rebais during winter?

DragonSarc · 12-22-2008, 05:14 AM

I replaced all my tubes from eurotubes this summer and only been played the TSL 100 amp no more than 20 hrs off and on with my attenuator no more than 4 hrs per play with vpr on and sometimes off, it was biased at 80 , now my amps volume decreased i checked the bias again and my multi meter is saying 30mv? ive switched the power tubes and pre amp tubes around and still the same, do you have to rebais the amp during winter cuz its colder? the bais shouldnt change once its set right unless the tube goes bad right?

Brett Blackmore · 12-22-2008, 06:33 AM

Hi,

no. Winter / summer is irrelevant (sure a rehearsal room will be colder than at home but you know what I mean...). You have a tube down. Either it is not seated right or faulty.

Cheers Brett

big dooley · 12-22-2008, 09:00 AM

JCM2000's have the irritating tendency to drift their bias, unfortunatly...
i think it's a design-flaw which was more or less corrected in the JVM series, where the same biasing-system is moved to the inside of the chassis
i keep checking the bias regularly, because it tends to drift too

jcmjmp · 12-22-2008, 09:39 AM

Quote:

Originally Posted by big dooley

JCM2000's have the irritating tendency to drift their bias, unfortunatly...
i think it's a design-flaw which was more or less corrected in the JVM series, where the same biasing-system is moved to the inside of the chassis
i keep checking the bias regularly, because it tends to drift too

JCM2000's in general or just the TSL line?
My DSL is checked over every 6-9 months and I've never seen bias drift that was more than 1-2 mv.

Maybe the OP's tubes are bad, causing the drift. When you tap the amp, does it shift bias?

The TSLs do have a known problem with the bias resistors and that can be fixed failry easily but that's only when the amp gets hot.
The Marshall TSL122-JCM2000 Repair/Mods Page

DragonSarc · 12-22-2008, 04:34 PM

wow bad tubes already? it took the orig tubes to die about 4yrs how come the new ones died in few month?

steelhorse · 12-22-2008, 05:06 PM

If they're a month old they'll be covered by warranty if you bought them from a reputable dealer. They're just like anything else, sometimes a bad one slips through.

Where'd you get them if you don't mind me asking?

dcooper830 · 12-22-2008, 05:34 PM

I put a set of JJs from Eurotubes in one of my DSL 100s once. I kept having to set the bias cause it kept going way out.

Finally I got tired of re-biasing and just kept using the amp until it started giving me high pitched screechy sounds intermittently. I didn't know what the problem was..... but when I checked the bias I was getting a ZERO reading on one side.

I took it in for repair and the guy said a solder joint had gone out on the bias resistor or screen grid resistor....... I can't remember.

In any event.. He repaired it and put in a new set of Svetlana tubes. The bias has been holding steady ever since.

I think it was all because of bad JJs from Eurotubes.

However...... I still like Bob and have always had good service from him.

DragonSarc · 12-22-2008, 06:37 PM

Quote:

Originally Posted by steelhorse

If they're a month old they'll be covered by warranty if you bought them from a reputable dealer. They're just like anything else, sometimes a bad one slips through.

Where'd you get them if you don't mind me asking?

I got them a while back maybe 5-6mo ago from eurotubes - i tried playing with the bias pots and it only goes to 65 mV on the left and 70 on the right then i still have the old orig tubes and switch those out and the bias goes crazy on the right side if i go pass 75 mV - is there any way to tell which one is bad? or i just need to replace the whole set? sux me and my cuz was going to jam this holiday get together.

steelhorse · 12-22-2008, 06:48 PM

I suggest calling Euro Tubes right away and tell them what's going on. They should be able to help.

It may be more than the tubes if it's reacting with the Euro set and the old set as badly as it is. That doesn't sound like a tube issue but perhaps a resistor issue. Like I said give them a call.

