Groove Tubes Trio Tube Preamp

I believe the Trio, combined with the user's manual, is more than adequate to get the user off and running.

This is where the Trio truly excels. I have read some of the previous reviews in which the users complain of the Trio's thin, untamed, "Scream" channel tone. Might I suggest using the 1+3 switch. By engaging both channels' eq and gain settings, I believe you will find the same amount of bottom end as the "Mean" channel. Also, this combination tends to refine the tone significantly. I played around with the settings last night and even after owning this unit for 10+ years, I am amazed at the tonal control and sonic versatility of this unit. Of course, I am using the Trio with a Groove Tubes D75 stereo amp. What an unbelievable, unbeatable combination. I agree with one of the previous reviews... If you can't find excellent, usable tones from the Trio, I would look elsewhere to discover the problem.

As I mentioned, I have had this unit for 10+ years with no reliability issue, ever. I re-tube every two years and have had nothing ever go wrong. As for using it with no back-up, I am probably tempting fate, but, I have never taken an extra amp to a gig. Also, I have never needed one, either!

I have made several inquiries with Groove Tubes' customer support staff. They are incredibly responsive to questions and advice and are never in a hurry to get you off the phone. They rock!

With this rig, I have played everything from metal to wedding / dance music. I have not yet encountered any style that this rig can't handle. My set-up consists of the following:
Groove Tubes Trio, Groove Tubes D75, Groove Tubes 4x10 cabinet, Rocktron Xpression, MIDI Mate controller, Dunlop 535Q wah, Heil Talk Box, Boss AC-2 Acoustic Simulator, Telex wireless, PRS Custom 22, Dean V, Dean Z, Schecter C1 Classics (2), Ovation Custom Legend.

I have been playing for 34 years and have owned and played through many amps; Peavey, Music Man, Lab Series, Fender, Kustom, Hughs & Kettner, etc... This is, by far, the best rig I have ever owned. All of the other, previously mentioned, amps have been sold or traded. I would never consider selling this rig.

If I had any complaint about this unit at all, it would be the weight. The combined weight of the Trio and D75 in the Groove Tubes birch rack would make any roadie run the other way. Unfortunately, I am my own roadie.

If it were stolen, I would hunt the offender down, get me gear back, have them prosecuted to the fullest extent of the law, and have "Make Me Your Bitch" tattooed to his forehead for his stay in prison.

This the 2005 25th Anniversary Edition with a chrome faceplate. But it should be identical otherwise. I bought it together with the footswitch.

