It's a pity that you are far from here. I have a similar issue with my AC30. It's good to see serious and professional people. Thanks! Cheers from Italy. Zep.
I appreciate you usually reaching for your Stratocaster for the sound demos. I've watched enough of your videos that I'm starting to be able to discern the difference in tone the different amplifiers provide as well as when there is a problem with them. Its a small thing but I appreciate it. Thank You
Nice to see a Peavey video! Just today, went out with my nephew and purchased a Peavey Penta 140 head for him. He’s borrowing my Carvin Belair 2x12 combo for the speakers, until he figures out something for a cabinet. Can’t wait to open it up and service/mod it.
appreciate the vid, just fixed mine, same issue, except the slow blow had a piece of the filament still attached so it was creating continuity on the meter, but amp wouldnt work, fixed all those stupid jumpers and a new fuse. good to go thanks!
Nice info. I own own of these beasts for 25 years. Used it moderately. No issues to date but I will consider the advice of your channel. Liked and subscribed.
Nicely done. While not as active in amp repair as I once was, I've seen many examples of 6BQ5/EL84 tubes set up to run really, really hot. Those tubes can take your skin off if you don't let 'em cool a tad before touching them after powering down.
This is over a year old but in my experience this amp suffers from the output tube socket solder joints coming loose. No better way to burn out a set of tubes. I've seen it twice now. The holes in the PCB's for the sockets are too large. Re flowing them is a necessity!
Interesting to note that I have a classic 50 / 4 and the control panel is tainted and pitted the same as this one . Great amp but would it really cost much more to treat the metal better
Where are you located, if you don't mind me asking. I own one these amps from the mid to late 90's and I might need a good repair man for those three underrated resisters that couse the amp to get kinda hot.
Hello, great channel. I was wondering if you could tell me what would cause the reverb in a peavey classic 20 mh to be weak. Even all the way up the reverb is just barely there. Ftom what Ive seen in demos it's supposed to fairly "lush", but on mine its more "dry" sounding. Thanks
Reverbs do often become weaker with age. Maybe those little magnets around the reverb springs demagnetize? They are available at several amp part supply distributors, at a reasonable price.
Looking up the classic 30 it had a cage design originally it wouldn’t surprise me if someone hasn’t worked on it and ended up losing the cage so they decided to throw that metal in front hoping it’ll do the trick instead of finding a replacement cage for it, not only was that Jerry rigging but also tacky and useless as protection.
Just out of interest - do you use a tube tester? I was thinking this could have been an interesting follow up to the brown/overheated tubes, just to prove your detective work.
All a tube tester does is apply filament, and B+ and a dc bias on the tube at two different values, while when You test a tube in an amp, and preferably look at it on a 'scope with an oscillator going through it at several different frequency's and levels tells You how much gain, linearity, and noise level, as well as if it is slightly gassy (microphonic). So You see an amp is a tube tester.
I had a client with a '93 Classic 50 call with a repair inquiry. With a tube set costing over 100, and with removal of the boards and watching the hinge wires snap, when do these amps approach "not worth fixing" status?
When it needs a new spider mount pot and there aren’t any left. Or if the board burns (there are two little resistors hidden between two caps and usually covered by glue that like to char). Definitely a case by case basis these days.
@@PsionicAudio I hear ya. But just like a Hot Rod Dlx, if you have to do a cap job, you might as well replace a lot of other things. Oddly, I find I have replaced a few power transformers on these, a normally high reliable part. I get a lot out of your vids and find I am sending clients here too. It is always good to know what you're in for before you buy something.
Ohms law, it is cheaper to buy a transformer to deliver the current needed by four resistances in series at high voltage rather than four in parallel at high current. Copper is expensive.
I was thinking about buying a similar amp from pawn shop. But l watching these videos have giving be doubt .There asking $750 Canadian for the amp. It has a 16ohm speaker in it .Seems like a high impedance ?
Schematic says 1A. I agree it's a bit more than needed, but better than no fuse at all. But know that I consider a lot more things than I might mention in a video. I tend to just do highlights of a service or focus on a particular issue. And overriding a factory fuse value is a big subject - and not something many amp owners should even consider. So I wouldn't do a video on that, as any misunderstandings on the viewer's part could lead to expensive mistakes.
As a new owner of a peavey classic 30 bought used…. The power tubes aren’t matched… 3 JJs and one groove tube…should I buy and retube with a matched quad and do I need to rebias thus amp
2W for the screen grids, but they have two 5W resistors in the power supply that toast the board.. Those need to be 5W but elevated off the board. See the after video.