DragonSarc · 12-22-2008, 07:03 PM

thanks steel will do hopefully it wont be costly

big dooley · 12-22-2008, 08:37 PM

well. what i would like to know...
do non-JCM2000 amps have the same bias-drift problems with JJ's?
i only read stories of DSL's and TSL's with drifting problems, which in my opion cannot be blamed on the tubes if 800's, 900's, mk2's etc etc don't have those problems...

this evening i found out the bias in my DSL100 was drifted again with the KT77's
oddly enough it sounds wicked, even with the bias setting very cold or very out of balance

soundwise, the old 2210 head of the other guitarist cannot even come close to my DSL on rehearsing volume (i'll bet he'll blow me away at full trottle, though)

i really do think it's the construction of the bias circuit which is giving the problems, when the amp has it's time of abuse... solderjoints, cracks in de PCB or whatever...
i just simply cannot believe it could be the brand new set of tubes

also i would like to know:
the JVM has a similar circuit, but its not on a separate PCB like the 2000's... do these things have drifting problems too? especially with the JJ's?
most JVM's are not older then 1 year... so... if they have drifting problems right there, it could be the tube's
if they don't have any of those problems, i really believe it's the construction of our beloved JCM2000's bias circuit, causing those problems... not the tubes

jcmjmp · 12-22-2008, 09:26 PM

Quote:

Originally Posted by big dooley

i really do think it's the construction of the bias circuit which is giving the problems, when the amp has it's time of abuse... solderjoints, cracks in de PCB or whatever...
i just simply cannot believe it could be the brand new set of tubes

Sometimes tubes become bad in transport or can just be bad from the factory. It happens.

luekemeyer · 12-22-2008, 09:35 PM

My bias voltage drifts up 2-4mv when they heat up. I'm using the KT77s... The original tubes were blown when I bought the head used. I think the JCM 2000 bias circuit most likely is the culprit and not as stable as it could be. If I was not so busy, I could use my electical engineering degree to see if there is a flaw, but.... I would rather watch TV and play the guitar.. hhhaaaa

dcooper830 · 12-22-2008, 11:48 PM

Here's a page that has wealth of JCM 2000 bias talk/info. Mostly centering on the poorly designed TSL 122.

But it has the identical bias pot set-up as the DSL 100.

The Marshall TSL122-JCM2000 Repair/Mods Page

There's a lot of technical info in there that I don't understand cause I know very little about all that stuff.

steelhorse · 12-23-2008, 12:44 AM

Great info cooper, thanks!

Brett Blackmore · 12-23-2008, 02:25 PM

Hi all,

I read the posts by the other forum guys with great interest - yet all this makes me a little sad to see external qualified specialists give Marshall hard, but truthful criticism about poor design and cheap money-saving materials - what the hell happened to Q&A with Marshall? I mean, with exception to signature amps and tranny amps they bring out a real new valve series every 5/7 years... don't they test these things?

I feel a little relieved as I have a DSL 100 which is still new but one day the pcb material will get brittle -but when? 6 weeks - 6 months - 6 years?

Cheers - from your frumpy old brittle Brett

jcmjmp · 12-23-2008, 07:56 PM

Quote:

Originally Posted by dcooper830

But it has the identical bias pot set-up as the DSL 100.

The Marshall TSL122-JCM2000 Repair/Mods Page

Post #4 - I already posted that link.

DragonSarc · 12-23-2008, 11:15 PM

bump

DragonSarc · 12-24-2008, 12:19 AM

OMFG!!!!!!!!!! im kicking my self in the head right now!!!IM a F@@king Idiot!!!!
my multimeter is set on mA not on mV thats why its hella low so stupid, i just waisted 100 bucks on set of new tubes theres probably nothing wrong with the old ones i got except for the loudness.

k so the amp is properly baised with the new tubes (might as well put the new ones in) but the volume is still low all the volume knob is on 12 o clock on OD gain full and the volume on clean is around 2 oclock gain is 12, its like its on VPR (VPR works i thought it was messing up), any one knows whats wrong with it? i tried switching the preamps and its the same, speaker blown? if it is it should sound dirty right and not all speakers would blow up at the same time, is there fuse inside the amp? i check the ones out side and thier clean.

