, the guy I spoke with twice offered to call me back or have me e-mail him directly and he would pass it on. I managed to get the info I wanted, but if I needed THD support, I'm fairly confident they would back up whatever I needed. There is also a dedicated group of THD users who post at univalve.net that can guide you through everything THD-related. Worth checking out if you're thinking of buying one of these.

I've been playing for about 15 years now, and I think that this may be the only amplified head I will ever need again. My new addiction? Tubes! Seriously, I went from a hybrid combo and an all-tube Epiphone Valve Junior to a tube machine that makes me realize what I've been missing. Although my ears aren't as trained as they should be and my playing skills are a little lackluster, you can really appreciate the difference in dropping a 12au7 in the driver position. See? Three months ago, I would have had no clue what that meant.

I was looking for this amp for a long time, and never saw one around. By chance I wandered into a local store one day and saw it used for a good price. At first, I kept trying to talk myself out of it by telling myself it didn't have reverb, that I'd have to buy a cabinet, surely something better must be out there. After three weeks of mulling it over, I couldn't get the sounds out of my head. I even brought my own guitars with me to the store, and it was the best sound they had ever made. Suddenly, the doubts became strengths: build your own cabinet, choose your speakers and be in charge of your own sound. Reverb? Playing in a room generates it's own reverb, no? A great-sounding 15 watt, hand-built, all tube, American guitar amp head for a reasonable price? Why was I trying to talk myself out of that?!?

Like a British sound? Thrown in a EL84 and slap it on Hi voltage. Love your old Fender? Swap in a 6V6 and keep it on Lo. Want your own sound? Load up on some old tubes from eBay, send the kids to camp, put the dog in the yard and tell the misses that she really should treat herself to some new shoes and spend the day putting your own mark on your Univalve with your favorite guitar; I think you'll like it.

i tried it in my local shop, but bought used. i like it's simplicity on the front, and i also appreciate what it has on the back. i find it very versatile for what i like to do. mostly i keep it at about 2-5 o'clock and it crunches nicely on it's own, but absolutely comes alive with my pedal setup. i haven't owned many amps, and only 1 other all-tube but this is an extremely responsive amp. it responds to everything from the slightest knob adjustment on your guitar to any variation in technique. it's awesome, with some obvious limitations that are easy to get around if you need to.

i've got a stock 93 gibson sg std. i play fuzzy stoner rock type of sounds, and with my pedal rig it's amazing. on it's own it wouldn't cut it for everything i want to play, but that's what pedals are for. my cabinet clearly can't keep up with this thing sonically, so i'm working on getting the goods in that area as well. i have a 500watt stereo power amp to beef up the volume that will be a consideration when getting my new cabs, but even with my crappy 2x12 this thing with my rig has me in acid guitar bliss everytime i plug in. it can handle a huge variety of sounds, depending on your speakers. i go from high end painful screech to superbassy sludge mainly thanks to my main pedal, an EH Micro Synthesizer. This pedal is insane. I also use an EH deluxe memory man and for massive sustain and feedback possibilites i have a little t.c. electronic preamp pedal. this amp rocks.

it always works for me

no experience here, but from what i read it sounds good

I've played guitar for almost 20 years now. I'd get another one if i needed to, unless i decded to buy the bigger one. i love it.

Wow. Pretty simple amp. Only 15 watts :( Are you kidding me. This thing is LOUD. I can not immagine you running out of volume. The 3 tubes are self bias-ing. Great head room. The amp really cuts through. Sounds like a truck. Everything is clear....even with alot of gain.

Gibson Les Paul Custom '1975 and an ESP Vintage Plus with EMG's. This amp does not care. It makes whatever you have sound like it's supposed to.

Haven't had it long enough.

I love it. I bought it from Avatar speakers for $600 and also purchased a 112 cabinet with a Celestion Vintage 60 (Hellatone) speaker for a total of $812 delivered. Smokin' deal. Geat gear

This is 1-yea follow up review of this amp. The features have not changed, and I still love what it has.