This is not a review in the traditional sense, this is more of looking for the ultimate tone out of a great device. I tried ?tubetonening? the Trio in the search of the ultimate Tone.
My testbed is one of the 2005 ?25th Anniversary Silver Edition Groove Tubes Trio? which came stock with 5 GT 12ax7, which are in fact special tested and selected JJ ECC 83 S (ECC 83 is the European version of the 12ax7). The JJ is a Slowakian tube, which is known for its sweet top end, and is a copy of the famous TFK (Telefunken) ECC803 S. This is clearly a great choice, but that doesn?t work out the varieties of the three different circuits.
Tubetonening is now an issue for you if you want to work out the characteristics of the channels more or if you have the gain and/or volume settings at the extreme left end (e.g at 2,3, or 4)in your standard operation. In this case is amplification factor of the tube too high.
If you open the upper cover by untightening the screws, you see 5 preamp tubes. The first two from left ? called v1 and v2 ? are working in the Scream channel. The ?Gain? knob works between the first and the second stage of v1 (important to know that one 12ax7 has two independent gain stages in one glass container). With bringing in a lower amplification tube in v1, you have to go up with gain knob and get a more sensible dialing in, but give up the extreme settings. A lower amplification tube of a 12ax7 is a 5751 (70% of a 12ax7), 12at7 (60%), 12au7 (44%), 12ay7 (20%). In most application you can work with the first two, since the 12ay7 draws a lot of current and can cause trouble by overstressing low-wattage plate resistors (they can develop crackling noises.)
I found it pleasing to set a Mullard 12at7 (M8162 or CV4024 are identical) in v1 and a 5751 (RCA 5751 blackplates) in v2, this brings the over-the-top ?screaming? (think of a JCM 800 or 900) into a roaring ? a more vintage like distortion. The 5751 is a sweeter sounding tube, while the most 12at7 are very bright. I have a lot of 12at7 (and also the identical 6201) on hand but only the Mullard brings a full tone that I like for guitar. Another great combination is the legendary Mullard ECC 83 in v1 together with a RCA 5963 (special blackplate version of the 12au7) in v2.
Next is v3: The first half is the first stage of the Clean channel is covered by v3, while the second stage is on the first half of v5! With v3 you can influence the character of the Clean channel widely. The channel cannot be overdriven easily since the amplification rate was set very low to duplicate the 60ies clean sound with a 12ax7. Lot of folks like the more raw SVR/Texas sound which is achieved with ?hotrodding? the Fender Super Reverb clean. If you want this, you need a very strong Ecc83, this can be special ordered from some tube dealers. Then go with 10 on the gain and as much as you can on the Volume.
Otherwise you can dial in a more funky, mid scooped clean sound which is easily done with a lower gained TFK or a Sylvania / american made JAN Phillips or Mullard 12at7. Even a Dutch made Phillips (also labelled as Amperex and Valvo), a Tungsram or a EI is a good choice here ? the stock GT 12ax7 is too sweet for funky style.
The second stage of v3 it the first stage of the Mean channel. So a hot 12ax7 in v3 (for Texas sound) makes also the Mean channel more crunch up. I had the best results with Mullard 12at7 in v3 which makes the Clean Ch. bright ?n? cutting, but also the Mean Channel a bit softer with a more grainy distortion.
The v4 is now the second and third stage of the Mean Ch. which is a Cathode follower circuit. This is a special circuit found in Tweed Fenders and the first Marshalls. In theory this is a linedriver and buffer circuit, but in my book the differences in volume are small. This is doing more of compression and buffering than of influencing the amount of distortion or gain. So be sure using a tube brand which reacts smoothly on heavy compression in this slot. The vintage german tubemakers in their heydays tried to push the line of distortion in a preamp tube further away. So the TFK and the Siemens don?t take compression well, they become gritty and nasty at least, if they got a real load of input? not a good choice in this slot. The Mullard or a RCA 12ax7 on the other hand is well known for its capability to take lots of gain, therefore they would be a great choice in here. A 5751is too brown, a 12a7 too gritty and the 12au7 made it sound small IMHO. In conclusion the Mean channel has its very own sound with which you have to work on that specific sound, due to its circuit.
The V5 is the second stage of the Clean channel and the overall amplification of the preamp which calls for a clear and bright tube. The TFK, together with Sylvania and the Phillips are a good choice there. If you chose the SVR/Texas tone for the Clean I would look for a RCA or GE 12ax7 or the stock GT here.

All in all were my first impressions on the 2005 Trio that it has a not overly appealing, very clean 'Clean' and two similar nasty distortion channels. After a lot of tweaks i got a funky Clean, a Mean channel which is a syrupy kind of crunching up with hard playing (think of Jumping Jack Flash Song) and a vintage sounding distortion on Scream. That?s what I was looking for!
One word to the Scream Channel: If you choose the 1+3 option, the Gain knob of the Clean reacts as a smoothing down the overdrive of Scream. That means if you have the Gain knob the Clean full open, both options sound quite identical. If you have a lower setting (see my funky Clean setting), you have less distortion on the Scream. My fav is Clean Gain on about 5-7 for a vintage Marshall sound on the 1+3 option.
Another thought about NOS (New old stock) tubes and UOS (used old stock) tubes: I have both, I never had a problem with both. My UOS are mostly from Ebay, even from American dealers. I always looked on their number of deals and the comments about their deals. I was never let down and got great tubes for a reasonable price. Especially those RCA 5963 or 5751 Blackplates or the Mullard 12at7 are great and durable stuff - will last some thousand hours in this unit.

No problem so far, you hear some more humming while the tubes are heating up. But that dissapears in full operation.

Only dealt with the German Distribution Company.

After all the tweaks i like it very much. Its versatile and easy to work with. I would have liked some of the great GT 12ax7 M to come with this unit or a specific selection of GT tubes for each channel. This would have worked for most users greatly.