:mad :

steelhorse · 12-24-2008, 02:31 AM

Are all the channels working? Do you get a distinct difference between clean, then to crunch, then ultra?

Is there distortion in the clean channel?

Is the foot switch functioning?

Are all the volumes set at 5?

DragonSarc · 12-24-2008, 04:51 AM

Quote:

Originally Posted by steelhorse

Are all the channels working? Do you get a distinct difference between clean, then to crunch, then ultra?

Is there distortion in the clean channel?

Is the foot switch functioning?

Are all the volumes set at 5?

yup all channels are working the od is a little louder than the clean but typical, the clean is a little distorted specially when the guitar is strum hard, havent tested the footswitch and yes all the volume is set at 5 which i never do because its unbearably loud specially on OD with the VPR off.

steelhorse · 12-24-2008, 08:35 AM

ok, I'm either misreading something here, confused or both. One post you said to wasn't loud enough on 5 and in another it's too loud on 5?

Also try turning all the channel volumes down to around 3, be sure the ultra button is engaged on the amp then use the ftsw to change the channels and see what happens.

stock_hippie · 12-24-2008, 08:50 AM

Quote:

Originally Posted by Brett Blackmore

Hi all,

I read the posts by the other forum guys with great interest - yet all this makes me a little sad to see external qualified specialists give Marshall hard, but truthful criticism about poor design and cheap money-saving materials - what the hell happened to Q&A with Marshall? I mean, with exception to signature amps and tranny amps they bring out a real new valve series every 5/7 years... don't they test these things?

I feel a little relieved as I have a DSL 100 which is still new but one day the pcb material will get brittle -but when? 6 weeks - 6 months - 6 years?

Cheers - from your frumpy old brittle Brett

sounds like Marshall is turning out some real junKK!

DragonSarc · 12-24-2008, 08:51 AM

Quote:

Originally Posted by steelhorse

ok, I'm either misreading something here, confused or both. One post you said to wasn't loud enough on 5 and in another it's too loud on 5?

Also try turning all the channel volumes down to around 3, be sure the ultra button is engaged on the amp then use the ftsw to change the channels and see what happens.

no no sorry steel, it used to be unbearbly loud on 5 before but now its like its on VPR mode, clean chanell a bit dirty on volume 5 gain on 4 it wasnt like that before either it wont really break up unless the gain is on 5, I just noticed too that at the back of the cab i plug the speaker cable to the left side plug instead of the right side switched on mono if that makes a difference?

jcmjmp · 12-24-2008, 11:05 AM

Quote:

Originally Posted by Brett Blackmore

Hi all,

I read the posts by the other forum guys with great interest - yet all this makes me a little sad to see external qualified specialists give Marshall hard, but truthful criticism about poor design and cheap money-saving materials - what the hell happened to Q&A with Marshall? I mean, with exception to signature amps and tranny amps they bring out a real new valve series every 5/7 years... don't they test these things?

I feel a little relieved as I have a DSL 100 which is still new but one day the pcb material will get brittle -but when? 6 weeks - 6 months - 6 years?

Cheers - from your frumpy old brittle Brett

Brett - I think that there is a run of TSLs that have this problem. Its not a wide spread problem as far as I know.

I wouldn't worry about it too much. I've had my DSL for 11years with no issues, and there are thousands of DSL owners out there with reliable DSLs.

I do think that quality went down at Marshall in the early 2000's but they seem to have resolved the issues.

dcooper830 · 12-24-2008, 11:17 AM

Quote:

Originally Posted by jcmjmp

Post #4 - I already posted that link.

Oooops. Sorry. I wasn't paying attention.

steelhorse · 12-24-2008, 05:53 PM

I was going to say that if the re-bias in winter thing were true I'd be in big trouble.

I own a lot of amps and I live in Alaska!

