Feel free to ask Myles

[rsf1977]

Hey Myles so I wanted to know what rating of 12AX7s to put in my Dual Rect. for V1 and V2 if I were to buy them from groove tubes (low, med, High) and if I were to get SAG tubes what should I get. Also what tuge is good to use in the Phase Inverter.

 

Just a reminder I play High gain Metal with a tight bottom and I just ordered the GE6L6s if that matters in your recommendation, thanks.

[myles_rose]

Originally posted by rsf1977:

Hey Myles so I wanted to know what rating of 12AX7s to put in my Dual Rect. for V1 and V2 if I were to buy them from groove tubes (low, med, High) and if I were to get SAG tubes what should I get. Also what tuge is good to use in the Phase Inverter.

 

Just a reminder I play High gain Metal with a tight bottom and I just ordered the GE6L6s if that matters in your recommendation, thanks.

I use GT-12AX7R3's in Mesa Dual and Triple rectifiers, with a HIGH/Fast rating, but on the "low" side of the HIGH scale. The Recto's have high gain already, and too HIGH of a HIGH will limit the range of volume controls as it will get too much distorion too fast, and turn it all to gribble-hash.

 

For my own clients, I use a V1 of 100-125.

 

For the phase inverter, I use any of the 12AX7's as they are not part of the tone generation stage and are chosen for current drive and rise time. There is normally not a rating pull down over on the GT website for this tube.

 

You can see them both at:

 

http://www.groovetubes.com/product.cfm?Product_ID=1723

 

and

 

http://www.groovetubes.com/product.cfm?Product_ID=1733

 

Some folks like the longer plate R2 but about 70% of my clients prefer the R3 as do I.

 

Regards,

[rsf1977]

Is there a certain preamp tube that deals with the clean channel only, or do both channels use all the preamp tubes equally?

 

Also do you think NOS tubes are a good idea for the Dual Rec I'm considering getting 2 Mullard ECC83 for V1 and V2?

[myles_rose]

Originally posted by rsf1977:

Is there a certain preamp tube that deals with the clean channel only, or do both channels use all the preamp tubes equally?

 

Also do you think NOS tubes are a good idea for the Dual Rec I'm considering getting 2 Mullard ECC83 for V1 and V2?

Most circuits, and I will say "most" but not all, use V1 as the first gain stage (or in a blackface fender, V1 for the Normal channel and V2 as the first gain stage for the vibrato channel), and the first stage "usually" will feed additional gain stages in a multi channel amp.

 

Regards,

[Dave da Dude]

I've finally got my 1993 Randall Pro 1000 II amp.

 

I checked the tubes before I turned it on (it's warming up now).

 

The Pre-Amp tubes are "Randall" brand (I assume original 1993) 12AX7A. Can I do better?

 

The amp has a bias switch for EL34 or 6L6.

 

Right now it has Sylvania (looks like )626 ABU tubes in it. Can I do better than those?

 

The EL34's are Chinese tubes. What's your best suggestion for their replacement?

 

I know this is a lot and very general, I'm just looking for some place to get started.

[myles_rose]

Originally posted by Dave th Dude:

I've finally got my 1993 Randall Pro 1000 II amp.

 

I checked the tubes before I turned it on (it's warming up now).

 

The Pre-Amp tubes are "Randall" brand (I assume original 1993) 12AX7A. Can I do better?

 

The amp has a bias switch for EL34 or 6L6.

 

Right now it has Sylvania (looks like )626 ABU tubes in it. Can I do better than those?

 

The EL34's are Chinese tubes. What's your best suggestion for their replacement?

 

I know this is a lot and very general, I'm just looking for some place to get started.

Dave,

 

If all the tubes are "original" and 1993, it may be time to replace all of them.

 

Without looking at the tubes, its hard to say what they are from my point of reference.

 

There is no such thing as "Randall" tubes, their name was silkscreened on them at some point, so their origin is unknown.

 

The Chinese EL-34's can be improved upon from tube from just about any source. I am surprised that they have held up this long. That is one indication that the amp was not played hard too often.

 

I would have the amp gone over, the bias checked, pots cleaned, noise floor checked to verify the condition of the filter caps, and then replace those power tubes and their associated phase inverter for a start. Make sure the bias is checked, don't rely on the switch to do this properly.