I've got a couple of strats and ernie balls going through this amp. I've tried it with a couple of different power amp sections from various tube amps but when I paired this with their D75S poweramp, wow. This is one of the best set ups I've had. For effects I've got a Chandler delay and a Peavey Valverb...simply amazing tone and feel. The clean channel sounds nice and tight. The Mean channel sounds like a nice older marshall, you can run it hotter but when it's sitting at about 5 on the gain, it's so smooth that you never want to put the guitar down.....besides that's what the Scream channel is for...over the top gain. It's not your Recto sound but that's getting pretty dated and a nice natural tube high gain sound is starting to come back.

Bottom line, you can beat a nice tube sound. There are many options when it comes to tube preamps, Mesa, Soldano, Marshall, Bogner, Egnater but the groove tube is by for the most simple and well balanced preamp. I've owned a Mesa Studio, Quad, triaxis, Soldano SP-77, marshall JMP1, and Egnater IE4 and M4 preamps but for the money, this amp does it all, 3 great sounds.

3 channels, each with their own gain, tone and volume control. You can mix channel 1 and 3 or just use 3 by itself. has a parallel effects loop with level control. 2 sets of outputs, one dry and one mixed with the effects loop. Pretty versatile in that each channel is very independant.

Built like a Tank.

Never had to deal with them.

I've been playing for about 17 years, wide range of styles. I've had my fair share of gear. One of the best preamps i've bought, definitely a keeper, especially because it was designed by the father of the Tube amp, Aspen Pittmen.

I am a studio and live musician and need to play different styles and different sounds. Sometimes I do not know before a session what I have to play - means I really need a versatile and easy and fast (time is money) adjustable amp. I am a proud Brian Moore Endorser and play these guitars exclusively. The Trio runs through a Rocktron Replifex and an old Intellifex and is powered by the Groove Tubes Dual 75 Poweramp, that I can very much recommend with this preamp. What I like on the Trio is that it is very flexible. This preamp sounds like a lot of vintage amps but is not f***ing digital, it is the real thing. Beside this you can find an own Groove Tubes sound which is very nice too. My favourite is that you can get the scream channel (...for distorted sounds) totally clean with the volume control of the guitar. This is excellent. Anyway there was no situation where I did not leave satisfied customers in the studio. To the guys who gave bad notes for the sound (...you will find deeper on this site): I really do not want to hurt anybody's feelings but if you can not get a good sound (any style!!!) out of this preamp you need to find the reason in your hands, you will definately not find it in the equipment, sorry guys!!!

Well, my Trio preamp is a new one, I bought it directly from the German distributor. It has (as you might have read already) 3 channels with passive EQ. There is a parallel FX loop and mixed outs and also a preamp out. It can be switched by a (optional) footswitch, (optional) midiboard or by a rackswitching system. Therefore it has a stereo and a mono output. Actually this is more than you can ask for.

This preamp, like the whole GT gear, is built for last a hundred years and more. It is in a rack and has been carried around a lot. Nothing wrong with it. Everything is how it is meant to be.

I had a question cc. the rackswitches. My first reply came after one minute!!! 1 hour later my problem was solved. I do not know a word for this - excellent is not enough. Aspen and his team are perfect and do not leave you alone after you bought something. I can highly recomment this company

Like I said, this one is worth the money. Actually it is a very good price if you compare it to other preamps. I first heard the Trio - D75 combination when I was making a test for a german guitar magazine. I swore myself that I will buy this combination and made it true. No need to look back, it was a wise decision. I own some more amps that I also like very much (Mesa Boogie, VHT, Soldano) but this one is my favourite.
Just one thing - excuse my terrible english :-)

No es deslumbrante. No tiene un nivel de salida alto. Gana en timbre mas que en pegada. Por si solo no uso ningun canal en solitario. Las distorsiones las acompa?o con overdrives como el Ibanez TS 9 o Tech 21 GT-2. El canal 3 sopla si no lo regulas bien. Para limpios incorporo un compresor Boss CS-3. He tocado Twins y he notado mas que en este la sensacion timbrica del previo. Tambien he tocado con el Triaxis. Al Trio lo situo entre el Twin y el Triaxis, timbre y pegada pero con moderacion. Hasta aqui parece que no me gusta mucho... pues NO !!! Cuando todo sin el Trio la guitarra suena hueca, sin sangre. El Trio es como Raul, el del Madrid, parece que no juega pero es el que gana el partido.

