THD Bi-Valve Head

Save your money, sell your car, get a loan. Do anything you can to get one of these amps. They are special.

I am blown away with the sound of this amp. I have a couple of vintage Fender tube amps that sound good but doubt if I play them much anymore.

Just bought it. We will see.

Just bought it. We will see.

Buy one.

The previous reviews set forth accurately the cool features of this amp. I received my first Bi-Valve three weeks ago and liked it so much I had Musicians Friend ship me a second one. A second channel would be nice, but one can't have everything in a Class "A" amp. I like blues and hard rock which this amp can more than deliver.This amp is very quiet with good cables. Because of the mix and match possibilities she gets a 10.

The Bi-Valve is a tone monster and can be used for almost any style of music. Could probably be used for metal with the right trash in front of the pre-amp. I decided to get the second amp to use as a channel two. I'm using a Keeley/Framptone amp switcher which works like a dream. The Framptone is quiet and does not color the sound. My first amp is loaded with Groove tube GE 6L6's while the second has Groove Tube EL34M's. Im getting the best that each tube has to offer. Im running these amps through a Mesa Road King 2x12. I get an airy and open tone (6L6s) with the "open back" side, and a tight and responsive tone(EL34's) on the "closed back" side. The attenuator allows for some great power tube distortion. The choice of inputs (more/less), power level( hi/low),attitude control,tubes (preamp/power),and attenuator settings open up a new world of tinkering for tone. My Gibsons sound great as do my Fenders. The amp is quit powerful and has no trouble pushing a four ohm Road King 4x12 cabinet. With the full power settings the B/V can get quite loud.

Just got-em so I have no real basis to evaluate. Seem to be built like the proverbial brick !!!!house. I would run-em without a back-up.

My first amp came on a Friday and was missing the power cord. I immediately called THD and advised of the situation and they mailed me a cable the following Monday. They only asked me for the amp's serial #. I Received the cord on Wednesday. The warranty is two year, transferable. I have E-Mailed questions on three occasions and received responses from Ed DeGenaro w/i two or three hours.

Been playing on and off for fifteen years. I own some Boogie gear
(Road King, Stiletto, Lone Star Special) and a Marshall JCM 900.Have various Gibson and Fender guitars. The Bi-Valve has its special place in the collection and cannot be duplicated by my other amps except, possibly, in some areas, the L.S.Special. This amp is too cool. On its face the price may seem high but you wont mind once you try it. If I got ripped off I would damn sure replace the Bi-Valve.

Rock-On!!

THD BiValve 30 Watt Head Single channel amp, hi and lo inputs with a significant difference in volume between them, bass, mid and high frequency eq controls and attitude control to adjust the tightness of the sound being fed to your speaker cab.

The amp also has a high and low voltage plate switch that works great to allow for different tones from the same tube combinations and a built-in hot plate attenuator, which, for me, is a fantastic feature, since it allows me to use the amp for low volume/high tone practice at home. FInally, there is a light bulb feature for noise reduction, which also works really well.

But the one thing that sets this amp way apart from the rest is the fact that it's 100% self biased and allows you to use any power/preamp tube combination under the sun! All these features provide you with a real tone lab and, most importantly, a W I D E road to finally find your tone! Two big thumbs up on features!!!

All in all this amp is built like a tank and constructed very well. I bought mine used on ebay and had it shipped from the US to Italy, where it got "lost" in customs for a couple of weeks - no problems whatsoever - the amp sounded great from the day I got it and it just gets better and better everytime I play it.

In just two words - SIMPLY AMAZING!!! There is apparently no limitation to the variations of sounds you can get out of this amp, except for metal, which requires you to plug into a boost or distortion pedal in front of it. Aside from this, this amp can deliver just about any sound you want.

This amp is extremely touch sensitive. Any change in attack is noticed immediately. It is also very transparent and, no matter how hard you drive the tubes, your guitar's and playing style come through it clearly.

SInce it's a single channel amp, one of the things I had to get used to was to control the tones from my guitar's volume knob, but after about a week of playing, I cannot imagine going back to channel switching.

The amp is extremely quiet, even at full volume on high input, thanks to the light bulb. Without it there is a little hum, as well as when using single coil pick-ups, even if they're hum-cancelling.

