THD Bi-Valve Head

Enough said. Great stand alone amp or using as a preamp for other amps. Basic and versatile. Not too complicated but you can make it work for a ton of different needs that come up. My favorite feature is the fact you can go from 30W to 15W by pulling an output tube. The hotplate is useful but I never use it b/c my ears hear a difference when it is on. Channel switching would be nice but I would not likely use it with my current setup.
My tech knows more about tubes and the specifics than I, so when we are in some city, he stops and somehow finds great hard to find tubes. So we have a nice collection. I give him the ability to change at will. So we do a lot experimenting and we actually keep getting more specialized and better results as we go along which makes it exciting for he and I. That is a feature in other amps that would be a pain in the ass, but with these amps you just pop the top off and have at it. So for me it is a ten.

I play in a semi-national band, touring 3-5 days a week. We play anywhere from 100 person clubs in NYC to larger theatre-sized venues in our markets. Our style from what I am told falls between Our Lady Peace/Counting Crows/Catherine Wheel. This is simply one of the best amps I own. I use this in conjunction with the univalve (as a preamp/dummy load) using a GCX switcher to place the univalve in and out of line. An Axess Electronics BS2 splits the Univalve feed into the Bivalve and a Vox AC30. It is running a Mesa 4x12 w/ Vintage 30's. The great thing about the Bivalve is the ability to roll the volume off of your guitar and get very complex crunch/clean overtones. I am playing on Les Pauls and SGs w/Fralin pickups and it really adds something special to the overdone Marshall/Mesa thing. I run this amp slightly distorted allowing me to have a clean sound when I play soft and a crunch when I attack harder.

The amp sounds are complex and broad. It can sound like whatever amp you have played on, trust me. I get a overdriven Vox Top Boost sound out of it. Could be the tubes and the way I use it, but when I run the Univalve through it, is straight power amp distorion. Cuts through the mix and has very defined frequencies. It makes me play better b/c there is no moosh to hide behind. It is a very articulate sounding amp. I have done the Marshall/Mesa/Fender thing for years, but wanted a new direction for my band and my sound in particular. Well I am glad I found the Univalve 3 years ago, b/c it pointed me to this amp. For real touring musicians it is great b/c when we play smaller club dates I switch to 15W and when we play our theatre dates I can just crank it.

Reacts great with any array of pedals. I have used the effects loop and it is good. I just prefer to run everything in line. I give it a 9 for the many useful sounds you can achieve with it at the turn of a knob. Very reactive tone knobs.

Here is the best part of the amp. Great company, great personal skills, and great designs. I have a backup to everything just in case. But with this and the univalve I bring extra tubes on the road and I really never have to worry about anything. I can not honestly say that about any amp I have ever played used. When we go out and are not coming to home base for another 3-4 months reliability is more important than anything. Yes I use a Vox AC30 too, but we have to bring two others AC30s to get us through one of those 3-4 month tours. That is a pain in the neck and was in our pocketbook.

Great! These guys are class acts. When you find a company like this you stick to their products. For me they are up there with the Robert Keeley's of the world.

Been playing for about 10 years. I have honestly had a lot of amps and gear (Marshall DSL-50, Marshall Master Head, Marshall Super Lead, Laney VC-50, Orange Combo, Fender Dual Showman, Fender Bassman Heads, Mesa Boogie Maverick, Mesa Tremoverb Head, Matchless DC-30 (stolen), Mesa Triaxis, Marshall JMP-1...etc) This is the one amp that I will always use on stage and in the studio. I will always have another flavor of amp with me to add to the sound, but this is a must for me. I am fortunately in a position to influence some people and I always point them towards this and the Univalve.

Its hard to rate this catagory. I play vintage-type amps exclusively. Compared to most vintage-type amps this thing is packed with features but for someone who's used to channel switching its not that flexable. Yet if thats your complaint I think your missing the point of amps like this. I wish it had a preamp circuit closer to the classic british design (normal and bright volumes, Bass, Mid, Treb) but it has its own thing and honestly I cant knock this amp in any way in the feature dept. Its crazy but I think more then anything else I love its size. Just my marshall heads alone take up so much space. Plexi's are huge. HiWatts are huge. If I set the THD cab Vertically (on its side) and set the BV on it I have a little mini stack like those old Sovtek Midget stacks. But this rig has huge tone. The tube flexability is obviously a big deal. Prepare to spend some $$$ on tubes if you dont have a collection. That can be fun though. Tweakage and trials. If you like that sort of thing.