I have purchased a veritable cornucopia of fine tubes, NOS GE's Sylvania, you name it, I know own them. I always run back to the stock GT6l6B. Although I do love many of the other tubes, the sound is VERY subjective. If you get one, you need to experiment with not only different power tubes but also the Input and the Driver tubes as they may a world of difference even with the same power tube. None the less, whatever tube I've run in it had it's bright spots with every guitar and on just about every setting. The only disappointment I had was a Telsa JJ6l6 (which I bought off ebay and it simply could be a bad tube). BUT...the sound....my god, clean and soft to dirty and wild. there is NOT ONE BAD AREA in this amp. I will say you may find the Hotplate to be a tad too compressive with bigger output tubes, 6550's and such. Solution, run 6k6 or 6v6's, turn the plate voltage to low, and don't run the hotplate...WOW!

I have not been abusive, but I have also not treated it like a baby. It's my work amp...I need to play it....I play it...I pack it...i play it..i pack it. It's NEVER failed. NOT ONCE! It's forgiving and doesn't complain. Good tubes on hand, I wouldn't worry a bit. I never take a second amp (Call me stupid-but i don't feel i need one).

Well as I predicted, THD customer support has been OUTSTANDING at answering EVERY one of my stupid questions. ED is like my long lost brother keeping me in line, helping me not make stupid mistakes with my Univalve and giving me extraordinary guidance and suggestions. AND GET THIS......My amp is not under warrenty since i bought it used, but I still get treated like I bought a 1000 of them! Good luck getting ahold of fender or marshall...Mesa Does return your calls and helpful, but not like THD. i get consise info from ED within hours of sending him an email. I'm Saving my money for the flexi 50 to add to my collection just so i have something else to bug ED about for another year! THANKS GUYS!

This is an awesome amp. I would not have it for my ONLY amp because sometimes you just need the AB push/pull thing or that old fender recto sound. BUT....it is MY MAIN AMP. MOST TIMES MY ONLY amp, and IF i was faced with getting rid of everything except ONE AMP, this would be the one i'd keep. I have friends who are marshall guys, but we agree that a band has to have diversity otherwise you just blend...they have not respected my choices in amps (mesa-legend-fender, etc), however EVERYONE LOVES MY UNIVALVE like I do.

I think every knows but simply a one channel class A tube amp. Rock (high gain) and Roll (low gain) input choices, volume, trebble, bass, attitude (gain), attenuater(hot plate), high/low voltage switch are your only controls. I use this in my home studio with a 2x12 cab loaded with Tone Tubby Alnico's. This amp at 15 watts is way more power than I need. I add effect at the board so no need for a effects loop. My only beef is with the very cheap tubes that were factory installed. Change these right away or at least pull them out and reinstall them as they can come loose in transit.

I use a American Fender Strat Plus with Fralin pickups, a Gibson Les Paul Class 5 with stock Burst Buckers, and a Heritage 555 with P90 type humber size pickups. This is where I could write for days. What sound do you want? This amp will cover them all if you put in the right combination of tubes. You will have to be very patient though because there is a lot of tweaking that will need to be done on both the amp and your guitar. This is a very bright amp so be prepared to turn the trebble way down. You may have to turn the volume down on your guitar as well, be patient.

When it comes to tubes do your homework. I went on line and found out what tubes were in the type of amps I wanted to sound like. Be patient you may not like the tube with one guitar but try all your instruments. I have found sounds I wasn't expecting and been very happy with.

Speakers are just as important part of your gear. Find ones that you like that can handle more than one tone. I tried my friends Univalve through my Marshall 4x12 1960A cab before I bought mine. Although it did drive the cabinet it sounded better when I switched it to two speakers. It became more punchy and the low end really came alive.

This is were I thought I had an issue but upon further review it was a bad tube and the fuse did its job. I bought this amp new a month ago and it comes with a 2 year warranty. With all the power tube changing that I do I might need to have that looked at in a few years. I don't take it anywhere so it will probable last for a good long time.

I have not dealt with them but a friend did and they did right by him.

I have been playing for over 20 years. I have been in bands done the gig thing. I have played Fender, Marshall, Boogie, preamp and rack gear, and now THD. All were good but you would have to sacrafice one tone for another or half you garage space. With the Univalve you don't have to. Just switch a tube and you have a completely different tone. I would buy another one if it were lost, stolen or god forbid broke down. This is just the most fun amp I have ever owned. i hate to sound like an old fart but you might need to be older to appreciate this amp to its fullest. You have to be patient and the tone will come to you.