I play mostly blues and classic rock, but go to hard rock and some modern metal once in a while. For the latter tones, I'm currently using a Fulltone Fat Boost in combination with the boost feature on the Radial Loopbone and it works really well for me. The tubes are JJKT77 and JJ EL84 in the power section and JJ ECC803S and JJ ECC83S in the preamp section. I use the low voltage switch and it works just fine for me.

Built like a tank. No problems whatsoever!

Ed De Genaro is the greatest guy when it comes to your questions. I've e-mailed him several times to ask questions before I bought the amp (when I was reviewing it here) and after to ask questions about the amp itself and other products to go with it. He always answers the e-mails, usually from one day to the next and he's a great guy to talk to.

Together with Tom Anderson (Roy and Co.), other companies should take note of how customer service should be done!

Fantastic value! It isn't cheap by any means, but it's worth every penny and all the wait to get it. If it was stolen, I'd get another one.

One word of caution and, actually, confirmation of a few of the reviews I've read here: be prepared to spend some bucks on tubes, as you will go nuts experimenting with them. I'm still buying tubes and I'm sure I will be for a while still...but it's a great and rewarding experience, since everytime you get a new type/brand and put it in, it's like getting a new amp or for sure a new variation.

Have fun!

I'm sure you've read in the other reviews the greatest feature this amp hold. The ability to put in almost any tube combination you want without having to rebias the amp. Just plug and play.

On top of this the amp has a very cool and modern look about it.

It's a 30 watt one channel monster. Many people might be put off by the fact that it doesn't have the ability to switch between two channels. I would suggest getting a pedal or if you are crazy like me, get another head and ABY them. Currently I am running the THD through a Hartke 410 cab with a VHT 212 cab. I have a Fender Prosonic head that I am running through an old Hartke 412 cab with celestions. With the ABY I have the ability to switch between the amps or play both of them at the same time. This on top of the tube switching capabilities allows me to have a multitude of sonic abilities. Let me tell you, when I run both together, oh my god, pure molten lava comes out.

Another cool thing about this amp is the hot plate power attenuator. This allows you to squash the signal and get the right amount of saturation on your distortion at whatever volume you play at. Many people say it affects the sound in a bad way, but I don't think so. To me it sounds great.

Even though this thing has only one channel, you can switch the tubes, cabs, and guitars to get ANY sound you want if you only take the time to experiment. This baby is a sound scientist's dream amp. Currently I have tried only one tube combination: 2 Groove Tube 6l6 and 2 Groove Tube 12ax7 tubes. It sounds fantastic. The distortion sounds great and is not too saturated allowing all of the notes to ring through. This amp will surely show you the flaws in your playing as you cannot hide behind saturation.

This baby will get plenty loud. Without using the hot plate I cannot get it over about 3 when I am practicing with the band, so I find it difficult to get a lot of distortion without using the hot plate, although I'm sure if I did some tube experimentation I could.

The guitars I use include the following:

1970s Gibson double customized Les Paul Custom with three pickups
1990s Gibson Nighthawk Special with three pickups
1970s Gibson Marauder
1994 Epiphone Les Paul standard (soon to be customized)
Early 90s Wayne's World Ltd. Edition Squier Stratocaster
2004 Dean Exotica Accoustic

All of these guitars sound great through this amp.

This thing is like a tank and very heavy. I have yet to gig out with it so I can't say how reliable it will be when I start. So far I have had no problems.

This is where THD really shines. If I could give them a 20 in this department I would. I emailed Ed Deganero multiple times about the amp a I received a response every time within a couple of hours. I needed some cleaning tips and the manual(which he promptly emailed). One time he even called me at my contact number no more than 5 minutes after I sent an email so he could talk to me directly. I asked him some questions on speaker impedance and how it relates to the amp. Technically I wouldn't think it is his responsibility to explain this to me, but he did so in such an efficient and personable manner that I nearly couldn't believe it was actually happening. I have NEVER received customer support of this level ANYWHERE! These guys are great and will do anything in their ability to make sure you are fully satisfied with their amp...and trust me, you will be.

I have been playing seriously now for about a year or two and I can't say enough about this amp. If it was ever stolen I would certainly buy another one without any amount of hesitation. To anyone who is looking to get a $2500 head, do yourself a favor and pick up one of these instead. You will be glad you did.