DragonSarc · 12-24-2008, 07:31 PM

steel I tested the pedal and it works but still have the same problem

steelhorse · 12-25-2008, 03:16 AM

And you say the amp does the same thing with the old pre amp tubes?

It could very well be that the new tubes are still getting settled and you may need to check for drift. If you don't think it sounds right contact Euro and -speak- to them directly by phone and let them know what's going on.

We need to rule the tubes out first and since it's a new set they should be able to help offer some assistance and advice as to why the sudden volume drop.

Do you think you killed the other tubes?

By biasing it improperly (mA instead of mV) you may have red plated the old set and prolonged exposure to that condition is not a good thing.

DragonSarc · 12-25-2008, 05:01 AM

yeah the amp does the same thing with the old and new tubes, I got the new tubes from guitar center cant wait for the mail (i thought its gonna fix it but didnt) I biased the new tubes with the right settings this time and still the same, I didnt change the preamp tubes, does the preamp tube gets affected by bad bias? so I might just take the amp to a tech and have it looked at, could you blow the cab speakers? (which i doubt it cuz i never cranked the cab that loud)

12-22-2008, 05:14 AM	#1 (permalink)
DragonSarc Senior Member Join Date: Jun 2008 Location: San Leandro, CA Posts: 495	rebais during winter? I replaced all my tubes from eurotubes this summer and only been played the TSL 100 amp no more than 20 hrs off and on with my attenuator no more than 4 hrs per play with vpr on and sometimes off, it was biased at 80 , now my amps volume decreased i checked the bias again and my multi meter is saying 30mv? ive switched the power tubes and pre amp tubes around and still the same, do you have to rebais the amp during winter cuz its colder? the bais shouldnt change once its set right unless the tube goes bad right? __________________ JVM410H w/ 1960 Vintage A & 1960 Lead B Valvestate 2000 AVT 100 W/ JJ tesla Hi-Gain Preamp Gibson LP studio faded mahagony w/ Burstbuckers Pro V MIJ ESP Edwards Les Paul w/ Duncan JB and 59's Fender American Strat w/ Noiseless Vintage pups LTD EC-500 Jackson Stealth Pro MIJ

12-22-2008, 06:33 AM	#2 (permalink)
Brett Blackmore Senior Member Join Date: Apr 2008 Location: Bingen, Germany Posts: 344	Re: rebais during winter? Hi, no. Winter / summer is irrelevant (sure a rehearsal room will be colder than at home but you know what I mean...). You have a tube down. Either it is not seated right or faulty. Cheers Brett

12-22-2008, 09:00 AM	#3 (permalink)
big dooley Senior Member Join Date: Sep 2008 Location: zealand, netherlands Posts: 397	Re: rebais during winter? JCM2000's have the irritating tendency to drift their bias, unfortunatly... i think it's a design-flaw which was more or less corrected in the JVM series, where the same biasing-system is moved to the inside of the chassis i keep checking the bias regularly, because it tends to drift too

12-22-2008, 04:34 PM	#5 (permalink)
DragonSarc Senior Member Join Date: Jun 2008 Location: San Leandro, CA Posts: 495	Re: rebais during winter? wow bad tubes already? it took the orig tubes to die about 4yrs how come the new ones died in few month? __________________ JVM410H w/ 1960 Vintage A & 1960 Lead B Valvestate 2000 AVT 100 W/ JJ tesla Hi-Gain Preamp Gibson LP studio faded mahagony w/ Burstbuckers Pro V MIJ ESP Edwards Les Paul w/ Duncan JB and 59's Fender American Strat w/ Noiseless Vintage pups LTD EC-500 Jackson Stealth Pro MIJ

12-22-2008, 05:06 PM	#6 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,888	Re: rebais during winter? If they're a month old they'll be covered by warranty if you bought them from a reputable dealer. They're just like anything else, sometimes a bad one slips through. Where'd you get them if you don't mind me asking? __________________ www.ricojronline.com 760-956-6619 Garmopat Pedal Mods "I wouldn't mind hearing your head smash through a glass door. That would be cool..." luekmeyer