Ill say more then anything else I like the features of this amp. A 10 in this catagory says versatile. In a modern sense I guess its not but to the vintage/boutique world it really is.

I like Les Pauls. I like PAF type pickups.

For people reading here trying to figure out what the sound is of the BV Ill say it sounds closest to early marshall sounds. Its hard to pinpoint it as one thing but it seems to really be in that early marshall heritage. Not Vox or fender as much as marshall. Youll find an accurate ACDC and Rush way before youll find Brian May or SRV. Not to say they cant be found but its easy to dial in those sounds right away, especially with the stock EL34's. Its like a Metal Panel Plexi with a little bit of Vox and Bassman thrown in. Its definitly got a high bite to it like a 70s plexi. An accentuated higher range that can seem shrill or can be on certain settings. Theres ways to defeat that and get real warm or even brown tones with this amp.

Vintage style amps like this just have such a unique and amazing tone. They chime. You can hear all kinds of overtones when you hit an open E. It makes all modern amps and distortion pedals and all that stuff sound and feel the same. The amp's unforgiving. If you have bad technique youll sound bad with this amp. On the other hand if you have good technique youll find this amp very rewarding.

Heres a few things I found with the tone. Im a huge marshall fan so I tried the hardest to nail those tones. Ive gotten very good Vox at times as well. Ive had a harder time getting fender but Ill admit I havent tried much at all. I also focus more in the crunch tones then clean tones.

One thing with old marshalls is that its very common, when trying to get a tight, high-gain tone, to dime the treble and mid and leave the bass at like 2 or 0. The tone controls of old amps seem to interact more with the tone of the amp. Modern amps eq's seem like stereo eq's. They only adjust the loudness of the frequencies. Setting the bass on 0 and the treble on 10 would make a modern amp sound like its inside a tin can. On old marshalls, and the BV, the tone controls seem to alter the frequency responce more. Their a bit more interactive. When the bass is up high the gain is very loose and tubby. When its low the gain is tight and chunky. I think with the BV if you want a cleaner or bluesier tone you can have the bass higher but for a little more gain and a tighter tone you want to dime the treble, or at least set it to 12o'clock or higher, and turn the bass off. It doesnt make the amp sound suddenly like it hass no bass. Or make the treble suddenly tear your head off. It just makes the overall bass responce tighter and thicker actually. Its very common with old amps to run the tone controls in that way. For a brown sound with this amp I think its a necesity. I can get a very warm and soft yet tight, EVH-like sound were you really get a nice thick "chunk" when playing those mutes low strings.

The Attitude is a weird control. I like to keep it at 10 to get the most "plexi" out of it. It also tightens up the gain and makes the amp seem to have more gain when its up. I usually only turn it down when Im going for a cleaner tone.

One thing about getting more gain with the BV. Using a 12ax7 in the driver only makes life harder. With 2 12ax7's in this amp and the volume dimed its a very loose, out of control gain. Fuzzy and feedbacky. I like to use a 6189 (12DW7) in the driver to tame that gain and I can get a tighter, higher, smoother and warmer gain as a result. The 6189 also tames the harsh top inherent in this amp. a 6189 may be a lower gain tube but its more useable gain. So I can actually turn the volume up to 10 and know the gain will be smoother, chunkier and tight.

With these few things I can get a really nice, ballsy crunch. I can also get a great brown sound. Obviously to get more of a classic plexi crunch sound it should be on HiV and to approximate the EVH sound it should be LoV. Or better yet. Leave it on high and use an actual variac.

I want to stress another thing Ive learned. Moreso with this amp then with others Ive played, the speakers make a

All I can say is they answer emails in 1 to 2 days.