 

Regards,

[throb13]

Hi Myles,

I sent you an e-mail last week at the Groove tubes tech address. I don't know if you responded to it yet because the e-mail address I gave you is experiencing problems with incoming mail. I haven't received any outside e-mails for days at that address. So, I figured I better do this the right way and send it here. The main text of the e-mail was this: I own a Marshall JCM 2000 TSL100 head. The Groove Tubes SAG kits seem to have only 3 pre amp tubes. My Marshall has 4. Will you eventually be selling kits for JCM 2000's? If not, then what would you recommend for each input (rating wise) for that elusive "brown sound? " I know...you probably get a zillion people who want to capture EVH in a tube. Well, make me a zillion and one then.

Also, what GT EL 34 power tube rating would be best?

Thanks for taking the time to read this,

Pasquale

[myles_rose]

Originally posted by throb13:

Hi Myles,

I sent you an e-mail last week at the Groove tubes tech address. I don't know if you responded to it yet because the e-mail address I gave you is experiencing problems with incoming mail. I haven't received any outside e-mails for days at that address. So, I figured I better do this the right way and send it here. The main text of the e-mail was this: I own a Marshall JCM 2000 TSL100 head. The Groove Tubes SAG kits seem to have only 3 pre amp tubes. My Marshall has 4. Will you eventually be selling kits for JCM 2000's? If not, then what would you recommend for each input (rating wise) for that elusive "brown sound? " I know...you probably get a zillion people who want to capture EVH in a tube. Well, make me a zillion and one then.

Also, what GT EL 34 power tube rating would be best?

Thanks for taking the time to read this,

Pasquale

I don't have any outstanding mail at GT that I have not answered, and I did answer this one.

 

I will send it again, just send your email address back to me at techsupport@groovetubes.com so I can look for my response from there.

 

Myles

[DrMr]

Hello!

 

I have a problem with my low sound.I play down to B on 6-string guitar(Ibanez RG550LTD with EMG-81) and I think that distortion doesn't sound soo deep

.Some people say that you need special amp to generate sounds like 7-string guitar.Should I buy new amp, new cabinet,new tubes or 7-string guitar????!!!

Setup:

CARVIN X-100B TUBE

Power tubes: National Electronics 6CA7/EL 34

Preamb tubes:EuD or Dub(idon'tknow??) ECC83/12AX7A

Cabinet/Box:Marshall 4x12,4x30W, very old box(Is this 8 or 16ohms????)

 

Thanx

 

Tomaz

[myles_rose]

Originally posted by DrMr:

Hello!

 

I have a problem with my low sound.I play down to B on 6-string guitar(Ibanez RG550LTD with EMG-81) and I think that distortion doesn't sound soo deep

.Some people say that you need special amp to generate sounds like 7-string guitar.Should I buy new amp, new cabinet,new tubes or 7-string guitar????!!!

Setup:

CARVIN X-100B TUBE

Power tubes: National Electronics 6CA7/EL 34

Preamb tubes:EuD or Dub(idon'tknow??) ECC83/12AX7A

Cabinet/Box:Marshall 4x12,4x30W, very old box(Is this 8 or 16ohms????)

 

Thanx

 

Tomaz

Tomaz,

 

I don't think you need a special amp, you just need an amp that is set up right most of the time. You amp has a nice power supply, and the National 6CA7's are good tubes, with more vacuum than a EL-34 from the other side of the pond.

 

First I would have the bias checked. If the tubes are worn or out of match, that would cause all sorts of problems.

 

If those look okay, then have somebody look at your phase inverter that drives the output section. Chances are this is not a balanced valve, and you may want to procure a balanced valve or as we call it on this side of the pond, a matched phase inverter.

 

http://www.groovetubes.com/product.cfm?Product_ID=1723

 

Regards,

 

Myles

[dondottcomm]

Hey Myles,I've got a 25/50 Jubilee Marshall 1/2 stack..And when Im playin the sound drops it gets real soft{volume} I know the chord is good ect. What is goin on with it..is it a pre tube or power tube or something like that??Thanks in advance!

[truls]

I've read with great interest your web page about blueprinting amplifiers, and I have some questions for you, mainly regarding Marshall Valvestate amps.

 

I use my VS100 for mostly playing rythm metal stuff, and I think my ideal sound can be described as medium/high gain, well defined, thight midrange, scoped off high and moderate lows. To make this possible I use a TC.Electronics parametric equalizer, and the amplified signal is led to a single Vintage 30 in a custom cabinet. For studio applications I run the amp 100% dry into the mix, then adding desired effects afterwards. The eq on the amp is set flat.