Nothing new to say here. It's just about everything you might need in a high-quality, single channel amp. The controls are all very powerful/useful, the amp is very sensitive/multi-dimensional, and the Rock & Roll inputs provide a two very different tones to work with. The built-in Hot Plate is very useful if you need to control volume-to-gain setting, and having it built right in to the amp head is very convenient and portable. No reverb, but I use a pedal for that.

'89 Strat Plus Deluxe w/Van Zandt Blues, mid-'90s Epiphone Casino, mid-'90s Epiphone Les Paul Custom with SD JB/Jazz >> TU-2 >> Barber Direct Drive >> MT-2 Metal Zone >> Xotic AC Booster >> Xotic RC Booster >> Yamaha MagicStomp >> Univalve >> Avatar G212H. Mostly rock music -- all eras. To me, the most remarkable thing about the Univalve is that it must be one of very best high-quality tube amp values on the market. Even if you aren't shooting for "bedroom-level" tube tones or needing wide versatility in a studio setting, this thing is just a great single channel tube amp for playing live. I play through the Roll input with JJ 12AX7s and a JJ EL-34L, set the amp for a basically clean tone with a little hair on it, and use pedals from there. With the possible exception of extremely loud/extremely clean (given 15 watts and the inherent headroom limitations), you can dial in a wide range of base tone/volume combinations. I would think the Univalve would also be an ideal "dirty/crunchy" amp in a two-amp A/B approach as well. Either way, I haven't seen anything else that delivers this kind of quality and versatility for under $700.

So far, so good. I've had mine for four months and used it fairly extensively. Seems very well made.

No experience here.

I've been playing for 18 years. The Univalve is a stellar amp, and I would definitely buy one again.

My Uniivalve was made around 2003 in Seattle. It's a single-channel Class A tube amp with one output tube slot and two for preamp tubes.

The Univalve doesn't have four channels, on-board effects or many other bells and whistles. Yet it has a feature that trumps all that: The ability to take a wide variety of pre-amp tubes, plus just about any octal output tube you can find. You can also use nine-pin types likle the EL84 with an adaptor.

Some other great features are a built-in attenuator, a very effective noise reduction circuit, a dummy load, two input for high and low gain, a voltage selector switch and a very effective line-out with adjustable level.

The only feature that would be great is some sort of way to switch on the fly between the high and low gain inputs to have psuedo clean-to-dirty switch. Right now, I just roll off on the guitar's volume knob.

I use Duncan-loaded Charvels (old Japanese models) for my band, which plays originals that are like The Refreshments meets the Scorpions. Since I do most of the lead work, I aim for a great high-gain tone. Using a 6l6GC output, a Telefunken ECC83 and a GE 5751, I get a distortion out of this thing you wouldn't believe. Nice low-end thump with beautiful sustain for the leads. An Ibanez TubeScreamer fattens it up a touch.

Whoever thinks the Uni can't do metal just hasn't figured out what tubes to use. This is certainly not a Bogner or an Engl, but it does a nice early Metallica sound if you have the right tubes, guitar and pickups.

The longer the gig, the better the Uni sounds, and it loves being dimed.

Between songs, I hear no hiss or other extraneous noise out of this amp. Even in venues that often create a lot of interference, it stays quiet.

After raving about the distortion, I plugged some 6189 low-gain tubes into the Univalve and turned it into a blues player's dream...very clean with just a touch of breakup if I attack the strings hard.

The attenuator is decent, but the Uni sounds better without attenuation. This amp reacts very strongly to different tubes, so take your time to experiment.

I am running this through an old Crate cabinet loaded with Carvin's version of a Celestion V30.

I've only had it about two months. After two practices, the output transformer died. THD replaced it and said it came from a batch that had a less reliable transformer. Since then, it's been running like a Swiss watch. Also, it had been sitting at a guitar shop for a few years, so I don't know how many people who don't know how to properly operate a tube amp may have handled it.

I won't gig with ANYTHING without a backup...guitar, strings, tubes, picks, etc. If I'm getting paid to play, I am going to do anything possible to finish the gig no matter how confident I feel in the gear.