This is a review I have been meaning to contribute for a while. I've had this BiValve for almost a year now, but I wanted to wait until I recorded with it and had planty of time to test it out to give a fair honest review. My bivalve is 2002, #141. All the features have been previously listed but I will say that the controls are very simple, intuitive and musical. Every knob and switch (of which there are not many) is very useful, and the only thing I wish it had is a midrange control. Although I love the midrange content in it's natural tone, I would like to be able to dial in more midrangey crunch for some things. overall, though I'd say the amp is very well designed and versatile. Although I do also wish (really wish) it had the ability to use an ABY box to switch between low and high gain inputs. This would make a live situation much easier as the amp only has one tone instantly accessible. and I can't exactly afford to have two of them.

This amp has some incredible sounds and is extremely versatile. Much more than I thought when I bought it. When reading the glowing review, I doubted this amp could do all that previous reviews said it could, but upon hearing it I was sold. The true test is that when I bought it, my musical style was different, and having changed styles, the amp had adapted itself perfectly to my new playing.
OKay, well if anyone cares, my rig consists of a stock lefty G&L asat special semi-hollow w/ soapbar style pickups, or a heavily modified lefty Gibson SG special w/ seymour duncan pickups (which btw will soon be changed to joe bardens). My pedalboard is simple, I run either guitar into a VHT valvulator line driver (a buffer that converts your signal to low inpedance to save your signal from tone suck caused by long cables and pedals), a snarling dogs blues bawls wah, a fulltone fat boost, and a boss tuner and noise reduction pedal. I run the bivalve into a THD 2x12 cabinet which also sounds great.
As I mentioned earlier when I bought this amp I played a different style of music. I played Heavy Rock along the lines of Tool and Soundgarden. The belavle sounded great for this and thats initially why I bought it, for the massive overdrive sounds. I put of pair of 5881's in it along with some high gain 12az7's and I could get big massive grind. Now, my style has changed to a more Rock/Pop/Blues/Spacey kind of thing that way more vintage sounding. I can use an EL34/6L6 combination for clean dirty, or a pair of EL34's for crunch and it has great clarity and punch. With different combinations of power tubes (EL34, 5881, 6L6gc, KT66) and a few different variations of 12ax7 and 12at7 preamp tubes I can dial in everything from really clean, to egde of dirt on the low gain input and blues rock to ballsy crunch to singing lead to massive distrortion on the high gain input. I really am quite impress with the versatiity. I wouldnt really call this amp truly high gain, but thats good for me because i don't want rectifier tone. it also doens't have as much clean headroom as a fender but I have a fender amp for that.
This amp records really well and cuts through the mix great. it's versatility is welcome in the studio and it isn't noisy at all. I rarely use the noise reduction because the light bulb tends to burn out fairly quickly and it has a slightly negative effect on the tone. Oh, and in case you think 30 watts isn't loud enough, try running this thing without the attenuator on, it'll rip your head off! More than loud enough to keep up with a band practice. I'm sure you could use it live and it would be more thanloud enough as well, but any club you play at with a decent seating size will mic the amp anyways and tell you to turn down. I think 30 watts is plenty and more than that is just silly unless you need crazy clean headroom.
The hot plate attenuator does a great job of reducing the volume without affecting the tone, but be forewarned: don't expect to be able to run this amp at bedroom volumes and have massive sounding tone. The reason for this is the speakers, not the amp. When a speaker (especially an 80 watt celestion like what comes in the thd cab) is not given a lot of power, it won't sound good. All the distortion in the world won't sound huge without good speaker break up. For this reason I almost prefer to run the amp with the attenuator off at low volumes. It has way more harmonic content that way and a bit more treble as well. So, in my opinion, the attenuator is great, but you can't create cranked amp unless you crank an amp.
When I play this amp live, I am probably going to run the amp at full power on the high gain input with the volume at abot 1/4 (which is still plenty lound and decently distorted) and use a good tube distortion pedal (like an SIB varidrive) to get my overdrive sounds at a reasonable volume. Although the distortion on the amp is incredible, I need to versatility of switching between clean/dirty

