#1
My buddy is wondering if he were to switch the EL34s that were in there to 6L6s, would he have to do anything else besides flip the amp bias switch on the back? Just wondering because he doesnt want to mess anything up.

Thanks.
(Gear in profile)

Yes I do like metal, no I'm not a close minded idiot.
#4
Yea thats what we were figuring , he just wanted to make sure.
Thanks for the reply though.

Anyone else?
(Gear in profile)

Yes I do like metal, no I'm not a close minded idiot.
#5
The amp is self biasing for EL34/6L6 tubes.
Quote by zgr0826
My culture is worthless and absolutely inferior to the almighty Leaf.


Quote by JustRooster
I incurred the wrath of the Association of White Knights. Specifically the Parent's Basement branch of service.
#7
Quote by H4T3BR33D3R
The amp is self biasing for EL34/6L6 tubes.


What exactly does this mean, i emailed my local guitar shop and they said

the GH100L is a fixed bias amp, you just need to make sure that you put matched pairs in the output stage

Then i e-mailed Eurotubes and he said

Your local guitar shop does not know anything about amps. They told you its fixed bias and it is not... It is an adjustable bias amps just as we had explained in an earlier email. You need to install and bias the amp for new tubes

Help me please :P
Ibanez PGM301 signed by Paul Gilbert
Ibanez PGM 500
Ibanez Fireman custom
Saving for a GH100L/VH100R
Orange PPC212 2X12
#9
Quote by sharpant
What exactly does this mean, i emailed my local guitar shop and they said

the GH100L is a fixed bias amp, you just need to make sure that you put matched pairs in the output stage

Then i e-mailed Eurotubes and he said

Your local guitar shop does not know anything about amps. They told you its fixed bias and it is not... It is an adjustable bias amps just as we had explained in an earlier email. You need to install and bias the amp for new tubes

Help me please :P


It's what I said it is. Self Biasing. The amp does the bias work for you. You just plug and go.

EDIT: Apparantly not.

^ Do you? I used to just swap them out with my VH100R?
Quote by zgr0826
My culture is worthless and absolutely inferior to the almighty Leaf.


Quote by JustRooster
I incurred the wrath of the Association of White Knights. Specifically the Parent's Basement branch of service.
#10
Quote by H4T3BR33D3R
It's what I said it is. Self Biasing. The amp does the bias work for you. You just plug and go.

EDIT: Apparantly not.

^ Do you? I used to just swap them out with my VH100R?

The switch just gets you in the range of the right voltage and you have to bias using the trim pot inside to get it to a safer/correct voltage.
#11
haha pwned! cheers anyway looks like you learnt something new about your amp
Ibanez PGM301 signed by Paul Gilbert
Ibanez PGM 500
Ibanez Fireman custom
Saving for a GH100L/VH100R
Orange PPC212 2X12
#12
Quote by SG thrasher
The switch just gets you in the range of the right voltage and you have to bias using the trim pot inside to get it to a safer/correct voltage.


Oh, I see.


TS, listen to this guy. He knows his stuff.
Quote by zgr0826
My culture is worthless and absolutely inferior to the almighty Leaf.


Quote by JustRooster
I incurred the wrath of the Association of White Knights. Specifically the Parent's Basement branch of service.
#14
Sg thrasher, I'm about to ask you a huge favor so get ready :P I've got these coming in the next 2/3 days from Eurotubes

JJ EL34 High Gain Option Kit

Looking for the most aggressive and punchy EL34 sound with all the gain you can get? This kit comes with a matched quad of the JJ E34L's and four hand picked high gain ECC83S's with one of them being balanced for the phase inverter in V4.

Multimeter
Bios Probe

If you've got the time would you consider writing me a short list of instructions/ big dos and donts with retubing/biasing the GH100L
Ibanez PGM301 signed by Paul Gilbert
Ibanez PGM 500
Ibanez Fireman custom
Saving for a GH100L/VH100R
Orange PPC212 2X12
#15
Quote by sharpant
What exactly does this mean, i emailed my local guitar shop and they said

the GH100L is a fixed bias amp, you just need to make sure that you put matched pairs in the output stage

Then i e-mailed Eurotubes and he said

Your local guitar shop does not know anything about amps. They told you its fixed bias and it is not... It is an adjustable bias amps just as we had explained in an earlier email. You need to install and bias the amp for new tubes

Help me please :P


Ok, there seems to be a misunderstanding here.

Fixed bias is the same thing as adjustable bias, when people say self biasing, it means cathode bias. For an amp with a fixed bias circuit, yes you do need to bias for different tubes.
Last edited by al112987 at Oct 11, 2008,
#16
Your amp doesn't have a bias pot. It doesn't seem like you're quite ready to do that kind of thing yet, so I'd have a tech add one for you. It will be cheap and he may even do it while you wait since it's a simple mod. Since you have bias probes it makes sense to ask for a bias pot on the chassis of the amp in the back so you don't have to open it up to bias.
Once that's done, you'll be able to bias it yourself quite easily.
#17
There is a tutorial video on eurotubes on how to do it, plus everyone keeps telling me to go see a tech, where are these techs!? Live in SE London. Do you need a bias pot to pick up a reading, if so is amp impossible to bias at the moment?
Ibanez PGM301 signed by Paul Gilbert
Ibanez PGM 500
Ibanez Fireman custom
Saving for a GH100L/VH100R
Orange PPC212 2X12
#18
You don't need a bias pot to read the bias. You need it to change the bias.
Techs can be found in, or contacted via most guitar shops.
#19
Quote by sharpant



Then i e-mailed Eurotubes and he said

Your local guitar shop does not know anything about amps. They told you its fixed bias and it is not... It is an adjustable bias amps just as we had explained in an earlier email. You need to install and bias the amp for new tubes

Help me please :P


Looks like the guy in Eurotubes doesn't know what he's talking about. I thought these guys were supposed to know what they were about?
#20
what they said is correct ?
Ibanez PGM301 signed by Paul Gilbert
Ibanez PGM 500
Ibanez Fireman custom
Saving for a GH100L/VH100R
Orange PPC212 2X12
#21
I had one and you have to bias it, the switch is a waste of time and 99% of the time will be way out. Sorry to say man it isnt fixed, there is a trim pot and i have adjusted one before.