I'm leaving this category as "no opinion" because I haven't had it very long, and it really seems my problem was kind of an abberation. If you like, I'll update in six months or so.

Every company is occassionally going to have a product that fails. I hope they all take care of it as well as THD did. They are pleasant, prompt and thorough. Not only did the replace my transformer in the incident mentioned above, but they upgraded some wiring to their current specs. And they didn't once act like my constant questions were a pain in the a**.

I have been playing for 16 years. My current band has been together just short of two years. During that time, I've gigged and practiced with a Marshall Jubilee, Laney AOR100, TubeWorks RT-2100 and a Line6 Spider II (borrowed!). The Univalve has given me by far the best tone of the bunch. The fact that I can drive it at near maximum output and get that great output distortion does it for me. And it's tiny, about the same footprint as a large laptop computer.

If someone stole it, I might scrape together a bit more money and go for the BiValve, which has double the wattage. That might help for some larger venues if they don't mic us...saves me from slaving it to my TubeWorks head. Plus I can still pull an output tube for smaller venues with no adverse effects (not true with all tube amps).

Seriously, this is a terrific product from a great company. They also have a great user forum (www.univalve.net) where people who own them exchange ideas and advice. Plus you'll have a tool to shape your own tone. And it's not even that expensive at street price ($845) and good shoppers can find an even better deal now and then.

The THD Univalve is an odd creature when it comes to features, for it manages to have both few and many all at once. At heart it is an 18 watt all valve boutique amp, designed for studio/ small venue use.

While the Univalve is a single channel amp, it offers both a high and low power input, labelled "rock" and "roll" respectively. The High power input offers everything from a raspy brit gain to a smooth hard rock distortion. The low power input has a beautiful clean tone to a crisp, bright crunch.

The tonal options of the amp appear somewhat limited, having a Volume, Treble, Bass and Attitude control. Each control gives quite a small range of tonal variation (your not going to get a good 80's hair metal sound out of this one) but saying that, the sound that is there is well balanced, warm and probably the best all round tone I have come across. When I purchased this amp I compared it directly to both a Mesa/Boogie Rectoverb combo and a VHT combo (can?t recall the model on that one) and I would have to say that neither had a shadow of the depth and richness of tonality that the Univalve can offer.

It is also worth mentioning that never before have i played an amp that responds so much to playing dynamics. The diversity of sound and tone that can be achieved through your guitars tone controls and your playing here really is amazing.

The interesting part of the Univalve is the built in attenuator, THD's Hot Plate. When turned on this allows the volume to be raised, so pushing the valves, without the added decibels. In a home studio environment this is one of the most useful features that you can ever have, especially considering how well it works. It also has a noise reduction switch, which dose just what it should without sapping any of the amps tone

In summery this is a very "pure" boutique amp, designed with the home studio in mind. In this roll their really isn't anything that THD could have done to improve the amp. Saying that, do remember that it is an 18 watt head and relatively tonally restrictive. If you?re looking for sweet Jazz/Classic Rock/Blues tone for your home recordings then this amp should be a serious consideration. If, however, you intend to play Black Metal or live at anything more than a house party then the Univalve is probably a little too "pure" for what your looking for.

I'm using three guitars at the moment, a Fender Jazzmaster 62 Reissue (the Japanese One) with standard hardware, An Eppiphone Les Paul Standard and a B.C.Rich Warlock with BDSM humbuckers.

The Jazzmaster sounds great, with its single coils offering a great range of tonal options that all sound just as they should. Surprisingly it also holds its own with the heavier sounds, offering a great classic rock tone (think Zed Zeppelin's Black Dog or Rock and Roll). The humbuckers of the Les Paul offer a warmer fatter tone, that sounds great clean, but gets a little murky when on a higher gain setting (but this is somewhat the nature of this axe, which is soon to have EMG's installed). The Warlock also offers great clean tones and a rich think gain great for old Black Sabbath and other pre NWBHM metal.

The noise produced is minimal, and the added noise reduction function eliminates even the rudimentary single coil hum.

