Resurrected Peavey Triumph 60

[stoneattic]

My transistor has 8097 on it as well. Does your LED come on when in standby?

I have it partially disassembled at the moment so I can't test at C30, but I will get it back together later today and check.

I think that the reason measuring voltage at the standby switch would get the volume back is that doing that would drain the coupling caps to ground, kind of a reset. Does that make sense?

This thing is really begining to p*ss me off, grrrr.

[nashvillebill]

Boy I gotta think about the status LED...come to think of it, it is ON when the amp is operational (not in standby)...I'm pretty sure! (I can't fire it up now to doublecheck, I've already got it loaded in the truck for tonight.) This would be consistent with every other amp I own, it also means the manual is wrong.

I follow your logic that it might be "resetting" the coupling caps. Try to measure the voltage on Pin1 to ground and Pin 6 to ground for each preamp tube, write them down. Do this when the amp is operating normally, then re-check them when it goes south.

[stoneattic]

I decided to bite the bullet and reflow every single solder joint on all the PCBs. That seems to have done the trick. I had it plugged in on the bench and played for 20 minutes with out a problem. It always started giving me problems with in the first five before.

We'll see how she hold up at band practice on Thursday.

Thanks for all the help!

[nashvillebill]

Good deal!

Mine unfortunately did not fare so well tonight. It began to get quieter throughout the 4 hours of playing and then it lost all sound output altogether. This is after putting maybe 30 hours of playing time on it without any previous issues....

[stoneattic]

That's disappointing. Is there any way to make these reliable?

I'm not going to be of much help but suggest reflowing ALL the PCB joints. I added solder in most places as they seemed a bit light on solder. Of course you had way more hours of trouble free operation than I had, and mine might go back to being a headache the next time I plug it in.

A few things I plan on doing to improve reliability:

1. Add/replace hot glue on the large components. I had some just fall off when I was reflowing the boards and some aren't really attached anymore and don't appear to be doing anything. I'm hoping that would reduce the physical load on the solder joints.

2. Replace the molex connector with something soldered instead of the IDC type. I like the idea of retaining the ease of maintenance of connectors instead of soldering, but don't trust the IDC.

3. Ceramic tube sockets all around and a some sort of tube retainer on V5.

[nashvillebill]

I had glued all the large components down, all IDC connectors were removed and soldered direct, all sockets have been replaced with ceramic on mine. All coupling caps have been replaced. All electrolytics have been replaced. I replaced most of the resistors with metal film. All relays were replaced. So I figured it should be reasonably reliable now, guess I was wrong...

After unloading the truck this morning, I plugged a dummy load on the amp and put the scope on it. The amp is now working, the sine wave in the clean channel looks good. Its possible I have a heat-related issue; it was very hot last night (outdoor gig) with the sun directly on the amp for quite a while. Peavey should've put a cooling fan in it, since there's a lot of stuff in a tiny area with minimal air flow.

I'm going to leave it on for a while with the dummy load all afternoonon to see what happens. I have already noticed some fluctucation in output. Plugged into the dummy load of nominal 8 ohms, it was starting to clip around 21 volts as measured with my Fluke, which is about what I expect. So I backed it off to around 18 volts and ahve left it there for an hour already. Without changing anything, it'd occassionally slowly fluctuate up or down a volt or more. (My dummy load's a non-inductive rated 100 watt, mounted on a big heat sink with a fan blowing on it).

[stoneattic]

It sure looks like you've covered your bases. It's really disappointing that you need to go that far and are still having issues. Hopefully you had a back up yesterday?

I played mine for 20 minutes or so again today with out any problems.

Let us know what you find.

[Lostfollicles]

Hi Guy's! Does anyone have any mods that i can do to my Peavey Triumph 60 Combo apart from the diodes and the tone mod which i have done?
I want the voicing on the Crunch/Ultra channels to match the clean channel i.e. with lots more bass and highs!
I know this is a common problem with this amp but has anyone modded this thing to sound more bluesey rather than grungy??
I even tried bypassing V2 which certainly brought back the bass and highs but of course i lost all the gain!

Help please anyone!

Regards

Lostfollicles

[nashvillebill]

I'm certainly no expert on amp voicings, but it's my guess that Peavey wanted this to compete with high-gain Mesas. They voiced it to follow the same strategy, which was to cut the bass and highs, leaving a highly overdriven midrange. If you look at the values of the coupling caps in the Crunch/Ultra channel, and run them through one of the coupling cap calculators, you can see how they cut the bass.

If you wanted to increase the bass through this gain stage, by changing coupling caps, I believe you will wind up with a very muddy sound unless you decrease the gain. I tried putting a 5751 in V2 in an attempt to lower the gain. It did but I wasn't happy with the result. I was trying to get a softer overdriven sound on the Crunch channel, hoping then the Ultra would be more like the original Crunch. I wasn't thrilled and I've gone back to the original 12AX7 in V2.

As far as my latest post with respect to the amp going silent at out last gig: since then I've put it on the dummy load cranked at almost full volume for many hours. Nothing happened. The voltage fluctuations that I thought I was observing turned out to be an instrumentation glitch. God I hate intermittent problems. At one point I had two scopes and 3 voltmeters all connected to the darn thing.

[Lostfollicles]

Hi Nashvillebill

Thank you for your reply!

