raketenmann
Joined: Mar 05, 2021
Posts: 7
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Posted on Mar 05 2021 02:53 PM
hey guys
I recently bought a used Gomez The Tahitian Amp used here in Switzerland. It's a fine amp I really like, but basically don't find any information about it on the internet, except on this page it seems that some people do own Gomez amps.
I would really like to replace the JJ tubes it git with some NOS tubes, last time I did this the improvements were spectacular. But since I don' know which tube is responsible for what purpose, it's not so easy to choose the right tubes. I know that sometimes a 12AX7 and a 12AU7 or a 12AT7 are interchangeable and that I can fine tune the sounds I like, bit for that I need to know, wich tubes is doing what. Can someone probably help me with that? Thanks so much!
So here is the tube chart:
V1 6L6GC
V2 6L6GC
V3 6L6GC
V4 6L6GC
V5 12AU7
V6 12AX7
V7 12AX7
V8 12AT7
V9 12AX7
The only thing I know for sure is the 6L6's being the power tubes and need to be matched...
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eltwang
Joined: Feb 26, 2008
Posts: 540
Copenhagen, Denmark
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Posted on Mar 05 2021 04:02 PM
Hi, I have the same amp. It's a cool amp.
V1 is the preamp/ first tube on the right (you call it V9)
V2 not sure but think it must reverb circuit (you call it V8)
V3 not sure but think it must reverb circuit (you call it V7)
V4 Tremolo (you call it V6)
V5 phase inverter/is the tube closest to the power tubes
The amp has a solid state rectifier.
I run mine with only two 6L6 tubes that takes the power down to 50 watts.
Also I have a 5751-tube in V1 for less gain. Apart from that I wouldn't change between the 12ax7, 12au7 or a 12at7. They all have very different gain.
JJ, EH and Tung-Sol tubes are fine modern tubes. I know Dario used NOS 12ax7 RCAs. Your amp may even have one in the V1.
— El Twitter
El Ray
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El Twang on YouTube
Last edited: Mar 05, 2021 16:25:23
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duncanjames
Joined: Dec 20, 2011
Posts: 150
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Posted on Mar 06 2021 02:45 AM
I've also got one, and can confirm what El Twang said. V1 is first gain stage, V2 is reverb driver, V3 reverb recovery and gain stage, V4 tremolo, V5 phase inverter, and the rest 6L6 type power tubes.
While some amps seem to have used a 12ax7 reverb driver at one point, it's generally accepted that they can't handle the driver current like a 12at7 can. Some of the other preamp tubes you can maybe swap out, but I think you'd be happiest with it as it is.
While not entirely accurate, you can kind of look at it like a 100 watt Princeton Reverb. I think I remember something about the tremolo being more Tremolux derived. Any experience you might have with one of those might help you out with tinkering here. Still, I think you'd like it best as is. It's a really great amp, and it's too bad they couldn't have caught on more.
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raketenmann
Joined: Mar 05, 2021
Posts: 7
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Posted on Mar 06 2021 04:53 AM
Hey I thank you so much. Now I see a lot clearer!
Oh Wow - well I think I need to look inside then to check if the preamp tubes are already some NOS RCA's, I actually didn't check them.
Well, I am really not a specialist in tubes - some say JJ's are fine, some say the suck. My experience was that when my amp tech did change the tubes on a 60ies Simmms Watts, the JJ's EL34 were faulty and were blowing the fuse everytime I played it loud, so they needed to be replaced. I also sent a friend to the same apm tech to change the tubes of his Marshall JCM2000 - he had the exactly same problem: faulty new tubes.
As I already told: my exerience in my Fargen MiniPlex Amp were spectacular: I replaced the two EL34's from JJ with a pair NOS from the 70ies. I was able to compare them side-by-side with the original ones, the Teslas and a pair of Philipps (the holy grail EL34) - There were real differences and for me the Teslas sounded the nicest.
Actually, what I did there also, was replacing a 12AX7 against a 5751: I REALLY liked that and it was the biggest difference in the Fargen tube-swapping-afternoon - so I probably will test out this tube in the V1 position as well!
Thank you so much so far - such a great community, such great amps these Gomez - I'm very happy!
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eltwang
Joined: Feb 26, 2008
Posts: 540
Copenhagen, Denmark
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Posted on Mar 06 2021 03:49 PM
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raketenmann
Joined: Mar 05, 2021
Posts: 7
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Posted on Mar 07 2021 07:04 AM
I‘m using it as a studio amp, and there I lbly got a 77 Marshall 1981 4x12 Cab. I‘m actually more of the British speaker guy than american speaker guy.
In my cab theres 2 of the original Celestion G12H 55Hz 30-watt blackback speakers, which actually should be fine vintage speaker, bit are harsh kn the 2.5 to 3k range, what I don‘t like. So I replaced ond soeakee with an Eminence Wizard: a very nice speaker, british style, very midrangy, smooth bass, no harsh top, my first choice at the moment. And the last of the speakers is a Eminence Texas Heat, wich is an american style speaker, very dark. I heard this speaker on a youtube channel with some excellent hi-gain sounds and really liked the growly midrange, although I didn‘t have luck with it so far. Probably the speaker needs to break in more or just doesn‘t match well with a closed back cab, its just too dark...