Okay, check this out. This amp is extremely well built and is very dependable. But after having mine for about 8 months, it just uyp and died one day. Just suddently in the middle of my playing, the sound just cut out and was reduced to a mild fizle. I thought it might be a tube or a fuse but it wasn't. I called THD and Ed Gegenero (very nice guy) told me he thought it was a cold solder joint that had come loose and I should send it in for servicing. I was nervous about this because I needed to record with it in less than a month and I've heard how long some companies take to service thier equipment. But I sent it in and had it back in well less than 2 weeks. Ed kept in contact with me via phone and was very helpful. They even sent it back to me with a brand new set of power amp tubes at no charge! The amp has worked perfectly since. one time I though it had died again (this problem turned out to be a George L's cable that I had improperly connected and subsequently came loose cutting in and out) and I called and spoke to Ed again. He said to check everything including the tubes and if the amp had a true problem that I could send it back and he would send me a brand new one. SO it's clear that they really stand behind their product. I would gig this amp without a backup, although not without some spare tubes and fuses just in case. Although I've never personally blown a fuse, some other reviewers indicate this does happen.

As mentioned before THD is great to deal with. They are super helpful and nice and they really take time to tlak to you and answer all your questions. All of my many stupid e-mails to them have been answered withon 2 days. They really stand behind their products and with good reason. They are the best. Did I mention that they were willing to replace my amp for free if it broke down a second time?!?!

I have been playing about 5 years. I have gone through many changes in stlye and gear over this time. I started with a small combo then moved to a marshall half stack. Then I moved to a rack system tpe preamp/poweramp setup. That being too complicated to use all the time I went to a large fender Blues deville combo amp, and then to this bivalve setup. It's small enough to lug around for practice (although heavy as hell!) and it sund amazing without having 6 channels and 37 knobs and switches. It's simple and fun and inspiring to play. Before buying this amp I tested a few other amps as well as researched lots of other "boutique" amps. This one had the best features for the best price as well as a solid company standing behind it. a rare find. The only other amp I've tested that sounds this good is the bad cat hotcat at about twice the price. I still may buy the hotcat because of the ease of switching inputs between clean and dirty for ease of use live, but for the price I paid the bivalve can't be beat.
Would I buy it again? Yeah I think so. I am always experimenting with tone so I think I will always be trying new amps, but I have become very attached to the tone I get from this amp. Everytime I play it I feel inspired to create, and I think thats what a great amp does. It not only sounds good, but it feels good too.
If this amp had a midrange control and on the fly switching it would get a 10.

My BiValve is a 2003 and it suits my style of music perfectly. I play Blues, Classic Rock, Rock, Hard Rock, Alternative Rock and a little metal. This is a 30 watt single channel class A amp. It does have an effects loop (unlike the Univalve). Don't think a 30 watt is loud ? Go try one ! I really thought that I would try some tubes and settle into a particular combination and I would stick with it....but nooooooooooo....I actually change tubes all the time based on my mood.

My favorite tubes in it are EL34 types and my favorite preamp tubes in it are NOS mullard 12AT7's and NOS baldwin 12AT7's ( I snagged some of these Baldwins for $5.00 a piece...talk about a good value...extremely low noice / microphonics).

I also like so far the 6V6's / 6L6GC's / NOS 6L6's / 6550's. Each yield a different sound or attribute which the BiValve can capitalize on. It is so easy to swap tubes...Why not put in some 6550's when you need some clean head room or some loud tight compressed distortion with crisp highs. Why not slap it some EL34's to get a thick low end and one of my favorite 'power tube' distortions.

I like this amp just the way it is. Some people complain that the unit doesnt have built in reverb. This thing sounds so good, I don't miss reverb. The tone is so thick and true.

I am a Gibson Double humbucker kind of guy. I mainly play a Les Paul Standard, Gibson SG and a 1970 Guild S-100 thru the amp. The Les Paul sounds the best thru the amp as far as 'Tone'. This Amp with a my Les Paul makes for a really thick sound. If you like a truly overdriven sound (not that fuzzy stuff they call overdrive)this is the amp ! The amp has built in noice suppression that you can turn on or off. The amp has a bulit in hotplate so you can crank up the tubes but turn down the volume ! This is a really great feature, however, the more volume you soak up with the hotplate the less you will like the sound. Cut the volume half-way even 2/3's and it still sounds good....start going lower and the tone loses it's luster. You can't expect to get that thickness if you rob 90% of the volume. There is also a low-v / high-v switch for controlling the plate voltage on the tube to get increased volume...I personally prefer the low-v setting. There are two input jacks labeled 'more' or 'less'. The less is better for clean sound and the more is better for overdriven sounds. I could go on and on about this amp.

