Gear issues last night, glad I brought a backup. (kinda long

[The_Kid]

So about 7 months ago I had an issue with my JSX, where it would intermittently cut out to almost no volume at all. I tried everything, cables and tubes, and nothing would reproduce this everything, nor lead me down any path to a solution as to what is causing the problem. So I took it to my local guy here and he found a piece that was charred black. Cleaned it off, and its been fine for the past 7months.

Recently I have been getting into the pedal thing. Bought a chorus, tuner and a blues driver as a lead boost. I noticed the past couple shows that a couple of times when I would turn on my blues driver I had no volume. Checked the knobs, and all is where my happiness comes from that pedal. So I turn it off, and on and its fine. Solo wasted, move on. Then a song or two later, same thing, only this time it doesn't come back. So now I'm thinking its a bad jack or something, so I start removing things from my chain. Take the boost out. Still no volume. Take the wah pedal out, cause its a BYOC Wah, and if theres a problem for sure, its probably coming from something I built. Take the wah out, no sound. Ok, maybe its the wireless, although never had a problem dropping out or anything. I plug straight to the TU-2, then Amp, Chorus in the loop, Cab.

Works fine. Until...

I turn my chorus off. Then no sound again. I turn my chorus back on, nothing. So I remove the chorus. Still nothing. At this point I just remove all cables from my amps loop. I'm now running Guitar - TU-2 - Amp - Cab.

Nothing.

At this point I'm ready to just give up. THe band is trying to carry on as best they can without me, but a mediocre rhythm player at best cannot cover for a lead player, especially when they don't know the parts. lol.

Then I remember I have a back up amp in my car. The good ol' Fender Cyber Twin Head. NEver let me down, might as well try it.

Plug it in, just guitar, amp cab. Nothing. So Now I think its got to be the cab. probably the jack on the back, cause as stated before, I rebuilt the cab and did the wiring myself...so thats probably where it will happen. I check the back of the cab...and the jack's washer is slightly unscrewed. I tighten it up, retune, turn the tuner off...and voila. SOUND!!!

So now I know it has to be something with the amp. Any ideas, help, places I can send it....or if anyone in the WI or Green Bay area knows someone who can diagnose this for me, and check my amp out from top to bottom, I'd appreciate it. I do not like gigs like this, as I"m pretty sure no one does.

As always, thanks for listening and any help. Be sure to tip your waitress, and try the veal, I'm here all week.

 

[The_Kid]

I also run some rack gear as in my sig. WHen the problems were happening, the first thing I check usually, is where can I Detect my signal is dying. I checked my ISP Noisegate in my rack. I had signal tripping the CH.2 meter. Which means the signal was being lost after it left the ISP, went into the return of my amp, and to the cab....

 

[glpg80]

when you have sound coming out.. is it EXTREMELY low audible sound that cant be adjusted for volume no matter how much you turn it up?

if so, i know the problem =]

whatever "charred" piece he cleaned off inside the amp means there was a current runaway or a spike a failed component. inside peavey amps (especially all of the the 5150 series) there are about 6 different hard-wired relays on the pre-amp board that act like life savers and bust open to prevent a spike ruining the entire preamp.

they are placed all over it, like little life-savers.

if one of them are blown or shorting because of an "almost" blow your sound will cut to nothing, but be audible juuuuuuuuuust a little and no matter what EQ knobs you turn or volume knobs you turn nothing is gonna get louder. you may get more hiss but no volume increase.

thats my recommendation being the cab is ruled out and cables as well

-matt

 

[The_Kid]

Initially, that was the case...whether the master was on 1 or dimed. THe volume didnt really change. Although it would be intermittent. Come and go for no reason. I did get barely bedroom level by diming all the volumes and such. But that was a blast when the volume came back.... although I think the soundwave blew my nuts off...

Anyway, the problem now, is that there is no sound whatsoever when it does it. Its not the same problem as before...this time there is no sound...

 

[glpg80]

could be a loose solder. time to go chopstick tapping

or it could be both, because thats the same effect as a full blow.

i dont know what those little guys are called. it took me and another certified tube amp guy almost 3 weeks to figure out my 5150II. it did the same thing except mine was a loud POP and i looked back on stage and my amp was basically fucked. power tubes werent glowing and the standby/power LEDs were off but the switches were on. it decintegrated the slow blow fuse to a blackened char. we both came to the conclusion something arced inside the amp to the preamp board.

thats mixing ~500 volts with components rated at 50V max.

but yeah dude could be a loose solder you really just dont know until you dive in there with a schematic and start troubleshooting.

i think its pre-amp based. as we know the volume works

just a matter of finding what and where and even more important WHY..

 

[The_Kid]

I think you are confusing the previous problem with this one. Its not the same issue, and I'm not hearing the same issues this time.

Last time - Low volume, all levels dimed equaled barely bedroom level.

