ConanTheLibrarian
Joined: Dec 27, 2018
Posts: 7
Chicago
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Posted on Jan 26 2023 03:26 PM
Hey gang!
I've got a Gomez G-Spring 6G15 which I absolutely adore. I have one tiny peeve though, and it's that I feel like the preamp clips just a HAIR too much/too soon for my liking. Its mostly just with my humbucker equipped guitars. But my slightly hotter P90s doo this too (just not as much)
Its loaded with an RCA 6K6, Jan Phillips 12AT7 and an RCA Black Plate 12AX7.
I was wondering if I would gain any headroom from installing a 6V6 in the power(would I have to re-bias)? Or possibly some other preamp tubes? Maybe it is the nature of the beast and I can live with it, but I wanted to pick your brains about any possible experiences or suggestions.
Thanks!
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Fady
Joined: Mar 07, 2010
Posts: 2274
North Carolina
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Posted on Jan 26 2023 05:37 PM
Sweet piece of kit you’ve got, ConanTL!
I’ve got a few suggestions/opinions/experiences that I’m happy to share. I too have the G-Spring (two actually).
First, for the G-Spring and any 6G15 outboard unit, the SG101 Wiki is a great reference. I find myself pouring over it a couple times a year it seems.
Next, one persons lower headroom is another’s perfect bloom. Ones higher headroom is another’s sterile. Also, everything between the string and the speaker has/can have an impact to the result you are after. For this kind of experimentation, I cannot recommend simplifying thru reduction enough. Guitar -> G-Spring -> Amp. Ideally with reasonable length cables (like 10-12-15 ft or so tops to G-Spring and like 6 or 10ft tops to amp.
That all said, I’ve noticed more impact on what I think you are talking about by rolling tubes in for the 12AX7 spot (far right when looking at the unit from the back/open side). Going lower in gain on that tube can look like different 12AX7’s (eg: I find Tung-Sol 12AX7 to be some of the hotter/harsher ones in this application, others less so). It could also be putting in a 12AT7 or the like. I’ve also tried a JJ 5751 in that spot and got results that to me sound like something you might want to experiment with.
In my G-Spring tube rolling experimentation, putting in a 6V6 rather than the 6K6GT can produce some interesting results. I got a Japanese one by accident that sounds marvelous. That said, I got more volume and punch in those swaps than perceived clean headroom in the G-Spring. YMMV. My 2¢… start your tube swap exploration with the 12AX7.
Good luck, enjoy the journey and let us know what you experience!
— Fady
El Mirage @ ReverbNation
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Fady
Joined: Mar 07, 2010
Posts: 2274
North Carolina
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Posted on Jan 26 2023 05:56 PM
PS - no need to worry about biasing if you swap a 6V6 for the 6K6GT.
— Fady
El Mirage @ ReverbNation
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DeathTide
Joined: Apr 13, 2018
Posts: 1379
New Orleans
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Posted on Jan 26 2023 06:12 PM
I would also start with trying a 12au7 or 12at7 in that V1. I'd guess it's the hot pickups.
I would also say if nothing else works, changing the value of the cathode resistor could give you more headroom. But it could also give you more noise. I have no idea how to figure out the correct value. There are calculators for that though. Better if you can just change the tube and be done with it.
— Daniel Deathtide
Last edited: Jan 26, 2023 18:13:57
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ConanTheLibrarian
Joined: Dec 27, 2018
Posts: 7
Chicago
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Posted on Jan 27 2023 01:53 PM
You guys are such a great help! Thank you so much.
I'm gonna start with tube rolling. I don't wanna mod the amp at all and totally agree @DeathTide, just tubes and be done with it.
@Fady That SG101wiki is a fantastic resource! I didn't even know it existed. But I can understand about the subjectivity of "headroom" and I should have clarified a little more about my signal path and all that jazz. My bad.
I've tested all my cables going straight into the amp, sans G-Spring and its all clean as a whistle. It usually just goes guitar > 6ft cable > G--Spring > amp.
My amp has plenty of headroom at 100w so its not that the tank is making the amp itself clip. (Fender Custom Shop Tone-Master head and cab with JBL D120s)
What it sounds like is the reverb coming from the G-Spring is getting some distortion somewhere. It sounds cool! Just a little hair on the drip and reverb itself when I hit a hard chord, but I wanted to see if I could tame that. My minds eye wants Twin Reverb or Super but with more splash? Could definitely be my pickups though. I know the reverb circuit is placed different in those amps and that could also be a factor.
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