Check out http://www.univalve.net/forums/ for univalve / bivalve info / thoughts / opinions provided by other users.

Yes I feel I can depend on it. Backup tubes and fuses are probably all that one needs. A backup is always a good thing just in case something happened to the BiValve that was outside THD's control....like the bouncer smashed it several times with a baseball bat because you were hitting on his girlfriend !...I dont think the unit would fail on it's own accord. Any Questions ?

Doesnt get any better.

I have called asking questions a couple of times and THD's staff has always been helpful and courteous. Ed pointed me to a helpful forum:

http://www.univalve.net/forums/

Ed and Andy have posted alot of info about the amp on this forum and it appears they try to help all that need it. I have tried getting support from Fender and Crate and I would not call it support !

These guys are fantastic !

I don't know what the warranty is for this amp, but it is the most solid piece of equipment I own. It is built like a tank. If I ever have a problem with the amp, I am pretty sure THD will exceed my expectations.

I have been playing guitar for 15 years. I have a small home studio and some other amps, but nothing that compares to the BiValve. The BiValve is my first expensive amp and it is worth every penny. Expensive is a relative term. It is expensive compared to my Peavey Classic 30 or Crate VC50 2x12 combo. It is not that expensive when you compare it to some of the other makes & models on the market. If it was stolen, State Farm better Damn well buy me another one !

Why did I chose a BiValve over other amps in this price range ?

Besides the fact that it sounds fantastic !

1) The tube flexibility
2) The built in attenuator
3) The built in dummy load & variable line out
4) Attention to detail
5) Small footprint (nice for my cramped home studio)


It will probably take me years to explore all of the possible sounds that I can get from this amp...but I love it already.

This is an update to an earlier post. Have obtained 2 Mullard EL34-XF1 tubes along with 2 Mullard 12AX7 tubes. What a sound. You have to experience it to believe it. I use a Sparkle Drive or my TS9 to push the front end a little and it just sings. I am after a Blackmore/Schenker/Roth type of sound. The natural harmonics are incredible. Also have started using a set of KT66's I was able to dig up. Cleaner tone. Great "punch". Fairly loud. Very sensitive to attack.

Still experimenting. A word of caution though...Those with G.A.S. may aquire a new weaknes...T.A.S. tube aquisition syndrome!

Bought new in June 2002, ser#0069. On the surface, this may seem to be a simple, single channel tube amp. However, this is probably the most flexible amp I've used. Details are included in posts below...I can only say that every knob and switch is really useful.

Right now I'm using this with a '60s reissue Strat, and it sounds great. I'm using it in the more channel with Philips 5814A and Magnavox 12DW7 preamp tubes, and Philips 7581 and GE 6550 output tubes, for a cleaner sound with more headroom. With the volume pushing about 3/4 this moves from a more Fender clean to more of a Vox feel. With two 12AX7s and output tubes that clip faster (ex. EL34), it's got a lot of really toneful gain. Personally, I love the tone of this amp, and think that most will agree, although I don't hear it suiting a scooped metal lover. As others have said, this amp has the complexity and tone in a class with amps costing 2 and 3 times more.

I've been using this regularly without backup and have had no problems.

Excellent! Quick, courteous, knowledgeable.

It sounds and "feels" phenomenal, is very portable (but a little heavy), incredibly flexible, and very dependable.

Had the amp about 6 months - #125. Features noted below. I can't overstate the utility of the line out - you can use it to drive an effects processor/slave amp for a stunning wet/dry setup, or while recording, you can record the line-out in addition to miking the cab and mix the tracks to taste. Channel-switching and on-board reverb are about the only things I can think to add. I don't miss the reverb (I prefer studio-quality digital 'verbs to springs anyway), but the ability to switch between clean and dirty sounds on the fly would be useful for live situations.