As previously mentioned the sounds are great for all non Thrash/ Black/ New metal styles. I play a mixture of music including the Red Hot Chilli Peppers, Led Zeppelin, Black Sabbath, BB King and the Smashing pumpkins. The Univalve is great for the entire above, bar possibly some of the heavier elements of Sabbath, as it can lack a little bottom end at the lower volumes. I also play a little Metallica and Iron maiden, both of which I use my Yamaha DG1000 for, as the Univalve really doesn?t do that kind of high gain.

The clean channel can be played at max volume without any break-up, however the attitude control can give it a crunchy edge if that is desired.

The distortion is warm and sweet, not heavy, this head is great at singing sweet warm gain, but doesn?t really do the brutal metal thing.

I have never had a problem in the three months that i've owned the Univalve, otherwise theres not much that i can say here

All of the Warranty side is done at my local dealer, so i havnt had to deal with THD at all.

I have been playing for six years, and have owned several amps during that time. The THD is by far the best purchase that I have made to date. That?s not to say that this is an amp for everyone, but for those looking for tone over features, and wanting to record in a home studio environment I would strongly recommend trying one of these out.

If the amp was stolen I would snap another up without a thought. There really isn?t anything else out there that can directly compare to the sheer quality of tone and build that THD offer.

I love that it is a compact, pure valve amp that reminds me of why I wanted to play to begin with. There are all to many amps out there these days sacrificing quality for an abundance of often useless novelty features ( like the Line 6 Vetta) so its a blessing to see such a great little amp make a stand for quality tone and playing skill.

I would also say that the amp has helped further me as a musician, as I have learned to use my playing and guitar to create the sounds that i desire, rather than resorting to digital effects.

When I purchased I compared this to the Mesa/Boogie Rectoverb and a VHT 50 watt combo. While both are great amps in their own right, neither could match the amazing 3D sound that the Univalve can produce, and with the added bonus of the attenuator the Univalve won hands down.

In some ways it would be nice to have more power so that the Univalve could be used for more live work, however this would somewhat defeat the object of the amp (THD do make larger output versions, but in my opinion they lack the quality of tone that the Univalve has)

Hope this helps anyone who?s thinking about getting one of these. Also THD's website has plenty of audio tracks of their amps, of if you think this might be what you?re after I?d recommend a visit there.

All the features on this amp are for tone adjustment. And it has plenty. With a amp this bright, the tone adjustment makes a big difference. Treble, bass, volume, attitude, hi volt, low volt, rock or roll input, hot plate. I like to call the knobs, "tone removers", you have to remove the tone and brightness in certain places or its just to much. I think we all perfer to have "to much" not "to little." You find yourself working backwards on this one.

I didn't really care much for swapping tubes. I spent $200 bucks just to realize the one they had in it was the best. If I needed to change my sounds it's easyer to do it with effects and stick with the cleanest sounding tube (EL34) for me. Yet the tubes do change the sound and it's nice to have one more thing to adjust. You can never have too many options.

Well, Im a metal head, at home hobbiest looking for the best sounding all around amp. The best thing about this amp is, it has incredible clairity. Bright clean tone and punch! I match it with a carvin maple top and a 2X12 thd cab. It is has so much clairity my frigen eye balls vibrate. Dripping in tone is a good description simply because the amp is very very bright and clear. However, It puts out exactly what you put in, including effects. If you have cheap effects or a crappy guitars this amp = "trash in - trast out."

Use good equipment and fine guitars and this amp will bring just that.
It is like a true old school no BS amp. What you put in is exactly what you get out, including effects.

I have found this amp will play any type of music. Its like a perfect platform for whatever sound you want. I like metal and wanted clean clear professional hi gain distortion and or liquid bubbly cleans with delay and reverb so I had to add effects. no problemo.

I remember someone in hear said not to use pedels. Nothing could be further from the truth this thing was made for pedals. Just don't overdrive it or put distortion on top of distortion, usecommon sense.

I also like to bypass all effects for the natural clean tone of my carvin guitar. Ahhhhggghhh! The crispy bright tone! You must try this amp.

Perfect.

TBD

My long endured search for gear ends with this amp + I added a rocktron prophesy tube preamp with effects. It's like matching two of the finest instruments. Now I have "angus young" and and "dimebag" forever on tap with absoulte quiet clairity. No hiss, no pop, no fuzzs. I just need to add a prgrammable footswitch and Im done.