 

Is it possible to by-pass and/or disassemble the eq-pots on the amp??

 

What happen if I switch the capacitors in the output section to some of a higher or lower capacitance??

 

Would it add much a difference just changing the capacitors to a high-end metal film type??

 

What pre-amp tube would you recommend for this application??

 

Any other suggestions regarding modifications??

 

Any replies would be much appreciated

 

Regards

 

Truls Herland

[myles_rose]

Originally posted by dondottcomm:

Hey Myles,I've got a 25/50 Jubilee Marshall 1/2 stack..And when Im playin the sound drops it gets real soft{volume} I know the chord is good ect. What is goin on with it..is it a pre tube or power tube or something like that??Thanks in advance!

dondottcomm,

 

First exchange V1 and some other tube, and see if that changes anything. If it does, it is a bad preamp tube. If not, try V2, etc.

 

This sounds more like a power tube problem though, how old are the output tubes?

 

Myles

[myles_rose]

Originally posted by truls:

I've read with great interest your web page about blueprinting amplifiers, and I have some questions for you, mainly regarding Marshall Valvestate amps.

 

I use my VS100 for mostly playing rythm metal stuff, and I think my ideal sound can be described as medium/high gain, well defined, thight midrange, scoped off high and moderate lows. To make this possible I use a TC.Electronics parametric equalizer, and the amplified signal is led to a single Vintage 30 in a custom cabinet. For studio applications I run the amp 100% dry into the mix, then adding desired effects afterwards. The eq on the amp is set flat.

 

Is it possible to by-pass and/or disassemble the eq-pots on the amp??

 

What happen if I switch the capacitors in the output section to some of a higher or lower capacitance??

 

Would it add much a difference just changing the capacitors to a high-end metal film type??

 

What pre-amp tube would you recommend for this application??

 

Any other suggestions regarding modifications??

 

Any replies would be much appreciated

 

Regards

 

Truls Herland

Truls,

 

Anything is possible when it comes to mods. THE MAN for mods is Trace over at Voodoo Amps.

 

It sounds like the easier thing to do than radically mod an amp that has a solid state output section would be to purchase another amp that has the sound you are after.

 

Regards,

[dondottcomm]

They are the original tubes I bet..I got this used in mint shape from a studio..I will give it a shot ..Thank you sir!

[Dave da Dude]

Myles, more on the Randall Amp (or any amp, I guess).

 

I figure the two power amp tubes (6L6 or EL34) are one for clean channel, one for dirty channel. How do I know which one is which?

 

There are four pre amp tubes. What are they for? Should I use different types (i.e clean and dirty channels)?

 

Sorry for the VERY basic questions, but I'm still a neophite at guitar ELECTRONICS.

 

Thanks, Dave Phoenix.

[WDC]

Miles,

 

Great info. I've been geeking in this forum and on your site. One day I hope to acquire a thimbleful of your knowledge.

 

Here is my question. I am the owner of a Soldano Supercharger G.T.O. and love the tone. The only thing disappointing about the pedal is the noise when engaged and not playing. Is there anything I can do to alleviate this? From what I've read, this symptom seems to be inherent with all the pedals. I've called Soldano and was told that because this is a tube pedal, the noise is inherited. I guess I'm just waiting for someone to mod this fine pedal to take away some of the noise. Any suggestions?

 

Sorry that if I'm posting this in the wrong area, but as this pedal runs plate voltage and has 2 12ax7 tubes, I figured I would ask here. Can this pedal be blueprinted?

 

Thanks in advance,

 

World Driving Champion

[hechtdavid]

Hi Myles,

 

Evil one needs help... I just got a new set of GT 6L6GE's for my 1999 Evil Twin and it now won't bias properly. (I think it may have had this problem before the new tubes.) To get the balance to read correctly, I have to set the bias up around 80mV (too hot for me) - and then the balance adjustment pot is set at the maximum (counterclockwise) range. Any ideas? Time to take it in for a checkup?

[myles_rose]

Originally posted by dondottcomm:

Hey Myles,I've got a 25/50 Jubilee Marshall 1/2 stack..And when Im playin the sound drops it gets real soft{volume} I know the chord is good ect. What is goin on with it..is it a pre tube or power tube or something like that??Thanks in advance!

dondottcomm ....