GT Trio preamp: 3 canales y un switch 3+1. Sin Midi. Volumen, ganancia y 3 bandas de EQ por cada canal. FX loop mono, con nivel de efecto. No puedo dar un 10 por no tener Midi. La opcion del 3+1 me gusta pero, al no poder activarla desde la pedalera, no es util.

Sin problema, pesado, robusto, indestructible, un tanque.

Intente comprar el circuito Midi y me pidieron un ojo y la cornea del otro. Me pille el Rockman Octopus y se acabo el problema.

Es muy bueno. Solo lo quitaria si encontrara otro parecido (Egnater, Custom Audio, Brunetti ). Es discreto pero resuelve.

i'm using this preamp with les pauls and its the fullest, smoothest, most harmonically rich, sweetest sounding, most 3D sounding preamp i've ever used. my musical style is rock. NO scooped mids crap. i'm into very technical music with complex rythms, time changes, etc. i like to experiment....but i'm a tone junkie. i will tell you right now that the tone out of any other amp can't be any better than this...only different. i really like bogner amps, soldano sounds good but i think the trio/dual 75 power amp has em beat. vht is great for really agressive sounds. don't get me wrong....i haven't tried every amp out there but i've played through enough to know what tone sounds like. i've had marshall jcm2000, mesa dual and triple rectos, peavey 5150, crate blue doodoo, orange ad30tc, fender hot rod deluxe, ada mp-1, ada mp-2, tubeworks real tube II, kasha rockmod II and kitty hawk quattro and the TRIO puts all of them to shame. i must mention that i'm using the TRIO with the groove tubes dual 75 power amp. that power amp is amazing (read my other review on that). you MUST use the TRIO with the dual 75 power amp to unlock all of the trio's potential. i used to use the trio with a mesa 20/20 power amp, which is definitely a good power amp but it can't touch the dual 75. i've used the marshall 9200 100/100 power amp and that thing is crap compared to the 20/20 and the dual 75.

3 channels, clean (fender blackface), mean (fender tweed), mean (modded marshall except way better) 3-band PASSIVE eq for all 3 channels, volume and gain for each channel, footswitchable via footswitch, rack switching system, optional midi, channel switching buttons on the faceplate

sometimes i wish it wasn't built so well because its HEAVY for a preamp!

answer all my questions right away!

i've been playing for about 7 years now. if this amp were lost or stolen i would most definitely save up for another one. i love everything about it except that its weighs more than any other preamp i've used. these preamps are rarely on ebay or harmony-central classifieds because no one wants to sell em. so if you find one for a good price then buy it or live in ignorance.

The amp is really easy to use. I like the simplicty of it. It took me some time to get the sounds the way I wanted them to be. You have to be a bit clever. The clean channel always sounds good, no matter what you do. The mean channel is great for blues and ac/dc like hardrock.
It took me some time to get the sound I liked from the scream channel. I didn't have a manual with it but the amp speaks for itself

I am using a gibson explorer and a Jackson KV, both with EMG pickups. I run the amp through a rocktron intellifex, a parametric EQ into a Kittyhawk poweramp(60/60. Like mentioned before I had some trouble to get the right sound from the scream channel. I couldn't get the same bottom end as on the mean channel. The Parametric eq works perfect to get the bottom end I like. I also use vintage 30 speakers and that smooths out the sound a lot. I've lost the irritating high end that comes with normal speakers. The good thing about the whole concept is that the sound doesn't get weaker by feeding it into the intellifex and the eq. The hush in the i-fex keeps the noise down. I play a wild mixture of southern rock and metal and I can get any sound I like. This is the best amp I ever owned. I used to play Marshall JCM 800 but I like this amp a lot more.

I never had any trouble with the amp. I toured with it, without having a backup, I know, it is like cursing the gods, but I never had a problem with it.

I never dealt with the company, so I don't know.

