advice: 6L6 hextet for SUper Twin head for bass guitar

cyclecamper · 12:59 AM

This Super Twin I converted into a head cabinet for bass guitar came with 4 Ruby 6L6GCMSTR which I think are relabelled russian tubes of some kind, and 2 Groove Tubes GT6L6S with power-match code "7" which I think are relabelled JJ tubes.

They were in the wrong sockets, so push was 3 Ruby and pull was 2 Ruby and 2 Groove Tubes.

I want to use this for bass, so power matters much more than breakup mode.

What's my best course of action? Stick with what I have and stick them in the correct sockets so push & pull at least have the same complement? Trade someone the GTs for a pair of Ruby? Look for 4 GTs w/ code "7" and sell the Rubys? Look for old made in the USA tubes?

ArcticBreaze · 16th December 2012, 04:59 AM

I'd buy 6 new ones from here
6L6GC, JJ | Antique Electronic Supply LLC
they will match 6 up for you then you no what you've got, unless you hav access to a tube testor and trying to find 6 second hand that match close could be a big ask.

GeorgK · 16th December 2012, 08:40 AM

If vou do not have a chance to test the tubes for wear and matching this is difficult to answer. If they do not *look* too used I personally would give it a try and put equal combinations into each half of the power stage as you suggested, turn the "matching" pot to mid position and go.

JRGuitarGuy · 16th December 2012, 08:57 AM

I don't know man I heard bad things about the JJ 6l6gc's, What you have could be Chinese or the JJs or some other Russian Variant. You could look into the new Tung-sols I thought those sounded good as well as the SED/Svetlana

JRGuitarGuy · 16th December 2012, 08:59 AM

Those old RCA black-plate 6L6's have some real Magic going on inside them but you are gonna pay for it

JRGuitarGuy · 16th December 2012, 09:05 AM

Its up to you I would just experiment with different ones then you could find what suites you're tastes, I'm just scared of current production tubes, I have had some nightmares or it was just really bad luck lol

GeorgK · 16th December 2012, 09:14 AM

Had not too good experience with JJ either. If they withstand the first three months or so they may be as durable as any other brand tube, but I had too many failing within a few days and therefore stopped using them. The ones in the the super twin are not really new as I understand, so why not in this case. Anyway, it depends on how much you are willing to spend.

JRGuitarGuy · 16th December 2012, 09:43 AM

Yeah lots of the JJs dead out of the brand new boxes etc lol but usually if they make it past that 3 month point they are some keepers lol I have 1 JJ ecc83s that sucker is still going its like 3 or 4 years old I went through like 10 of them over the years some dead right out of the box others would last a few days or a month etc lol. Their 6v6s is kinda a hit and miss though they sound pretty good but they will rattle themselves apart lol

JRGuitarGuy · 16th December 2012, 09:51 AM

I'm interested in trying something different myself though the JJ eec83s had good gain but I found its kind of hollow/narrow on the low end and harmonics are nothing special, they seem to have less Edge too. I miss some of those old Chinese 12AX7s I had, those were some edgy bastards lol bright but man they could cut buddy lol, just more of a pissed off sound lol

JMFahey · 16th December 2012, 11:29 AM

What's wrong with actual measuring vs. guessing?
Scope the amp driven to *just* clipping and check:
1) how much it's actually putting out. Anything above 120W RMS is excellent.
2) symmetry.
If symmetrical clipping within 5% or 10% (which I doubt is happening now , except by sheer chance), fine.
If not, do the musical chairs game:switch right/left a couple until you get a match.
Wit the bias balancing pot set to middle, of course, so you are actually matching thge tubes themselves.
When real close, only then use the pot for final tweaking.