This time - no volume, I play with master dimed, and adjust channels accordingly, but even dimed no extra hiss or sound...


This may be an advanced version of the previous, but I'm hearing and seeing different things. The power lights were still on, the tubes were still glowing that I remember.

 

[glpg80]

OOOOOOOOOH



i was understanding it as you took it to have the first problem fixed but it came about doing the same thing AGAIN.... and on top of the reaccured problem the amp also just quit giving sound after the fact that it had been fixed.

if this is no where near the same thing, which means pass the small volume issue and go straight to no volume at all this time around, then theres most definately a problem in the power-amp side. you should hear hiss (even small ammounts) with the master dimed and the pre-amp channel volumes up. thats just because its a high-gain amplifier and the gain stages are notorious for hiss at loud volumes (small amounts now we arent talking about grounding problems or interference with the wiring)

if thats the case i myself would start in the power-amp section and work my way backwards through the phase inverter stage on the pre-amp board. theres gotta be a problem somewhere =]

again, sorry for the mis-read

 

[The_Kid]

no problem. I'm not the best person to describe some of this stuff cause I"m not much of a 'guts' techie. I'm gonna wire everything up again this afternoon and see if I can't find some more information to help solve this. I'm not the person to be taking an amp apart and 'test' things...lol...I'll have to take it to a different amp guy.

Maybe J.B. knows someone reliable that I can take it to, being that he lives only 25 miles from me. lol...

 

[D-Rock]

If you suspect it's a poweramp problem and the all the big bottles are glowing evenly, I would try a swap of the Phase Inverter 12AX7 that sits next to the poweramp tubes. This 12AX7 is actually part of the poweramp, not the pre. Peavey calls this position the phase inverter, and calls the tube a poweramp driver.

It's an easy test for elimination purposes.

 

[The_Kid]

Can I just swap one of the other preamp tubes for it? would that give me the same result if that tube is bad? or do I need to swap it with a new one.

 

[D-Rock]

Can I just swap one of the other preamp tubes for it? would that give me the same result if that tube is bad? or do I need to swap it with a new one.

Swap it with a 12AX7 that you know is in good/proper working condition. Doesn't have to be new. I wouldn't trade it for one already in the amp. Because if the PI tube is bad, then it will cause other issues in the slot you swapped it for.

 

[The_Kid]

I do have a XXX laying around that I can get a preamp tube from. I'm gonna get my stuff setup soon, and try it out with my JSX first to see if its still being a dick. If it is, I'll try the XXX in the same setup and see if it really is the amp, if it is, then I'll swap the preamp tube.

 

[glpg80]

If you suspect it's a poweramp problem and the all the big bottles are glowing evenly, I would try a swap of the Phase Inverter 12AX7 that sits next to the poweramp tubes. This 12AX7 is actually part of the poweramp, not the pre. Peavey calls this position the phase inverter, and calls the tube a poweramp driver.

It's an easy test for elimination purposes.

actually phase inverter stage is a stage that the tube itself acts as a buffer and requires a clean tube, NOT a 12AX7, that is even on both triodes SIDE A and SIDE B, it balances the signal of the preamp garbage to be sent to the power-amp to be amplified. you can put 12ax7's in the phase inverter stage for more gain but thats not the circuits intention or design. although mods do exist to turn the phase inverter stage into a V# gain stage.

it also is not considered part of the power amp stage. its voltages arent 400V+ on the plates, they barely register 180 on mine. and its not a peavey only schematic use IE they didnt invent it.

although it is true its a common starting-place to testing to see if its either pre-- or power.

 

[The_Kid]

ok, well I'm assuming that the JSX and XXX being of similar design, have a similar PI tube in them. Assuming, that its both the farthest tube from the inputs, I should be able to swap the XXX into the JSX correct?

 

[glpg80]

ok, well I'm assuming that the JSX and XXX being of similar design, have a similar PI tube in them. Assuming, that its both the farthest tube from the inputs, I should be able to swap the XXX into the JSX correct?

yes peavey normally puts the phase inverter stage tube as the last tube to the left looking at the back of the amp. just find the tubes that are either 12au7 (i think thats the tube peavey uses as the PI stage stock) on both amps and swap-em out.

but i honestly dont think swapping the tubes will do any good. you arent having issues of microphonic tubes. but yes sir to answer your question you can switch the PI tubes out of each amp without any problems to get an idea and/or see if that solves your problem

EDIT:

honestly bro the guys over at metro-amps non-marshall topic might be able to give you a hand on troubleshooting it further. but again if you dont feel comfortable opening her up dont try. we dont need one less musician in this world

 

[The_Kid]

but again if you dont feel comfortable opening her up dont try. we dont need one less musician in this world

Yeah I stay away from anything involving electrical shit most times. I'll turn things on and off with switches and such. My best bud has the death wish. lol. I've had enough zaps from bad grounding of PA's through mic stands, and such, I care not to learn of other ways.