@@PsionicAudio Decreasing the Screen Voltage and current will also Decrease the plate voltage and current which the output tubes are going to be operating at a different headroom
At some point it's semantics. I am retaining high plate voltage, lowering plate voltage and current, while maintaining the desired bias. Change anything in a system and other things change too - but this is a very good change. EL84s surprisingly sound better when they aren't dying. Go figure.
@@PsionicAudio changing the screen resistance is changing the operating bias of the operating points of the EL84. Lower Plate Voltage and Lower Screen Voltage is a different type of biasing because the EL84 is going to break up and distort at a different point because its a lower voltage.
@@waynegram8907 An EL84 can pull it's plate down to something like 75 volts each time the input signal swings positive. The screen grid will always be much higher than that unless the resistor is many many kohms.
These amps always have that horrible ice picky high end. I've grown a mild hatred of JJ tubes. The Mullard reissues are so much better sounding, especially in the power amp.
I’ve got an older one. I’ll keep these vids in my list for when I need to diagnose issues. So far it’s been a great amp for bedroom jams.
One thing I did to my 90s Classic 30 was to install a "Toms tube tamer" - a rigid cage that protects the tubes from damage!
These amps sound great with a Celestion V-Type driver. Impeccable work, as always.
It's a pity that you are far from here. I have a similar issue with my AC30. It's good to see serious and professional people. Thanks! Cheers from Italy. Zep.
Wow. It was just a fuse. These videos are great, and valuable information.
I appreciate you usually reaching for your Stratocaster for the sound demos.
I've watched enough of your videos that I'm starting to be able to discern the difference in tone the different amplifiers provide as well as when there is a problem with them.
Its a small thing but I appreciate it.
Thank You
Thanks!
The reason for the lack of grid protection is because like most products, it’s made to break so the user goes and buys another one.
Nice to see a Peavey video! Just today, went out with my nephew and purchased a Peavey Penta 140 head for him. He’s borrowing my Carvin Belair 2x12 combo for the speakers, until he figures out something for a cabinet. Can’t wait to open it up and service/mod it.
appreciate the vid, just fixed mine, same issue, except the slow blow had a piece of the filament still attached so it was creating continuity on the meter, but amp wouldnt work, fixed all those stupid jumpers and a new fuse. good to go thanks!
Nice info. I own own of these beasts for 25 years. Used it moderately. No issues to date but I will consider the advice of your channel. Liked and subscribed.
Nicely done. While not as active in amp repair as I once was, I've seen many examples of 6BQ5/EL84 tubes set up to run really, really hot. Those tubes can take your skin off if you don't let 'em cool a tad before touching them after powering down.
I use thick cloth gloves so I can pull valves (tubes) without having to wait for them to cool.
This is over a year old but in my experience this amp suffers from the output tube socket solder joints coming loose. No better way to burn out a set of tubes. I've seen it twice now. The holes in the PCB's for the sockets are too large. Re flowing them is a necessity!
Happened to my Classic 50
Nice job, very informative..Thanks for sharing..Ed..UK..😀
Nice video and helpful.
Thanks 👍
Interesting to note that I have a classic 50 / 4 and the control panel is tainted and pitted the same as this one . Great amp but would it really cost much more to treat the metal better
Thank you !
nice amps...owned a few...they run very hot...but can sound great...but I now use Boss Katana's as they don't have any of these issues...
Does running a fan help with the heat issues?
@@benlogan430 yep...
I use a fan on mine. It should help but mine has various issues, one being shoddy work by the last amp tech I took it to.
Where are you located, if you don't mind me asking.
I own one these amps from the mid to late 90's and I might need a good repair man for those three underrated resisters that couse the amp to get kinda hot.
Do you have a video with the mod for those screen-grid resistors?
DB, bit of a chore if gigging and blow fuse? mine lost power during rehearsal and couldnt get to fuses easily. shame as the sound is awesome.
I just uploaded a video on my channel talking about the Peavey Triumph 120/60 tube amplifiers common problems and how to fix them.
Hello, great channel. I was wondering if you could tell me what would cause the reverb in a peavey classic 20 mh to be weak. Even all the way up the reverb is just barely there. Ftom what Ive seen in demos it's supposed to fairly "lush", but on mine its more "dry" sounding. Thanks
Reverbs do often become weaker with age. Maybe those little magnets around the reverb springs demagnetize? They are available at several amp part supply distributors, at a reasonable price.
Those mini heads use digital reverb so you’ll have to take it to a tech
Looking up the classic 30 it had a cage design originally it wouldn’t surprise me if someone hasn’t worked on it and ended up losing the cage so they decided to throw that metal in front hoping it’ll do the trick instead of finding a replacement cage for it, not only was that Jerry rigging but also tacky and useless as protection.