16th December 2012, 12:47 AM	#1
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	advice: 6L6 hextet for SUper Twin head for bass guitar This Super Twin I converted into a head cabinet for bass guitar came with 4 Ruby 6L6GCMSTR which I think are relabelled russian tubes of some kind, and 2 Groove Tubes GT6L6S with power-match code "7" which I think are relabelled JJ tubes. They were in the wrong sockets, so push was 3 Ruby and pull was 2 Ruby and 2 Groove Tubes. I want to use this for bass, so power matters much more than breakup mode. What's my best course of action? Stick with what I have and stick them in the correct sockets so push & pull at least have the same complement? Trade someone the GTs for a pair of Ruby? Look for 4 GTs w/ code "7" and sell the Rubys? Look for old made in the USA tubes? Last edited by cyclecamper; 16th December 2012 at 12:59 AM.

16th December 2012, 04:59 AM	#2
ArcticBreaze diyAudio Member Join Date: Dec 2010 Location: Oamaru	I'd buy 6 new ones from here 6L6GC, JJ \| Antique Electronic Supply LLC they will match 6 up for you then you no what you've got, unless you hav access to a tube testor and trying to find 6 second hand that match close could be a big ask. __________________ Fat Tubes For Fat Sounds

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16th December 2012, 08:40 AM	#3
GeorgK diyAudio Member Join Date: Jan 2005 Location: Vienna	If vou do not have a chance to test the tubes for wear and matching this is difficult to answer. If they do not look too used I personally would give it a try and put equal combinations into each half of the power stage as you suggested, turn the "matching" pot to mid position and go.

16th December 2012, 08:57 AM	#4
JRGuitarGuy diyAudio Member Join Date: Oct 2012	I don't know man I heard bad things about the JJ 6l6gc's, What you have could be Chinese or the JJs or some other Russian Variant. You could look into the new Tung-sols I thought those sounded good as well as the SED/Svetlana

16th December 2012, 08:59 AM	#5
JRGuitarGuy diyAudio Member Join Date: Oct 2012	Those old RCA black-plate 6L6's have some real Magic going on inside them but you are gonna pay for it

16th December 2012, 09:05 AM	#6
JRGuitarGuy diyAudio Member Join Date: Oct 2012	Its up to you I would just experiment with different ones then you could find what suites you're tastes, I'm just scared of current production tubes, I have had some nightmares or it was just really bad luck lol

16th December 2012, 09:14 AM	#7
GeorgK diyAudio Member Join Date: Jan 2005 Location: Vienna	Had not too good experience with JJ either. If they withstand the first three months or so they may be as durable as any other brand tube, but I had too many failing within a few days and therefore stopped using them. The ones in the the super twin are not really new as I understand, so why not in this case. Anyway, it depends on how much you are willing to spend.

16th December 2012, 09:43 AM	#8
JRGuitarGuy diyAudio Member Join Date: Oct 2012	Yeah lots of the JJs dead out of the brand new boxes etc lol but usually if they make it past that 3 month point they are some keepers lol I have 1 JJ ecc83s that sucker is still going its like 3 or 4 years old I went through like 10 of them over the years some dead right out of the box others would last a few days or a month etc lol. Their 6v6s is kinda a hit and miss though they sound pretty good but they will rattle themselves apart lol

16th December 2012, 09:51 AM	#9
JRGuitarGuy diyAudio Member Join Date: Oct 2012	I'm interested in trying something different myself though the JJ eec83s had good gain but I found its kind of hollow/narrow on the low end and harmonics are nothing special, they seem to have less Edge too. I miss some of those old Chinese 12AX7s I had, those were some edgy bastards lol bright but man they could cut buddy lol, just more of a pissed off sound lol

16th December 2012, 11:29 AM	#10
JMFahey diyAudio Member Join Date: Mar 2009 Location: Buenos Aires - Argentina	What's wrong with actual measuring vs. guessing? Scope the amp driven to just clipping and check: 1) how much it's actually putting out. Anything above 120W RMS is excellent. 2) symmetry. If symmetrical clipping within 5% or 10% (which I doubt is happening now , except by sheer chance), fine. If not, do the musical chairs game:switch right/left a couple until you get a match. Wit the bias balancing pot set to middle, of course, so you are actually matching thge tubes themselves. When real close, only then use the pot for final tweaking.