#1
I have one kldguitar GT5HR amp head. it is 12ax 7, 6l6 class A SE guitar amp I want to replace 6l6 by EL34.
Could I replace 6L6 with EL 34 directly? or I have to change some ting in bias , or Out put transform?
what different between 6l6 and EL34.
#2
Ask a trusted tech, I only see 1 power tube in that picture, so I'm guessing it's self biasing. Some amps (Self biasing or not) can switch between EL34 and 6L6 with no problems, others might require a resistor changed.

If you don't know of a trusted tech, ask Bob from eurotubes, he's a helpful dude and wont just try and palm off JJ's on you.
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#3
Quote by Jesstaa

If you don't know of a trusted tech, ask Bob from eurotubes, he's a helpful dude and wont just try and palm off JJ's on you.


+1, Eurotubes is extremely helpful
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#4
My opinion is that you need to go get some training in the basics of amplification and quit relying on UG for all of your 'How To' questions. Also, most of us here have never even heard of that amp so try contacting the manufacturer.
#6
Converting an amp from 6L6 to EL34's is rarely worth the trouble, especially if your goal is to have headroom. EL34's break up sooner than 6L6's.
Tastes like chicken, if chicken was a candy.
#7
um what trouble? most of the time it's just switch tubes and rebias.

and if he is switching to EL34s, he wouldn't be looking for more headroom.
#8
Quote by al112987
um what trouble? most of the time it's just switch tubes and rebias.

and if he is switching to EL34s, he wouldn't be looking for more headroom.


Most of the time on what amp? I certainly couldn't just slap EL34s in my Peavey.
Tastes like chicken, if chicken was a candy.
#9
Quote by ConfederateAxe
Most of the time on what amp? I certainly couldn't just slap EL34s in my Peavey.
you couldn't just slap a new pair of 6L6s in most 6L6 amps either. Your Peavey is not most amps.

are you going to tell people that most amps don't need a rebias when you swap tubes too?
Last edited by al112987 at Nov 19, 2009,
#10
Quote by al112987
you couldn't just slap a new pair of 6L6s in most 6L6 amps either. Your Peavey is not most amps.

are you going to tell people that most amps don't need a rebias when you swap tubes too?


Okay, let's clear this up. I dunno where the hell you're getting your argument from.

If you have an amp that runs 6L6's, and you want it to run EL34's, in most cases you have to make a modification to the circuit board, which is rather extensive and for tone purposes, unless the majority of the amp's tone comes from the power tubes, you're just wasting your time and energy. I mentioned nothing about biasing. Biasing tubes should be an outright given.
Tastes like chicken, if chicken was a candy.
#11
do you even know what change you have to make on the circuit board? or what is required to switch to EL34s?

The only board change you need is a resistor that changes bias range. That's it, a single resistor.

In a small single ended amp, you bet your ass that a power tube change is going to signficantly alter your tone.
Last edited by al112987 at Nov 19, 2009,
#12
glpoon your really going to need some sort of schematic for us to look at.

Is it possible to put an el34 in a 6l6 amp, sometimes. You would at minimum have to rebias the amp. Your big issue is going to be the power supply. El34 heater current is 2x what the 6l6 uses. Im going to imagine your amp like many is built with just enough power to function in its stock configuration. So the stock power trans may or may not have what it takes to push an el34.
#13
If you take a look at some of the ts threads it might help explain what he is trying to do. I think schematics are a great start.


Edit: I think al112987 is correct (for most all amps)


Double Edit: .....v...I think he is still maybe a helpful dude. People don't have to buy his JJs. Just sayin'
Last edited by 311ZOSOVHJH at Nov 19, 2009,
#14
Quote by Jesstaa
Ask a trusted tech, I only see 1 power tube in that picture, so I'm guessing it's self biasing. Some amps (Self biasing or not) can switch between EL34 and 6L6 with no problems, others might require a resistor changed.

If you don't know of a trusted tech, ask Bob from eurotubes, he's a helpful dude and wont just try and palm off JJ's on you.

Considering JJ is all Bob sells, I think that would be exactly what he would do.
#15
Quote by forsaknazrael
Considering JJ is all Bob sells, I think that would be exactly what he would do.


^This!

Great company, great guy.
But yes, you will only be getting JJ's!

TS: Depends on the amp. Got a schematic?
I can honestly say I've never heard of this amp before.

There's no question it is possible, there is less difference than one might suspect in running the tubes. No "circuit board" modifying will be necessary beyond a resistor or two.

It is, however, usually more drastic than just re-biasing.

More importantly, tell us why. What are you looking for?
Difference in tone?
More/less headroom?
Change in break-up?
Or just curious? (just as valid a reason!)
#16
Quote by al112987
do you even know what change you have to make on the circuit board? or what is required to switch to EL34s?

The only board change you need is a resistor that changes bias range. That's it, a single resistor.

In a small single ended amp, you bet your ass that a power tube change is going to signficantly alter your tone.



I suppose screen resistors can be just left alone then?

Then it strikes me, I suppose your argument would be coming from the fact that you're talking about the "single small ended amp" which is what our OP seems to be referring, and I'm talking about larger amps.

Make no mistakes, you are not talking to an idiot.
Tastes like chicken, if chicken was a candy.
Last edited by ConfederateAxe at Nov 20, 2009,
#17
Quote by ConfederateAxe
I suppose screen resistors can be just left alone then?

Then it strikes me, I suppose your argument would be coming from the fact that you're talking about the "single small ended amp" which is what our OP seems to be referring, and I'm talking about larger amps.

No, he was talking about small single ended amps, not 'single small ended amps.'

And why would you attack what he said, then caveat it with 'I'm only right if you ignore the single most important piece of information here...'

Jackass.
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Quote by Raijouta
Unless its electronic drums.

BURN THE WITCH!!!!!
#18
Quote by tubetime86
No, he was talking about small single ended amps, not 'single small ended amps.'

And why would you attack what he said, then caveat it with 'I'm only right if you ignore the single most important piece of information here...'

Jackass.



An unintentional swapping of words. I know what he meant, and I know what I meant. Jackass.
Tastes like chicken, if chicken was a candy.
#19
Quote by ConfederateAxe
An unintentional swapping of words. I know what he meant, and I know what I meant. Jackass.

I know that's why I put the 'haha' thing after it. I was calling you a jackass because you basically said 'You're wrong in most cases other than this one...'

Jackass.

(That one was just for lulz. )
Quote by Cathbard
Quote by Raijouta
Unless its electronic drums.

BURN THE WITCH!!!!!
#20
Quote by ConfederateAxe
Most of the time on what amp? I certainly couldn't just slap EL34s in my Peavey.


Just for the record you can flip a switch and slap a set of EL34s in a Peavey XXX.
#22
Quote by WtrPlyr
I find it odd the OP wants to replace his 6L6 with EL34s, but still he has to ask what the difference is between the two...


I suspect he should fit in very well here on UG.