 

it is probably power tubes, but a quick way to check is to swap your preamp tubes around a bit and see if this makes a change.

 

Myles

[myles_rose]

Originally posted by Dave th Dude:

Myles, more on the Randall Amp (or any amp, I guess).

 

I figure the two power amp tubes (6L6 or EL34) are one for clean channel, one for dirty channel. How do I know which one is which?

 

There are four pre amp tubes. What are they for? Should I use different types (i.e clean and dirty channels)?

 

Sorry for the VERY basic questions, but I'm still a neophite at guitar ELECTRONICS.

 

Thanks, Dave Phoenix.

Dave,

 

The power tubes always work together ... clean or dirty.

 

The preamp tubes are generally for your first and second gain stages, and the last preamp tube is the phase inverter that drives the output tubes.

 

Other preamp tubes are for effects loops, reverb drivers, and vibrato drivers.

 

Myles

[myles_rose]

Originally posted by WDC:

Miles,

 

Great info. I've been geeking in this forum and on your site. One day I hope to acquire a thimbleful of your knowledge.

 

Here is my question. I am the owner of a Soldano Supercharger G.T.O. and love the tone. The only thing disappointing about the pedal is the noise when engaged and not playing. Is there anything I can do to alleviate this? From what I've read, this symptom seems to be inherent with all the pedals. I've called Soldano and was told that because this is a tube pedal, the noise is inherited. I guess I'm just waiting for someone to mod this fine pedal to take away some of the noise. Any suggestions?

 

Sorry that if I'm posting this in the wrong area, but as this pedal runs plate voltage and has 2 12ax7 tubes, I figured I would ask here. Can this pedal be blueprinted?

 

Thanks in advance,

 

World Driving Champion

WDC ....

 

Pedals can be a noise issue. A lot of folks resort to using noise gates. If I could test the tubes in the pedal and see what they were doing, then perhaps we could replace them with ones that are less noisy and have a lower noise floor.

 

Other than that, its either live with the noise, or the noise gate idea.

 

Sorry,

 

Myles

[myles_rose]

Originally posted by hechtdavid:

Hi Myles,

 

Evil one needs help... I just got a new set of GT 6L6GE's for my 1999 Evil Twin and it now won't bias properly. (I think it may have had this problem before the new tubes.) To get the balance to read correctly, I have to set the bias up around 80mV (too hot for me) - and then the balance adjustment pot is set at the maximum (counterclockwise) range. Any ideas? Time to take it in for a checkup?

80mA is WAY too high. Did you check before the install of the new tubes to see what it was reading? I would think it was too high already.

 

The Twin is a four output tube variant of the Pro and Concert. On the two tube variants, 30mA is the Fender spec. I would think that 60mA would be your spec, as your bias/balance looks at two of the tubes rather than just one, as the B+ voltage on this amp is the same as the two tube output sections.

 

If you know somebody with a bias tool, bias probe, bias king, etc., look at just a single tube and see if it is around 30mA.

 

Make sure your meter is on the left and center test points, red on the left (facing the rear of the amp) and black lead in the center. Then for balance, move the left red probe to the right, leaving the black probe in the center and adjust for 0mA to balance.

 

Who told you to set this at 80mA? This is pretty wrong. Set it to 60mA, or 0.6 on your meter.

 

Regards,

 

Myles

[hechtdavid]

Hi Myles,

 

I guess I didn't phase my question very well. Sorry about that.. I CAN set the bias on my evil twin at a lower setting, but at that lower bias setting, I can NOT set the balance properly. The only way to set the balance to 0 is to raise the bias setting to 77mV or more; the balance will be set to 0 - but only at the furthest conterclockwise postion on the pot. BTW, I am using a cheap radio shack DVM, and its worked fine in the past. I'm sure I'm checking bias and balance properly on this amp.

 

Thanks again for all your generous wisdom.

 

David

[Dave da Dude]

QUOTE

 

Myles, more on the Randall Amp (or any amp, I guess).

 

I figure the two power amp tubes (6L6 or EL34) are one for clean channel, one for dirty channel. How do I know which one is which?

 

There are four pre amp tubes. What are they for? Should I use different types (i.e clean and dirty channels)?

 

Sorry for the VERY basic questions, but I'm still a neophite at guitar ELECTRONICS.

 

Thanks, Dave Phoenix.

--------------------------------------------------------------------------------

 

QUOTE

 

Dave,

 

The power tubes always work together ... clean or dirty.