Like I said, I play a mix between southern rock and metal. That means I have to chance my sound a lot. The Trio does it. It took some time to get the right sound for the metal stuff but I am totally satisfied with it now. It noticed over the last 15 years that it is often a certain combination of things that make it happen. If it would break down or stolen I probably would buy it again. Maybe I would go back to a head. Cause I noticed that a lot of pre-amps sound like crap. They sound to compressed. I read someone had trouble to get the right balance between the channels. I don't get that, I think that is one of the good aspects of the amp. I noticed that the overdrives sound a lot better with vintage 30 speakers. And of course, you have to play it loud! A tube amp starts to rage at loud settings. There is one thing I would like on it: the bottom end from the mean channel in the scream channel. Nevertheless I love this amp and it is a joy to play. I played a lot of amps over the years and this is definately one of the best pre-amps I ever owned.

I run my Trio into a 50-watt 6L6 power amp. I use Fender Strats, one with the Texas Special and Pearly Gates configuration and the other with vintage reissue single coils. A few years ago I sold all my pedals and went with rack gear. I had been using a Full-Drive 2 and the ?70 pedal for my over drive and fuzz. I could never get the sound I wanted out of the Fulltone stuff (came close with the ?70 pedal), so I sold them both and bought the Trio. For basically the same money as the two pedals, I got a professional all tube preamp that can cover virtually all the sounds I was looking for. I switched out the GT 12AX7s that came with the unit for 5 JAN Philips 12 AX7s. This smoothed out the gain (without reducing it) and made the preamp breath even more. The clean channel is pure glass, the mean channel can do a nice smooth overdrive up to more drive than a fender tweed can muster, and the scream channel can go from a fat rich overdrive to hotrodded high gain with endless sustain. Hey, that rhymed.

The Trio is an all tube 3-channel preamp with 5 12AX7 preamp tubes. This Trio has the added feature of a toggle switch to combine the clean channel with the scream channel. Trio?s built after 1992 have this feature. The channels are voiced to sound similar to Clean = blackface fender (glassy clean), mean = tweed fender (mild to strong overdrive with pronounced mids), scream = (strong overdrive with more saturation, compression, and sustain). Each channel has passive tone controls for bass mid treb with gain and volume controls. The passive tone controls are very effective and interactive and allow for substantial variations in tone with the slightest tweak. You can select the 3 channels via buttons on the front panel or the three-button foot switch. There is a parallel stereo effects loop with mix level control. There is a provision for midi switching (my Trios does not have the optional midi insert card) and rack switching. This preamp has all the features that I was looking for.

Old GT equipment seems to be built very well. My unit was probably built between ?92 and ?95 and it shows no signs a fatigue. The steel chassis is heavy. This thing is not plastic. Seems very reliable. I have had mine for about 3 years with no problems.

I emailed (probably should have called) when I got this thing because mine did not come with a footswitch (gotta have a footswitch). They did not have any old stock footswitches at that time and the Trio was not in production (they have since brought it back). They said there was no real difference in the footswitches manufactured over the years for the Trio. Wrong. I got one off eBay that was for the model without the channel 1&3 blend toggle. It would not switch my Trio (any Trio built after ?92). In their defense, they had told me where I could get one from one of their dealers. But no, I had to try to get a deal on eBay. So now I have 2 footswitches. One works with my unit and one doesn?t. Anyone need a footswitch for a Trio built before 1992?

This is an awesome sounding preamp. I will probably never sell my Trio. It gives me so many usable sounds. I am not sure why a couple of users below were dissatisfied with the Trio?s sound. This is certainly not a thin sounding preamp and to compare the sound to an inexpensive digital device seems silly. I think it may be that tubes are not for everyone. Some people prefer the sound of digital distortion. That is fine. I still have my DS-1 ($29 bucks worth of pure shred fun). But if you are looking for a professional tube preamp sound with tons of flexibility, the Trio is a strong choice. Especially used.