Rig is thus: Fender American Deluxe Tele/Fender American Strat Plus/Paul Reed Smith Custom-24 -> BJFE Baby Pink Boost -> Fulltone Clyde Deluxe Wah -> SIB Varidrive -> Maxon OD808 -> BiValve Head -> THD 2x12 Cabinet. I run the line-out of the BiValve into a t.c. electronic G-Major, then into a slave amp for a wet/dry setup. I primarily use the BiValve for recording, and playing at home and in small venues.

The BiValve is simply the best-sounding amp I've ever played through. Certain amps may have an edge in one area or another, but the overall tone of the BiValve, coupled with the tonal flexibility of different tubes, control settings, and overall volume (with the built-in attenuator) makes this a studio dream machine. Wonderful clean tones, great high-gain Marshall-esque tones, and the best in-between crunch tones I've ever heard. This amp wasn't really made with ultra-gain metal tones in mind - you can get pretty close, but you might find you need some sort of overdrive pedal to get you there. Thirty Class-A watts is plenty loud for most venues.

Construction is top-notch. THD has a stellar reputation. That being said, I haven't had it long enough for my comment to have weight. I don't expect any problems, and I expect any problems I do have to be handled well (see below...) Would gig without a backup, although I would bring some spare tubes and fuses.

Absolutely top-notch. THD's reputation is well-earned in this area. If you want other opinions, visit www.univalve.net and read...

Been playing 16 years, mix of jazz, rock, blues, etc. Have owned a fair amount of gear and played through a lot of other stuff. I would replace this amp in a heartbeat. It's so easy to lose yourself when playing through this amp - the sound is that good. There are a lot of boutique amps out there, many of them outstanding products, most of them focused on one tonal area or another. The BiValve is a chameleon, able to adapt itself to almost any situation. I have not encountered any other product with the tonal quality and flexibility of the BiValve. I'm sold...

Class A all tube amp with built in attenuator as described by others ... it is very heavy ...

Probably the best sounding amp at any price anywhere: sounds very 3 dimensional and rich and basically beyond words ... after hearing this baby you will never touch digital toys :-)

It was brand new when I tested :-)

Nice guys at THD.

In the end I didn't buy it as it is very heavy and if I sclepp that and also a cabinet that's too much ... instead I bought the THD HOTPLATE attenuator that I use with my LIGHT combo (35lbs) Divine sounding class A 3 channel all tube $650 Ashdown Peacemaker 40 - Ashdown now sings and as it is class A the sound is almost as good as the THD BiValve and I have several channels etc ...

If I were younger and wanted THE TONE I would buy either this head or Peacemaker 50 head or Cornford Hellcat; the latter is ost expensive ($1499) ... but under $1k my Peacemaker rules ...

This is a "follow-up" review to my earlier post. I made a mistake in
calling the two inputs on the Bivalve "Rock" & "Roll." On the Bivalve, the two inputs are "More" & "Less." Other than that, I enjoy this amp more & more every time I play it!!

The amp is serial number 108. I play a mixture of blues, R&B and 1960's-70's rock and this amp does them all well. I've owned/played just about every "cool" amp out there over the years (including Marshall, vintage Fenders, Orange, etc) and the BiValve has the richest/fattest tone of them all! I don't really miss the reverb that much, but if Andy added it, he'd have a real winner! The 30 watts is plenty of power, in fact I am currently using two "JAN" 6V6GTs in it (to reduce power for practice sessions). Will run 2 RCA 6L6GTs for gig situations. Am running the amp thru a single 12" Celestion G12T-75 in a closed back cab...would love to have one of the 2X12 THD cabs but can't currently afford it! May also run the amp thru a 4X10 Slant Front Marshall Cab I can purchase for cheap!

Using mainly a Gibson '59 Reissue Les Paul Sunburst Standard with the "Burstbucker" pickups and lightweight stop tailpiece...sounds great with many of the old classic overtones that made the '59 Burst so famous...amp is very quiet and can generate a load of different sounds including the "full-tilt" boogie (ZZ Top sound). It also generates a nice crunchy rhythm sound on the "more" channel w/ the volume at about 9 or 10 o'clock...I use various OD pedals for taking solos...

no problems and don't expect any...this thing is built like a battleship!

responses from THD have been very timely!

I love this amp...it is a little heavy to lug around (but not as bad as a Marshall Super Lead 100! I think it is a wonderful addition to any "tone-hound's arsenal!"