The only thing about this amp is the fact that it's hard to find in a music store unless you live in California. I took the word of these reviews and bought this amp without ever having listened to it in person. There are some sound samples on www.thdelectronics.com that are good, but depending on your speakers it is nothing like hearing this baby in person. I am so happy I took the chance, it was well worth it.

2004 - Versitile Yes with able to change tubes without re-bias, single channel class A, the amp is extremely loud for 30watts. Excellent for rock. Takes to good foot pedals with the best. Features are covered in other reviews.

Guitars - PRS McCarty; Swamp and fender american strat. The amp has the cut-through in a multi-guitar band that you need. It does require a cabinet loaded with good speakers. (vin30 and g12h30) If not it will sound thin and harsh. I use a boss noise supp., so noise is never a problem. The amp does not have a great deal of gain, even at full throtle. I use a H & G Tube Factor for more gain. However it will kick your ear-in-the-butt at max vol. Think of a Marshall Plexi with class A attack. Your chops better be up to power.

I've owned the amp for 2 years with no problem. No backup. However I own or have owned over 30 amps in my 20+ years of playing this one rates with the best.(TopHat,VoxHW,Hughes ect...)
uilt like an anvil.

Andy was great to deal with. I highly recommend if this is your kind of Tone...

20+ years of R & R, I don't think you could go wrong with the THD-Bivalve. Solid in all areas.

Got to start by saying univalve.net is a fantastic site for THD users, don't talk to THD before you visit this dedicated web site for THD heads. A great bunch of players and answers to every imaginable question THD and more...

Features, everything I need.... took some getting used to the unique THD features such as Hotplate, Attitude & unique EQ response. But very versatile and sounds that are everythign they've been described as.

I am posting this review after 16 months of ownership... so I think I am across what it can do now... : )

Using '92 Les Paul & Custom Tele with SD STK1 & Lil'59,
Good for country & western music.. lol.. Rock, roll, not a high gain monster... pure pedigree with attitude...

It's a brick... all quality here people, streets ahead of the pack on this aspect.

THD are second to none in service... irrespective of what a stray comment on this site may say. Go to univalve.net to get an idea of what I am talking about.

Yes I have had an email that they did not answer on day 1, but they are busy, busy. I rang 'em and persisted and they went out of their way to help me.

I ordered a 240v conversion kit - unreal support.... direct from Ed DeGenaro (serious pro by all measures - helping lil' ol' me get sorted - what a guy!). Too easy!

Killer...

I am not sure of the year, this is a single channel tube amp. I love it. It has everything and more than I need in an amp to play in a band situation. It isn't a fancy amp other than how versatile 1 channel is. The tweakability is where it is at.

Thinking that most amps with 2 channels lose something on the way, I am giving this amp a 10.

I am playing a Peavey Generation Series 1 guitar with a duncan distortion in the bridge and a classic strat pickup in the rear. I run this through a wah, and I run a DOD bifet preamp in the loop for solo boosts. The amp is quiet so far, I swapped one of the 12 ax7 out for an at 7. It sounds less preampy. I am runnin this through a Z best cabinet which more than beats the competition.

The amp gets a nice distortion that can be cleaned up nicely with the tweak of a volume knob (on your guitar). This is of course if you are like me and prefer a less preamp gainy tone.

Otherwise you can use whatever tubes float your boat. I am fairly new to this and haven't experimented too much, but my bet is that BRUTAL DISTORTION is available depending on your tube selections. Like 2 12 AX7 and some KT 88's!!. I think this amp can get most tones pretty close. EVEN brutal!! It has USABLE distortion not muddy. Keep in mind your speaker cab plays into this as well.

I have no opinion YET!!

I emailed Ed Degenero and he was nice and helpful.

I have been playing 25 years. If it were stolen or lost I would get another one. I love that this amp is completely your own beast. You can do with it whatever you want tube wise. This gives it major appeal. But not to be forgotten, this amp sounds great. It is hard to make it sound bad actually. The tonal controls are very usable and very sensitive. I have stopped looking for tone after finding this amp. This amp gives me so much satisfaction I cannot explain in this box!! Anyone spending $3000 on a boutique amp should be looking at buying 2 of these!! The distortion is so usable and musical sounding. Even at brutal distortion levels (which isn't my thing) this amp sounds very clear sounding with the right tubes.