I'm running this with a tele. Might be that it would have sounded better with humbuckers. But my tele is not a small and thin sound, it's pretty big. Have to say that the sound was very disappointing - clean sounded good, but mean channel was thin and tinny, and no matter how much I fiddled with the EQ, I couldn't get the fat sound I was looking for. It sounded messy and undefined. I am running this with a Boogie 50/50. I have never had problems getting a good tone before, I tend to instinctively know how to get a good sound from an amp. But this foxed me. The scream channel sounds overly compressed and I've tried for some time to get a nice sound. Sounds like a cheap Boogie, with a zoom. I found it very hard to get a balance between the three channels. There is no common ground, which makes it very hard to bring together a distinctive sound. I have to say that I have found this amp completely unenjoyable. However, I know someone with an older Trio who has got a great sound. I've checked valves, maybe need to change them to get the sound I'm looking for. COuld be that my Trio is a dodgy one.

This amp was made in 1999. Comes with the Scream/Clean Switch. In theory had the flexibility I was looking for = clean, drive, heavy distortion. Has midi (no idea how this could be imcorporated) effects loop, etc. I need an amp with a good clean sound, a cleanish slightly driven sound, like SRV, and a heavier sound - Raucous, but not metal.

No problems, but the plug broke on the channel switcher pedal.

Never contacted them, but have thought about going round there to give the guys at GT a good kicking.

Been playing 12 years. Am selling this box and going back to basics. This promised so much (sounded pretty good in the shop) but delivered so little. It's hard to beleive that such 'good 'gear could sound so bad. Maybe one of the other reviewers could give me some tips as to where I'm going wrong? How do you do it guys? Maybe it's because they are looking for a different sound from me - I'm not into metal, I like rounded, chimey clean sounds (fender twin), slightly driven sounds (like a driven VOX AC30/Matchless) and a more raucous sound, like a Tube Screamer/vintage Marshall type vibe. Sorry GT, this wasnt it, and I'm skint now!

Three channels, each with it's own push button to get you there. The controls are common to all guitar amps. Bass, mid, treble, gain and volume. Though the controls are minimal, they have great effect. Mines a very old one with no effects loop, so It's basically one 'in' and two 'outs'. Simple but effective is the key to this one.

Using with PRS custom 24, and loads of stompers, but mainly line6 delay and modulation modellers. various speakers, but most commonly a celestion vintage 30, 2x12 cab. The first thing everyone notices about ths amp is how noise free it is. no hiss, no hum. But the sounds it doesnt make are, then over shadowed by the sound it does.....awesome! I'm using the trio into the Groove tubes D75 power amp. It's dynamic and clear in every style. Each channel is very different, and within each channel is another great range of tones. The clean sound has amazing clarity, even on 'darker' settings. this clarity is not at the expense of depth. The low end is ample, with some to spare. The Mean channel is great is very responsive to dynamics, it 'breaks up' when I play hard, in a flattering way. The Scream channel has all the rock/metal tones i need. it can sound very aggressive, but with a lot of 'class'. Kind of like the queen swearing. It has the mega filth, and harmonically rich sound of a Mesa Dual rectifier say, but it wins over that in my opinion. I really like amps that respond to player dynamics, this amp does it even in very high gain settings, I hit harder - it gets louder and bigger. I really like that. I also use a boogie MK3 head, this is a good amp, but I do prefer my groove tubes. When I put my effects in the loop of my boogie, I loose some volume and top end when they are on. I use the same effects between my trio and D75 with transparency. I assume this is to do with the impedance of the loop in the boogie. the trio is harmonically rich and SO dynamic. would like some more 'grrr' arounf 80hz for the down tuned metal stuff which would make this a 10/10.

ah! you never know when the gremlins will strike. I would take a backup wherever possible. But I'm sure it's made to last. no niggles yet.

Can't find a UK distributor at the moment. guess it's not GT's fault though. wouldn't like to have to find someone to reapir it!

The sounds I get from this setup are great. I use it mainly for Metal stuff. not off the 'scooped mid' variety. I need a good clean sound, a crunchy 'just breaking up' sound, and a "I think the devil wrote this riff" sound. I was happy with my boogie before I used this, and the boogie is a great amp. But this is much more refined. No one seems to know what it is, they think it looks like something from a WW2 tank, used for communication! but it makes a dual rectifier with a 4x12 sound SMALL in comparison. This amp breathes, cries and screams, but never farts.