12-22-2008, 05:34 PM	#7 (permalink)
dcooper830 Senior Member Join Date: Jul 2008 Posts: 120	Re: rebais during winter? I put a set of JJs from Eurotubes in one of my DSL 100s once. I kept having to set the bias cause it kept going way out. Finally I got tired of re-biasing and just kept using the amp until it started giving me high pitched screechy sounds intermittently. I didn't know what the problem was..... but when I checked the bias I was getting a ZERO reading on one side. I took it in for repair and the guy said a solder joint had gone out on the bias resistor or screen grid resistor....... I can't remember. In any event.. He repaired it and put in a new set of Svetlana tubes. The bias has been holding steady ever since. I think it was all because of bad JJs from Eurotubes. However...... I still like Bob and have always had good service from him. __________________ Videos of me playing guitar.

12-22-2008, 06:48 PM	#9 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,888	Re: rebais during winter? I suggest calling Euro Tubes right away and tell them what's going on. They should be able to help. It may be more than the tubes if it's reacting with the Euro set and the old set as badly as it is. That doesn't sound like a tube issue but perhaps a resistor issue. Like I said give them a call. __________________ www.ricojronline.com 760-956-6619 Garmopat Pedal Mods "I wouldn't mind hearing your head smash through a glass door. That would be cool..." luekmeyer

12-22-2008, 07:03 PM	#10 (permalink)
DragonSarc Senior Member Join Date: Jun 2008 Location: San Leandro, CA Posts: 495	Re: rebais during winter? thanks steel will do hopefully it wont be costly __________________ JVM410H w/ 1960 Vintage A & 1960 Lead B Valvestate 2000 AVT 100 W/ JJ tesla Hi-Gain Preamp Gibson LP studio faded mahagony w/ Burstbuckers Pro V MIJ ESP Edwards Les Paul w/ Duncan JB and 59's Fender American Strat w/ Noiseless Vintage pups LTD EC-500 Jackson Stealth Pro MIJ

12-22-2008, 08:37 PM	#11 (permalink)
big dooley Senior Member Join Date: Sep 2008 Location: zealand, netherlands Posts: 397	Re: rebais during winter? well. what i would like to know... do non-JCM2000 amps have the same bias-drift problems with JJ's? i only read stories of DSL's and TSL's with drifting problems, which in my opion cannot be blamed on the tubes if 800's, 900's, mk2's etc etc don't have those problems... this evening i found out the bias in my DSL100 was drifted again with the KT77's oddly enough it sounds wicked, even with the bias setting very cold or very out of balance soundwise, the old 2210 head of the other guitarist cannot even come close to my DSL on rehearsing volume (i'll bet he'll blow me away at full trottle, though) i really do think it's the construction of the bias circuit which is giving the problems, when the amp has it's time of abuse... solderjoints, cracks in de PCB or whatever... i just simply cannot believe it could be the brand new set of tubes also i would like to know: the JVM has a similar circuit, but its not on a separate PCB like the 2000's... do these things have drifting problems too? especially with the JJ's? most JVM's are not older then 1 year... so... if they have drifting problems right there, it could be the tube's if they don't have any of those problems, i really believe it's the construction of our beloved JCM2000's bias circuit, causing those problems... not the tubes