 

The preamp tubes are generally for your first and second gain stages, and the last preamp tube is the phase inverter that drives the output tubes.

 

Other preamp tubes are for effects loops, reverb drivers, and vibrato drivers.

 

Myles

 

Myles,

 

Is there a way to KNOW which tube is first gain, second gain, phase inverter, etc.? Do all tubes need to be of equal quality and / or output?

 

Lastly (I, and I imagine, you, hope), I have four tubes, and one is first gain, one second gain, one phase inverter and I have BOTH reverb and effects loop what's going on? That would be five tubes!

 

I'm just trying to understand if I need to spend the same (high) amount of money on all four tubes. I thought I remembered you saying someplace in this ongoing posting, that a certain tube or tubes was not as important to be high quality.

 

Thanks for any help, Dave.

[myles_rose]

Originally posted by hechtdavid:

Hi Myles,

 

I guess I didn't phase my question very well. Sorry about that.. I CAN set the bias on my evil twin at a lower setting, but at that lower bias setting, I can NOT set the balance properly. The only way to set the balance to 0 is to raise the bias setting to 77mV or more; the balance will be set to 0 - but only at the furthest conterclockwise postion on the pot. BTW, I am using a cheap radio shack DVM, and its worked fine in the past. I'm sure I'm checking bias and balance properly on this amp.

 

Thanks again for all your generous wisdom.

 

David

Dave,

 

It sounds like you are doing things properly, and the cheap Radio Shack DVM is not the problem, as those meters work just fine for ohms, volts, current, etc. If the meter makes numbers that change on its display, it is fine and dandy.

 

Try swapping the tubes around, as to try to isolate a possible bad tube. Shipping damage or other physical damage in not all that uncommon, and one tube may be way out of wack. If you can put your old tubes back in and bias properly, that right there rules out your dvm, amp, procedure, and everything else.

 

What area are your from? If you are close to Los Angeles, I would be more than happy to look at this for you at no charge.

 

Myles

[myles_rose]

Originally posted by Dave th Dude:

QUOTE

 

Myles, more on the Randall Amp (or any amp, I guess).

 

I figure the two power amp tubes (6L6 or EL34) are one for clean channel, one for dirty channel. How do I know which one is which?

 

There are four pre amp tubes. What are they for? Should I use different types (i.e clean and dirty channels)?

 

Sorry for the VERY basic questions, but I'm still a neophite at guitar ELECTRONICS.

 

Thanks, Dave Phoenix.

--------------------------------------------------------------------------------

 

QUOTE

 

Dave,

 

The power tubes always work together ... clean or dirty.

 

The preamp tubes are generally for your first and second gain stages, and the last preamp tube is the phase inverter that drives the output tubes.

 

Other preamp tubes are for effects loops, reverb drivers, and vibrato drivers.

 

Myles

 

Myles,

 

Is there a way to KNOW which tube is first gain, second gain, phase inverter, etc.? Do all tubes need to be of equal quality and / or output?

 

Lastly (I, and I imagine, you, hope), I have four tubes, and one is first gain, one second gain, one phase inverter and I have BOTH reverb and effects loop what's going on? That would be five tubes!

 

I'm just trying to understand if I need to spend the same (high) amount of money on all four tubes. I thought I remembered you saying someplace in this ongoing posting, that a certain tube or tubes was not as important to be high quality.

 

Thanks for any help, Dave.

Dave,

 

On less expensive amps, the reverb or effects loop does not need to be tube driven, it is transistor driven such as the reverb on the Fender Hot Rod series amps.

 

As far as what tube does what, there is a lot of basic background that you may want to start learning, rather than just get the answers to disjointed parts of a particular area. I would suggest a good tube book. There are a number of them available from: www.tubesandmore.com

 

Myles

[Dave da Dude]

Myles,

 

I went to www.tubesandmore.com as you recommended and they have QUITE a few books on tube amps.

 

Are there any that you can recommend for a neophyte like myself that wants to understand how the amp works and what type of tubes to put where?

 

Dave

[myles_rose]

Originally posted by Dave th Dude:

Myles,

 

I went to www.tubesandmore.com as you recommended and they have QUITE a few books on tube amps.

 

Are there any that you can recommend for a neophyte like myself that wants to understand how the amp works and what type of tubes to put where?