I have been looking at changing/removing the cathode cap values on V2 as these from what I can gather from this great site: > The Valve Wizard (Download the .pdf file!!)
As these are also connected to the gain stage voicing but as yet I haven't got around to experimenting!

Oh! yeah when I had the pre-amp board out to re-connect V2 again after my failed mod! lol
I noticed a burnt looking connection on one of the Molex connectors coming off the power-amp board so I pulled it out and resoldered the connection from the pin to the board which also looked as if it had been hot at some stage, I then carefully pressed and pulled the pinch pin from the molex connector which looked fine (Not burnt) and then soldered the burnt looking wire to the top of it! I think I can safely say that that duff connection probably had a good deal to do with some of the amps duff sound problems as it was something to do with the biasing of the power tubes! I then changed V2 to a 12AY7 which made a big difference to the distortion (Not quite so fizzy) so I've left that tube in!

I would still like to change the voicing on crunch/ultra to at least get a bit more bass and highs and hope that I can achieve this without the gain stage motorboating or overloading! Also from what I have gleaned from the web it looks like the stock speaker is too cardboard sounding so I might have to start saving my money!

Other than that this amp is a beast and built like a tank and when those channels are voiced to my liking I will love it even more!

Thanks again bill for your help if you have any other advice/tweeks it would be welcome!

Regards

Lostfollicles

[stoneattic]

So I tried using the Triumph at practice last night and ended up having to go back to my Mesa DC-2. The Triumph is just too thin and "ice picky" no matter what I did with the EQ or tone knob on the guitar. Is that how these guys sound or do I have something else going on? I don't remember it sounding like that previously but I never tried using it with the band and never A/B'ed it against anything else before.

I plugged Triumph into the Mesa's speaker to see if that was the tone difference, but it wasn't. I retubed the Triumph just to be sure it's wasn't a tube going south but it still sounds the same.

Also, has anyone who has done the tone mod by clipping the jumper near the Low EQ notice that now the High EQ also acts as a volume or do I have something else weird going on?

[nashvillebill]

Mine doesn't seem to act like that, are you sure the right one is clipped? You can see it in this picture.

Was the Bright switch pushed in? Was this in all channels including normal, or just the Ultra/Crunch?

I reflowed the solder connections on mine where the PT plugs into the power board for the heater supply. Other than that I can't find anything wrong on mine that might've caused it to drop out....except...the tubes are almost brand new, but they're very noisy (mechanical vibration) on certain notes. They're JJ's and at times it almost sounds like a jar of coins being shaken. There also might be some occasional speaker voice coil noise. I'm going to plug it in to an external cab to see what's happening. I have been considering changing this to just a head rather than a combo.

Lostfollicles, I haven't played any more with coupling caps or cathode caps. It could be beneficial but this amp is such a PITA to work on, I'm tired of taking it apart (especially now that I've soldered all the jumpers between the board). But if I were to experiment, I don't think I'd use tube theory books to hand-calculate the values (though the theory is great to know). There are sites like this one Coupling Capacitor Calculator that have nifty little scripts already written to calculate the resulting frequency response. (This page was coupling caps but the site also has cathode caps.) The other equally valid approach would be to duplicate an existing amp's gain stage design.

Back to my amp:
Frankly, I'm beginning to reach the stage where I'm getting somewhat disenchanted with it. The sound is OK--clean is quite good, Crunch has a great rock crunch, and if I was playing distorted leads, Ultra would be great high-gain. But the reliability has me concerned; it weighs a frickin' ton, and I believe making this into such a small combo has been a poor compromise from an engineering standpoint. The "tube hanging down" design in such a small package means heat is trapped in the chassis. If they had made the chassis an inch deeper (front to back) and just slightly wider, they wouldn't have had to stack the circuit boards. If it just weren't so noisy ("hiss")....

Peavey could've hit one out of the ball park with this amp but they missed.

[stoneattic]

I believe I have the correct one clipped. Here's a pic of my clipped jumper as well as the diode bypass. Did I do the correct one?

I notice that we have different caps and resistor values near that jumper. Looking at the schematic it seems like the High EQ would act as a volume since it seems to me that the signal passes through that on the way to VB3. Am I reading it wrong?

So you're thinking that one of the new tubes may be flaky on yours?

[nashvillebill]

Only the highs are attenuated, although the signal passes through the pot--it acts like a voltage divider I believe, but I'm no tone stack expert. Try playing with the Fender tone stack at Duncan's tone stack calculator Download The Peavey is sorta similar but not quite the same.

My amp must be an early production run. The later runs have a different board date on a couple of boards (you can see them on the board layout with the schematics). Mine doesn't have R97,R98 or C53.

I don't think the power tubes are flaky in the sense that I don't believe they are causing any electronic problems, but like other combo amps I've had, the speaker vibrations eventually make the tubes rattle when you hit certain notes. Very annoying.

[stoneattic]

The TSC is pretty cool. It's going to take me a while to understand it though. I'm been trying to learn as much as I can about tube amps. I just scored an old Tektronix O-scope to play with. I've been reading tones of tube amp books (The Ultimate Tone by Kevin O'Conner, The Guitar Amp Handbook by Dave Hunter, etc) but I'm still a relative newbie.

So if you turn the High EQ down to zero, does the amp go silent? If not, then I must still have a problem, not just a tone I'm not digging.