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raketenmann
Joined: Mar 05, 2021
Posts: 7
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Posted on Mar 25 2021 12:49 AM
Hey there
Can someone please help me out.
I just did replace all the tubes on my Tahitian with NOS tubes. Before I did so, I did pull all of the old tubes to see what brands are in there and put them back to place. Since then I have a strange behavior wich didn't go away with the new tubes.
The amp does a very hard and very nasty distortion that comes with the initial attack of the strings and suddenly dissapears with the sustain of the sound. The distortion only appears on high volumes. When I disconnect the reverb tank, its almost gone, but the level is also lover without the reverb tank in the circuit. Also the Tremolo sounds very distorted. The deeper I dial in the tremolo, the more distortion I get.
Any suggestions what to do?
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eltwang
Joined: Feb 26, 2008
Posts: 540
Copenhagen, Denmark
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Posted on Mar 25 2021 04:50 AM
First of all you must get a tech to set the bias in the amp when installing new power tubes. Also check that all pre-amp tubes are in their correct places (12ax7, 12at7 and 12au7). Maybe one of them is faulty.
Did your tremolo sound all clean before? The tremolo in my amp is quite distorted too and I can't set the intensity very high.
— El Twitter
El Ray
El Ray on Bandcamp
El Twang on YouTube
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raketenmann
Joined: Mar 05, 2021
Posts: 7
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Posted on Mar 25 2021 10:25 AM
eltwang wrote:
First of all you must get a tech to set the bias in the amp when installing new power tubes. Also check that all pre-amp tubes are in their correct places (12ax7, 12at7 and 12au7). Maybe one of them is faulty.
Did your tremolo sound all clean before? The tremolo in my amp is quite distorted too and I can't set the intensity very high.
I did have the tech here to adjust the BIAS, this is all set, but he didn't have enough time and the equipment to check where the problem is.
I think the Tremolo was a bit distorted even befor the tube change, but this nasty distortion that seems to have something to do with the reverb wasn't there befor I first did pull all the tubes to see what types are in there, since then the problem is here, with both old and new tubes. I need to check if by accident I switched two tubes, but it should not be the case...
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eltwang
Joined: Feb 26, 2008
Posts: 540
Copenhagen, Denmark
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Posted on Mar 30 2021 04:44 AM
Did you figure out what the problem was, raketenmann?
— El Twitter
El Ray
El Ray on Bandcamp
El Twang on YouTube
Last edited: Mar 30, 2021 04:44:35
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raketenmann
Joined: Mar 05, 2021
Posts: 7
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Posted on Mar 30 2021 04:55 AM
eltwang wrote:
Did you figure out what the problem was, raketenmann?
Thanks for asking back. I found the problem - but not the solution. It is clearly a problem with the reverb driver tube or the whole path. When I remove the reverb driver tube (12AT7), then the amp works just perfect. With the reverb driver tube inserted, the amp start with the nasty distortion at around 6 on the Volume. If I turn the Volume to the max (10; I can because I have a power brake), then the distortion dissappears.
This all occures even with the reverb completely down and also disengagedwith the pedal.
I also tried with the old tube that was sitting in there before I changed tubes: Same problem. So right now I'm just running the amp without the reverb tube, cause I want that nice blackface overdrive and don't need the reverb. But in the future I will bring it to the tech...
The tremolo I think is OK, this just has a sort of a dirty character, wich I actually like, but it works fine!
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Nitro
Joined: Mar 05, 2021
Posts: 6
Sacramento Area, CA
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Posted on Mar 30 2021 12:15 PM
So the 12AT7 is usually a good choice for the reverb (especially for surf). Is the old tube a 12AT7 as well? If you have a 12AX7 maybe try that in there and see?
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eltwang
Joined: Feb 26, 2008
Posts: 540
Copenhagen, Denmark
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Posted on May 02 2022 03:08 PM
How did it all go, Raketenmann? I just powered mine up at home through a 4x10" Ampeg Bass cab. Sounds great.
— El Twitter
El Ray
El Ray on Bandcamp
El Twang on YouTube
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raketenmann
Joined: Mar 05, 2021
Posts: 7
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Posted on Jun 06 2022 09:00 AM
eltwang wrote:
How did it all go, Raketenmann? I just powered mine up at home through a 4x10" Ampeg Bass cab. Sounds great.
Hey there
Sorry for the late reply... I almost forgot about this post here and just came back by accident.
Hey, I just did let the problem be and used the amp without the reverb in the studio. But jsut laste week I took the amp back home with the idea to get it fixed by a tech. So first I just wanted to try out the amp again and see if I can replicate the problem after a year. Well, I just had the chance to test the amp for 5 minutes, but so far the nasty distortion from the reverb driver is no longer there  Sometimes time will heal wounds as well, haha. Well, I am pretty sure that the tube socket has some sort of a problem, but right now, the tube sits i there happily and I will leave it that way and just play the amp a little more!
Well, there's still the distorting tremolo, still not sure if this need to be this way or of it is the same problem, the tube not sitting perfect in the socket... I don't know.
best regards from Switzerland!
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