As listed already, but basically:
30-Watt Class-A, Single Channel Amplifier head
Built in THD Hot Plate
Effects Loop, Line Out w/Level Control
Hi-V/Lo-V Voltage selection
2 Inputs More and Less (only 1 can be used at a time and you can't A/B them)
Best Feature: Change Pre- and Power-Amp tubes endlessly to hone in your sound.

This amp pretty much suits my needs perfectly. Most off the shelf amps have some good tones, but none of them really are "me." While,
I'm still experimenting with different tube combinations I'm getting much closer to the sound I want.

The only feature I wish this amp had would be the ability to A/B the Hi and Lo inputs, making it a quasi-channel switching amp.

Sound is very subjective, but this amp is getting me closer to the tone I am seeking. The ability to change the tubes to almost any type made is one of the best features and the primary reason I purchased this amp.

I play just about every style of music from Classical to Jazz and Country to Rock. This amp is very touch sensitive and dynamic. If you play sloppy through this amp, you'll get a sloppy sound, but play with some feel and good technique, and this amp will sing. If I have one beef with the amp, it would be when the Hotplate attenuation is active. If you crank the amp and play with some force, there is a noticeable, albeit brief, "sag" and dropoff in the sound. I've only experienced this with the HotPlate active, but I guess it wouldn't be an attenuator if it didn't attenuate the volume.

Playing through the More input will give you an edgy clean to a nice, smooth distortion. I'm not sure if you'll get metal sounds from this amp, but hard rock sounds are abundant. Again, depending on the tubes you use, you can get more or less distortion. The Less input is clean throughout the whole volume range, with maybe a slight edge at peak volume.

I use the THD 2x12 cabinet with this head and get some great low end with this amp. My guitars are a Van Halen Music Man, Fender Lite Ash Strat, PRS Rosewood McCarty, and a custom Tele with Seymour Duncan Phat Cats. All of these guitars sound great through the amp and each add their own character to the amp. One thing to note...my volume knobs on the guitars actually work! With a channel to switch to for leads, I've found this amp to be very dynamic in responding to volume settings on the guitar.

I'll give it a 10 because it's been rock solid, although I've only had it about 1.5 months.

I sent an email to THD regarding tube specs and performance with the amp, but never got a response. Not a huge issue, I was just looking for some extra resources on tubes.

I've been playing for 17 years and gone through my fair share of gear. This amp is one of my all-time favorites. I really feel like this amp allows my personality and style to show through. So far, I've only used EL-34's in the power section (I swapped the stock ones, which weren't as "alive" as the Groove Tubes), but will eventually try some other styles of tubes. Also, I put a 12AU7 in the Driver position and it really cleaned the preamp section up (I favor Power amp overdrive more than Preamp distortion).

I looked at the Mesa Boogie Lone Star and Dual Rectifier, some Traynor amps, B-52, Vox, and Dr Z before choosing this amp. I think the allure of tube swapping really grabbed my attention as the other amps did not allow customization of the tones as much.

Really simple...No boost, no reverb... More and less inputs, high-cut switch, 2 speaker outs with selectable impedance switch, effects loops w/ effect out level control, bass, treble (no mid), volume, attitude (shapes the distortion character), high/low voltage switch, built in hot-plate attenuator, noise-cancelling circuit w/ a really cool red bulb reminiscent of old Fender amps...and the best part...complete tube swapping freedom without ever having to bias! I give it an 8 for versatility just because no mid, no channel select, no boost, no reverb, etc.

I've owned this amp for about 4 months and I've played Strats, teles, 'Pauls, an Ibanez semi-hollow, even my acoustic guitar. This amp sounds sweet no matter where it's set at and is perfect for just about everything you could think of. It doesn't do the Mesa thing though...But it does give you amazing tones. Lots of harmonics...My favorite settings so far are an EL34 and a Mesa 6L6 together and a 6550 and an EL34 together. The 6550 gives it a slightly darker sound that compliments my Tele AWESOME! I run the volume all the way up, the attitude about 2 o'clock, bass at 2 o'clock and treble at around 10 o'clock. It gives a sweet, complex, dark and rich sound.