Just out of interest - do you use a tube tester? I was thinking this could have been an interesting follow up to the brown/overheated tubes, just to prove your detective work.
I have one, but didn't feel the need to test these. Tubes that have been that hot aren't to be trusted.
All a tube tester does is apply filament, and B+ and a dc bias on the tube at two different values, while when You test a tube in an amp, and preferably look at it on a 'scope with an oscillator going through it at several different frequency's and levels tells You how much gain, linearity, and noise level, as well as if it is slightly gassy (microphonic). So You see an amp is a tube tester.
It sure looks to me like the two electrolytic filter caps on the upper left have leaked on the board and each other?
Nah, that’s the glue PV used. Copious amounts.
I had a client with a '93 Classic 50 call with a repair inquiry. With a tube set costing over 100, and with removal of the boards and watching the hinge wires snap, when do these amps approach "not worth fixing" status?
When it needs a new spider mount pot and there aren’t any left. Or if the board burns (there are two little resistors hidden between two caps and usually covered by glue that like to char).
Definitely a case by case basis these days.
@@PsionicAudio I hear ya. But just like a Hot Rod Dlx, if you have to do a cap job, you might as well replace a lot of other things. Oddly, I find I have replaced a few power transformers on these, a normally high reliable part. I get a lot out of your vids and find I am sending clients here too. It is always good to know what you're in for before you buy something.
Is this the one with the series-wired filaments on the EL84s? I'll never understand why Peavey chose to do that.
Ohms law, it is cheaper to buy a transformer to deliver the current needed by four resistances in series at high voltage rather than four in parallel at high current. Copper is expensive.
Psionic, sir, question for you...
1k 5W as well, or do you increase the power rating on those screen-grid resistors?
1K 2W per EL84. bradsguitargarage has a video where he shows this on a C30
@@PsionicAudio Oh, man, super appreciated, thank you !!!
I was thinking about buying a similar amp from pawn shop. But l watching these videos have giving be doubt .There asking $750 Canadian for the amp. It has a 16ohm speaker in it .Seems like a high impedance ?
16 ohm is the correct load for a Classic 30. But I cannot advise you on buying an amp from a pawn shop.
1A high tension? A 100w Marshall uses 1A... most dual EL84 250mA from memory. Would think 500 on this. Possibly replaced over spec already?
Schematic says 1A.
I agree it's a bit more than needed, but better than no fuse at all.
But know that I consider a lot more things than I might mention in a video. I tend to just do highlights of a service or focus on a particular issue.
And overriding a factory fuse value is a big subject - and not something many amp owners should even consider. So I wouldn't do a video on that, as any misunderstandings on the viewer's part could lead to expensive mistakes.
As a new owner of a peavey classic 30 bought used…. The power tubes aren’t matched… 3 JJs and one groove tube…should I buy and retube with a matched quad and do I need to rebias thus amp
You don't need to bias it - it's cathode bias. If you have hum or any 84 is glowing red, retube with a matched pair. But it may work fine as-is
Surely a 3W (1k) resistor would be enough for an EL84 SGR? I only use 5W for 6L6GCs!
2W for the screen grids, but they have two 5W resistors in the power supply that toast the board.. Those need to be 5W but elevated off the board. See the after video.
I about to get a classic 50 2x12 in the next couple days here. Real sleeper amps but tone is subjective I guess.
Changing the Screen Grid resistors from 100ohms to 1K ohms is a big difference in value which is changing the Bias of the output tubes?
No, doesn't affect the bias. Decreases the screen voltage and current.
@@PsionicAudio Decreasing the Screen Voltage and current will also Decrease the plate voltage and current which the output tubes are going to be operating at a different headroom
At some point it's semantics. I am retaining high plate voltage, lowering plate voltage and current, while maintaining the desired bias. Change anything in a system and other things change too - but this is a very good change.
EL84s surprisingly sound better when they aren't dying. Go figure.
@@PsionicAudio changing the screen resistance is changing the operating bias of the operating points of the EL84. Lower Plate Voltage and Lower Screen Voltage is a different type of biasing because the EL84 is going to break up and distort at a different point because its a lower voltage.
@@waynegram8907 An EL84 can pull it's plate down to something like 75 volts each time the input signal swings positive. The screen grid will always be much higher than that unless the resistor is many many kohms.
you kind of sound like Peter Steele
1A slow blow? No U didn't?
These amps always have that horrible ice picky high end.
I've grown a mild hatred of JJ tubes. The Mullard reissues are so much better sounding, especially in the power amp.
get a boss Katana
such a good sounding pile of junk...mine has been nothing but problematic...could never gig with this junk heap...worst design ever