 

[glpg80]

but again if you dont feel comfortable opening her up dont try. we dont need one less musician in this world

Yeah I stay away from anything involving electrical shit most times. I'll turn things on and off with switches and such. My best bud has the death wish. lol. I've had enough zaps from bad grounding of PA's through mic stands, and such, I care not to learn of other ways.

grabbing hold of 400V's would throw you off your feet, numb your whole body, and forget about being able to talk or walk for a good hour. and thats IFF.. it doesnt defibb your heart to stop

theres a rules checklist to go through though. and rules to follow while inside the amp. like only 1 hand at a time when its on and draining caps FULLY and checking for gator clips that are clipped where they shouldnt be

im guilty of the last one sadly. live and learn =0

 

[D-Rock]

If you suspect it's a poweramp problem and the all the big bottles are glowing evenly, I would try a swap of the Phase Inverter 12AX7 that sits next to the poweramp tubes. This 12AX7 is actually part of the poweramp, not the pre. Peavey calls this position the phase inverter, and calls the tube a poweramp driver.

It's an easy test for elimination purposes.

actually phase inverter stage is a stage that the tube itself acts as a buffer and requires a clean tube, NOT a 12AX7, that is even on both triodes SIDE A and SIDE B, it balances the signal of the preamp garbage to be sent to the power-amp to be amplified. you can put 12ax7's in the phase inverter stage for more gain but thats not the circuits intention or design. although mods do exist to turn the phase inverter stage into a V# gain stage.

it also is not considered part of the power amp stage. its voltages arent 400V+ on the plates, they barely register 180 on mine. and its not a peavey only schematic use IE they didnt invent it.

although it is true its a common starting-place to testing to see if its either pre-- or power.

The Peavey JSX and XXX use 12AX7's for the PI spot. This tube can be balanced as well as not balanced and will operate normally either way. The stock PI tube in the JSX is a Sovtek LPS 12AX7.
Basically it's such an easy test to determine/rule out the PI as being the problem. One simple swap. If it solves the problem great, if not...next idea.

 

[Cornfordcrunch]

So about 7 months ago I had an issue with my JSX, where it would intermittently cut out to almost no volume at all. I tried everything, cables and tubes, and nothing would reproduce this everything, nor lead me down any path to a solution as to what is causing the problem. So I took it to my local guy here and he found a piece that was charred black. Cleaned it off, and its been fine for the past 7months.

Recently I have been getting into the pedal thing. Bought a chorus, tuner and a blues driver as a lead boost. I noticed the past couple shows that a couple of times when I would turn on my blues driver I had no volume. Checked the knobs, and all is where my happiness comes from that pedal. So I turn it off, and on and its fine. Solo wasted, move on. Then a song or two later, same thing, only this time it doesn't come back. So now I'm thinking its a bad jack or something, so I start removing things from my chain. Take the boost out. Still no volume. Take the wah pedal out, cause its a BYOC Wah, and if theres a problem for sure, its probably coming from something I built. Take the wah out, no sound. Ok, maybe its the wireless, although never had a problem dropping out or anything. I plug straight to the TU-2, then Amp, Chorus in the loop, Cab.

Works fine. Until...

I turn my chorus off. Then no sound again. I turn my chorus back on, nothing. So I remove the chorus. Still nothing. At this point I just remove all cables from my amps loop. I'm now running Guitar - TU-2 - Amp - Cab.

Nothing.

At this point I'm ready to just give up. THe band is trying to carry on as best they can without me, but a mediocre rhythm player at best cannot cover for a lead player, especially when they don't know the parts. lol.

Then I remember I have a back up amp in my car. The good ol' Fender Cyber Twin Head. NEver let me down, might as well try it.

Plug it in, just guitar, amp cab. Nothing. So Now I think its got to be the cab. probably the jack on the back, cause as stated before, I rebuilt the cab and did the wiring myself...so thats probably where it will happen. I check the back of the cab...and the jack's washer is slightly unscrewed. I tighten it up, retune, turn the tuner off...and voila. SOUND!!!

So now I know it has to be something with the amp. Any ideas, help, places I can send it....or if anyone in the WI or Green Bay area knows someone who can diagnose this for me, and check my amp out from top to bottom, I'd appreciate it. I do not like gigs like this, as I"m pretty sure no one does.

As always, thanks for listening and any help. Be sure to tip your waitress, and try the veal, I'm here all week.

Forgive me if this was suggested and I missed it in the threads...but if your power tubes are glowing and you arent getting any sound or even hiss, I'd check the HT fuse. If its bad, replace and if it pops it again, I'd bet its a bad power tube.

 

[D-Rock]

^^^^^Another good suggestion ^^^^^