 

Dave

The "bible" from most folks point of view, that covers amps, history, theory, mods, has prints, etc is the GT book:

 

http://www.groovetubes.com/product.cfm?Product_ID=1188

 

Which I think they also stock.

 

Myles

[hechtdavid]

Originally posted by myles111:

Originally posted by hechtdavid:

Hi Myles,

 

I guess I didn't phase my question very well. Sorry about that.. I CAN set the bias on my evil twin at a lower setting, but at that lower bias setting, I can NOT set the balance properly. The only way to set the balance to 0 is to raise the bias setting to 77mV or more; the balance will be set to 0 - but only at the furthest conterclockwise postion on the pot. BTW, I am using a cheap radio shack DVM, and its worked fine in the past. I'm sure I'm checking bias and balance properly on this amp.

 

Thanks again for all your generous wisdom.

 

David

Dave,

 

It sounds like you are doing things properly, and the cheap Radio Shack DVM is not the problem, as those meters work just fine for ohms, volts, current, etc. If the meter makes numbers that change on its display, it is fine and dandy.

 

Try swapping the tubes around, as to try to isolate a possible bad tube. Shipping damage or other physical damage in not all that uncommon, and one tube may be way out of wack. If you can put your old tubes back in and bias properly, that right there rules out your dvm, amp, procedure, and everything else.

 

What area are your from? If you are close to Los Angeles, I would be more than happy to look at this for you at no charge.

 

Myles

Damn Myles,

 

You are a generous guy! I wish I was close to LA, but Madison, WI. is a bit far to lug an Evil Twin. If you ever get out this way, I'd like to buy you a few of your favorite libations. But I digress... enough about how great you are. You are, and I'll leave it at that.

 

The ET: It exhibits the same problems after swapping tubes back to the old Svets, so I don't think its a tube problem. The amp works, but I'm reluctant to use it right now because of the hot bias I have to run just to get the balance to 0. I noticed when I first removed the Svets that the bases were discolored from the heat. I'd rather not run the GT 6L6GE's and burn them up too quickly since they're a bit on the pricey side. I'm assuming its time to take it in to the local amp tech. Any hypotheses?

 

Thanks again

 

David

[myles_rose]

Originally posted by hechtdavid:

Originally posted by myles111:

Originally posted by hechtdavid:

Hi Myles,

 

I guess I didn't phase my question very well. Sorry about that.. I CAN set the bias on my evil twin at a lower setting, but at that lower bias setting, I can NOT set the balance properly. The only way to set the balance to 0 is to raise the bias setting to 77mV or more; the balance will be set to 0 - but only at the furthest conterclockwise postion on the pot. BTW, I am using a cheap radio shack DVM, and its worked fine in the past. I'm sure I'm checking bias and balance properly on this amp.

 

Thanks again for all your generous wisdom.

 

David

Dave,

 

It sounds like you are doing things properly, and the cheap Radio Shack DVM is not the problem, as those meters work just fine for ohms, volts, current, etc. If the meter makes numbers that change on its display, it is fine and dandy.

 

Try swapping the tubes around, as to try to isolate a possible bad tube. Shipping damage or other physical damage in not all that uncommon, and one tube may be way out of wack. If you can put your old tubes back in and bias properly, that right there rules out your dvm, amp, procedure, and everything else.

 

What area are your from? If you are close to Los Angeles, I would be more than happy to look at this for you at no charge.

 

Myles

Damn Myles,

 

You are a generous guy! I wish I was close to LA, but Madison, WI. is a bit far to lug an Evil Twin. If you ever get out this way, I'd like to buy you a few of your favorite libations. But I digress... enough about how great you are. You are, and I'll leave it at that.

 

The ET: It exhibits the same problems after swapping tubes back to the old Svets, so I don't think its a tube problem. The amp works, but I'm reluctant to use it right now because of the hot bias I have to run just to get the balance to 0. I noticed when I first removed the Svets that the bases were discolored from the heat. I'd rather not run the GT 6L6GE's and burn them up too quickly since they're a bit on the pricey side. I'm assuming its time to take it in to the local amp tech. Any hypotheses?

 

Thanks again

 

David

David ....

 

Well, if the same problem shows up with the svets, then its something in the amp.

 

Perhaps a resistor failed that in in the bias balance circuit. It could be a number of things, but its an area easily trouble shot.

 

Get it over to Fender shop, as these amps have a pretty long warranty.

 

Drop me a line to keep me in the loop if you want me to talk to your tech.

 

Myles