12-22-2008, 09:35 PM	#13 (permalink)
luekemeyer Senior Member Join Date: Nov 2008 Location: Calif Posts: 439	Re: rebais during winter? My bias voltage drifts up 2-4mv when they heat up. I'm using the KT77s... The original tubes were blown when I bought the head used. I think the JCM 2000 bias circuit most likely is the culprit and not as stable as it could be. If I was not so busy, I could use my electical engineering degree to see if there is a flaw, but.... I would rather watch TV and play the guitar.. hhhaaaa __________________ --------------------------------------------------- http://www.youtube.com/Earnhardt12345 JCM 2000 DSL 100 & MC412 Cab Crate Blue Voodoo BV-120H and 4x12 Cab ADA 1/2 Cab POD X3 Live VOX ToneLab Tube Screamer Flanger Phase 90 Chorus Crybaby Wah Epi Les Paul Plus Top - Dimarzio Super Distortions Dean Dime Shadow ML - Dimebucker bridge Ibanez RG - Van Halen II paint job - Dimebucker Kramer Aerostar Fender Squire Strat(From Corona Plant employee sale)

12-22-2008, 11:48 PM	#14 (permalink)
dcooper830 Senior Member Join Date: Jul 2008 Posts: 120	Re: rebais during winter? Here's a page that has wealth of JCM 2000 bias talk/info. Mostly centering on the poorly designed TSL 122. But it has the identical bias pot set-up as the DSL 100. The Marshall TSL122-JCM2000 Repair/Mods Page There's a lot of technical info in there that I don't understand cause I know very little about all that stuff. __________________ Videos of me playing guitar.

12-23-2008, 12:44 AM	#15 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,888	Re: rebais during winter? Great info cooper, thanks! __________________ www.ricojronline.com 760-956-6619 Garmopat Pedal Mods "I wouldn't mind hearing your head smash through a glass door. That would be cool..." luekmeyer

12-23-2008, 02:25 PM	#16 (permalink)
Brett Blackmore Senior Member Join Date: Apr 2008 Location: Bingen, Germany Posts: 344	Re: rebais during winter? Hi all, I read the posts by the other forum guys with great interest - yet all this makes me a little sad to see external qualified specialists give Marshall hard, but truthful criticism about poor design and cheap money-saving materials - what the hell happened to Q&A with Marshall? I mean, with exception to signature amps and tranny amps they bring out a real new valve series every 5/7 years... don't they test these things? I feel a little relieved as I have a DSL 100 which is still new but one day the pcb material will get brittle -but when? 6 weeks - 6 months - 6 years? Cheers - from your frumpy old brittle Brett

12-23-2008, 11:15 PM	#18 (permalink)
DragonSarc Senior Member Join Date: Jun 2008 Location: San Leandro, CA Posts: 495	Re: rebais during winter? bump __________________ JVM410H w/ 1960 Vintage A & 1960 Lead B Valvestate 2000 AVT 100 W/ JJ tesla Hi-Gain Preamp Gibson LP studio faded mahagony w/ Burstbuckers Pro V MIJ ESP Edwards Les Paul w/ Duncan JB and 59's Fender American Strat w/ Noiseless Vintage pups LTD EC-500 Jackson Stealth Pro MIJ Last edited by DragonSarc; 12-24-2008 at 02:00 AM.

12-24-2008, 12:19 AM	#19 (permalink)
DragonSarc Senior Member Join Date: Jun 2008 Location: San Leandro, CA Posts: 495	Re: rebais during winter? OMFG!!!!!!!!!! im kicking my self in the head right now!!!IM a F@@king Idiot!!!! my multimeter is set on mA not on mV thats why its hella low so stupid, i just waisted 100 bucks on set of new tubes theres probably nothing wrong with the old ones i got except for the loudness. k so the amp is properly baised with the new tubes (might as well put the new ones in) but the volume is still low all the volume knob is on 12 o clock on OD gain full and the volume on clean is around 2 oclock gain is 12, its like its on VPR (VPR works i thought it was messing up), any one knows whats wrong with it? i tried switching the preamps and its the same, speaker blown? if it is it should sound dirty right and not all speakers would blow up at the same time, is there fuse inside the amp? i check the ones out side and thier clean.:mad : __________________ JVM410H w/ 1960 Vintage A & 1960 Lead B Valvestate 2000 AVT 100 W/ JJ tesla Hi-Gain Preamp Gibson LP studio faded mahagony w/ Burstbuckers Pro V MIJ ESP Edwards Les Paul w/ Duncan JB and 59's Fender American Strat w/ Noiseless Vintage pups LTD EC-500 Jackson Stealth Pro MIJ Last edited by DragonSarc; 12-24-2008 at 02:04 AM.