Built like a tank, I've gigged with it quite a bit and it never gave me any trouble. I've heard you can even use this thing to test good and bad power tubes (I wouldn't recommend it...but it's possible)

Dave at Avatar is an amazing guy to do business with. He sells awesome products and backs up everything he puts out the door. I know he along with Ed and Andy at THD would rapidly take care of any situations should they arise. Ed promptly answered every question I had about this amp.

I've been playing guitar for about ten years now and I'm by no means a master, but I know good quality and good sound when I find it, and this is it. If you are a cheese-head who's idea of good tone is the volume and gain pushed past 11, this ain't your amp. But if you are looking for an amp that will let you find your sound, this is it. I played Vox AC30s, high end Marshalls, high end Fenders, Mesas, etc., and could not find the "sound" I had in my head, until I took a chance on the BiValve. I would replace it with 2 more if it were ever lost or stolen!

Serial #0665...not sure what year that equates to, but purchased new from Dave at Avatar Speakers in July 05. Check out http://avatarspeakers.com/ for some great prices on THD & Avatar Speaker combinations. Regarding features, this amp could not be simpler...single ended, class A, treble, bass, no boost, no reverb, not even a midrange eq. The beauty however is the engineering on the inside with the ability to mismatch power tubes...even run on a single power tube. The built in THD Hotplate is a plus when set at 12:00 or higher but tends to over-compress & choke the tone when set at quieter volumes. The full-power switch bypasses the Hotplate entirely for the best no-compromises tone. A Hi/Lo voltage switch lowers the voltage from 450-470 plate voltage to 300-320. Lower voltage produces warmer and more spongy character...and, maybe even more importantly, to use the great old 6v6, 6k6, etc tubes from yesteryear that can't tolerate high voltage of most amps. The "light bulb" feature reduces hum somewhat but I find that I rarely use it...at least not at reasonable volumes because it seems to take a little of the shimmer off the tone...but this could just be in my head. The "attitude" control operates like a subtle drive control, making the overall tone more aggressive. Two inputs "more" and "less", as the name implies offers the choise of a hotter vs lower gain input. I find myself using the "more" input exclusively and using the attitude control to put some "hair" on the tone. A dummy load allows you to unhook the speakers for direct recording, but you'll need a cab simulator or you'lll get some pretty funky tone. All things being equal, this design is a thing of beauty!

I'm primarily a single coil guy...my primary guitar is a Warmoth VW set up like a strat w/ a killer Rio Grande Muy Macho set (Stelly, Muy Grande, Muy Grande)and flame maple top & maple neck. The combination of the beefy Rios and the bright flame maple top & neck make for a very balanced tone and sounds incredibly "3D" thru this amp. Right now, I'm experimenting with a Boss VF-1 multi-effects in the EFX loop with great results, but even without the VF-1, and plugged straight into the "more" channel, the #2 & #4 positions it give off an almost "chorus-like" high-end chime...very satisfying.

I've not gigged with this amp yet, but I'm pretty OC about stuff breaking...I'd bring fuses, tubes and a Digitech modeling pedal to plug into the PA if all else fails. That said,it appears that Andy Marshall and his crew are also OC about building a bulletproof amp...I have no doubt that this amp will survive whatever I can dish out.

Ed DeGenaro at THD is a guitar player's guitar player and the nicest guy you'll ever email. THD's has a reputation as a company that spends the $ to make the very best over-engineered product out there and then stand by it religiously. It was the tie-breaker in my decision to buy this amp sight unseen, based soley on the MP3s and the Harmony Central reviews. They exemplify the saying, "...if you don't take care of the customer, somebody else will".

I've been playing 35 years blues/rock, roots, and stright up rock...and is influenced by guys like Jimmy Thackery, Bugs Henderson, Johnny Winter, David Grissom, Gary Moore, etc, and this, IMHO, is the perfect amp. I've no doubt that, with the right distortion pedal and a closed back cabinet, you could go for any modern tone. The bottom line is that I can not say enough about this amp, other than this is the most satisfying purchase I've made in 35 years...it's simply the best amp I've ever owned. I'll still pick up a stomp box here or there, but my search for basic tone is over.