Resurrected Peavey Triumph 60

[nashvillebill]

Thanks, I don't know if I will actually implement all of these mods in my amp or not. I have already increased C13 slightly, I don't remember what I put in.

I think Peavey was trying to cash in on the mid-80's screaming-gain hair metal crowd. Which might've been OK...for my needs, a 4 channel amp would be better: normal, slighlty overdriven/blues, crunch, and ultra-gain lead.

Maybe it'd be possible to add more drive (footswitchable even?) to the Normal channel. Or put the EQ section AFTER the gain stages, like the Classic 50.

[stoneattic]

What's your voltage measured from C42+ to ground? (chassis ground, not C42-)

This is DC but there will be ripple on it.

I just had an opportunity to check this and measuring the jumper between CR11/13 and C42 to chassis ground I get 495VDC. According to the schematic I should get 508VDC. I'm guessing 2.6% deviation is acceptable. So am I losing excessive voltage between there and power tubes?

[nashvillebill]

Check at the red wire going to the output transformer, that should be the same. I don't have one of those Bias Probe gizmos (I use output transformer shunt method to measure bias) so I don't know what goes on with them. If you've got full 508 volts (give or take a few) on the red OT wire, and both power tubes give the same reading with your bias gizmo, then I would guess there's just something odd about the way plate voltage is being measured there.

[stoneattic]

I'm reading 459VDC at the red wire on the OT so the 453VDC I was getting with the bias probe seems legit. I wonder were I'm losing 40+VDC?

[nashvillebill]

Are the B+ power supply filter caps original or have you replaced them?

I had a similar problem--but much worse-- with a Classic VTX I just bought cheap. The B+ was like 200 volts too low. Turns out one of the filter caps had dried out. I replaced them, didn't do anything else, and B+ came right up to 500 volts. (The bad cap was supposed to be 100 mfd, it measured around 1 or 2 mfd...)

[stoneattic]

They're the originals as far as I know. 100mfd on the Triumph as well. I found your thread on the VTX and it sounds like the first thing to try for sure.

I'll take you advice and pull it apart and measure them dimensionally. There seems to be a pretty wide range of physical sizes and shapes available and not a lot of room in the T60.

I've got a Boss GE-7 EQ (with the Monte Allums mod to get rid of the noise) in the loop with the lows boosted, the mids dropped and the highs about middle. Kind of a crooked smile. I'm pretty happy with the way it sounds like that. I'd like to mod it to sound like that without the EQ but I'll worry about getting B+ up first.

One thing I've noticed is that the Scorpion speaker seems very directional, at least compared to my DC-2 and it's Vintage Black Shadow. The T60 sounds great on axis, but just a few feet off and it losses it's chunk.

Thanks again.

[stoneattic]

Still messing with this thing. While measuring the existing caps to replace all the electrolytics, I noticed a few things:

1. Mine also lacks R98 and C63.

2. The schematic calls C3 as 22uF/25V but mine has a .47uF/50V.

I believe that this lower C3 value would be hurting the bass response. I plan on putting the called for 22uF in there. Any thoughts about this? Am I correct in believing that increasing the the V1B cathode cap would improve the bass?

[nashvillebill]

Normally it should, but V2B has a .47 on it also.

[stoneattic]

Does yours have the.47uF like mine or the 22uF as called out on the schematic?

I'm a beginner at this and still trying to understand. It seems to me that once you cut off the highs in one stage they would be gone for the rest of the stages, but obviously this isn't the case or they would use the same value for all cathode caps.

My amp is too bright. The clean channel only sounds good with the high eq set to almost zero and the mid pretty low. The crunch and ultra channels need an EQ in the loop with the mids pulled way down and the highs pulled down some to make it bearable.

[stoneattic]

BTW Bill, what caps did you use to replace your filter caps? I've been looking on Mouser's and Newark's site and the only radial caps of 100uF/400V that have a similar height and diameter have a 20% tolerance. Is that adequate?

[nashvillebill]

I think mine had the 22 mfd everywhere except the .47 on V2B. I got my caps from Digkey, I don't remember if they were Nichicons or Panasonic (I'm thinking Panasonic but its been too long). The 20% tolerance is fine, or go higher voltage.

Try to get the high-temperature versions. The inside of this amp gets very hot, there's not enough ventilation. The hot melt glue I used to secure the cap job...melted.

My combo has little ventilation grills on the side of the wooden cab. But they don't actually vent into the chassis, so i don't think they're much use. I am going to take them out and cut some holes in the top of the amp and put the grills on top of the amp, so there will be some ventilation inside the chassis. Then on the side of the cab, where the grills were, I'm going to enlarge the holes and put a couple of handles (the recessed handles some PA speakers have).

[Enzo]

Just checking in, I haven't followed the thread. Let me know if I missed something related to this detail.

Looking at the schematic, your main B+ at C42 is about 500v. You have about 460 on the output plates. You wonder where the 40v went.

Unlike most amps, if the schematic is correct, note that the plates come off AFTER that 400 ohm resistor. On most PV amps that 400 ohms is between plate and screen nodes. The schematic says the 400 ohms drops 8 volts, that means the entire amp is only drawing 20ma of B+. I have my doubts. However, if 100ma were flowing through that 400 ohms, then voila, 40 volts.

[nashvillebill]

Schematic isn't correct, plates are before the 400 ohm resistor. There's a couple of minor mistakes on the schematic.

The power supply board component layout drawing is correct, but they don't label the terminals. After B+ is rectified, the trace goes past the filter caps, then a couple of jumpers carries B+ over to the upper left part of the board. The red wire to the OT is soldered to that terminal.

The screen voltage comes off of the B+ trace by the filter caps, the terminal doesn't show up on the drawing. A yellow wire carries it from the terminal to the 400 ohm resistor which is mounted above the standby switch. Another yellow wire returns screen voltage to the PS board, where it comes in on a terminal on the lower, middle section of the board. A short trace then carries screen voltage to a Molex connector which goes to/from the standby switch.

And besides, if the B+ only carried 20 mA, the amp could only output 10 watts at a 500 volt B+....

[rsomera]

Another Peavey Triumph 60 question.

Hello, I've gotten a lot of good info from this forum, this is my first question. I bought a triumph 60 in good working condition. Original tubes, fairly good shape. After checking this forum I thought I'd try a couple of the mods. First stop was the jumper mod. When I opened it up I found that it looks like someone already modded it but in a way that I haven't found anywhere. It looks like they removed the resistor marked with a B in the pic and added a device. It's a little white rectangle with two leads, marked A in the pic. It's leads connect to the adjacent jumpers. It reads "CFP 005G, 250V TI". Any ideas on what this is? Google searches on the text are useless. Should I mess with removing it and replacing the original resistor? Any and all help would be greatly appreciated. My skills are average. Sorry for the fuzzy pic.

[tedmich]

if the pots in your picture are "pres"/ "high" / "mid" / "low" (L to R) from my (fuzzy) board layout from Schem Heaven they seem to have replaced capacitor C62 with one rated at 1/4 the voltage Peavey saw fit to use (5nF/1000v) Thats if the capacitor in a line from the removed piece is 15nF C7....

I'd pop a nice ceramic (Mouser 581-5SR502MEFCA $0.28) or poly cap (Mouser 871-B32632A1472K10 big!) rated to 1kV back in there.