12-24-2008, 02:31 AM	#20 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,888	Re: rebais during winter? Are all the channels working? Do you get a distinct difference between clean, then to crunch, then ultra? Is there distortion in the clean channel? Is the foot switch functioning? Are all the volumes set at 5? __________________ www.ricojronline.com 760-956-6619 Garmopat Pedal Mods "I wouldn't mind hearing your head smash through a glass door. That would be cool..." luekmeyer

12-24-2008, 08:35 AM	#22 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,888	Re: rebais during winter? ok, I'm either misreading something here, confused or both. One post you said to wasn't loud enough on 5 and in another it's too loud on 5? Also try turning all the channel volumes down to around 3, be sure the ultra button is engaged on the amp then use the ftsw to change the channels and see what happens. __________________ www.ricojronline.com 760-956-6619 Garmopat Pedal Mods "I wouldn't mind hearing your head smash through a glass door. That would be cool..." luekmeyer

12-24-2008, 05:53 PM	#27 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,888	Re: rebais during winter? I was going to say that if the re-bias in winter thing were true I'd be in big trouble. I own a lot of amps and I live in Alaska! __________________ www.ricojronline.com 760-956-6619 Garmopat Pedal Mods "I wouldn't mind hearing your head smash through a glass door. That would be cool..." luekmeyer

12-24-2008, 07:31 PM	#28 (permalink)
DragonSarc Senior Member Join Date: Jun 2008 Location: San Leandro, CA Posts: 495	Re: rebais during winter? steel I tested the pedal and it works but still have the same problem __________________ JVM410H w/ 1960 Vintage A & 1960 Lead B Valvestate 2000 AVT 100 W/ JJ tesla Hi-Gain Preamp Gibson LP studio faded mahagony w/ Burstbuckers Pro V MIJ ESP Edwards Les Paul w/ Duncan JB and 59's Fender American Strat w/ Noiseless Vintage pups LTD EC-500 Jackson Stealth Pro MIJ

12-25-2008, 03:16 AM	#29 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,888	Re: rebais during winter? And you say the amp does the same thing with the old pre amp tubes? It could very well be that the new tubes are still getting settled and you may need to check for drift. If you don't think it sounds right contact Euro and -speak- to them directly by phone and let them know what's going on. We need to rule the tubes out first and since it's a new set they should be able to help offer some assistance and advice as to why the sudden volume drop. Do you think you killed the other tubes? By biasing it improperly (mA instead of mV) you may have red plated the old set and prolonged exposure to that condition is not a good thing. __________________ www.ricojronline.com 760-956-6619 Garmopat Pedal Mods "I wouldn't mind hearing your head smash through a glass door. That would be cool..." luekmeyer

12-25-2008, 05:01 AM	#30 (permalink)
DragonSarc Senior Member Join Date: Jun 2008 Location: San Leandro, CA Posts: 495	Re: rebais during winter? yeah the amp does the same thing with the old and new tubes, I got the new tubes from guitar center cant wait for the mail (i thought its gonna fix it but didnt) I biased the new tubes with the right settings this time and still the same, I didnt change the preamp tubes, does the preamp tube gets affected by bad bias? so I might just take the amp to a tech and have it looked at, could you blow the cab speakers? (which i doubt it cuz i never cranked the cab that loud) __________________ JVM410H w/ 1960 Vintage A & 1960 Lead B Valvestate 2000 AVT 100 W/ JJ tesla Hi-Gain Preamp Gibson LP studio faded mahagony w/ Burstbuckers Pro V MIJ ESP Edwards Les Paul w/ Duncan JB and 59's Fender American Strat w/ Noiseless Vintage pups LTD EC-500 Jackson Stealth Pro MIJ

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