Resurrected Peavey Triumph 60

[nashvillebill]

I don't have much experience with Celestion speakers--I think i had a 4x12 cab with them years ago...But I suspect the Scorpion is voiced a little bit like the Celestions with strong mids so you may not hear a big difference.

If that particular Celestion is designed for a closed 4x12 cab, it would not be good for an open-back application, it needs the mechanical damping of the closed cab.

Before changing speakers, I'd do the diode bypass mod, then also cut the jumper wire on the control board to enable the EQ controls to work even on the crunch/gain channels. The clipped jumper is visible on this picture. From left to right, you see the input jacks, the 5 gain controls, the bright switch, then the low tone pot. See where the metal pieces are that holds the body of the Low pot to the PC board? Immediately behind the right side piece you can see the clipped jumper, its just to the left of the white box capacitor.

[KrisKross]

Peavey Triumph 60

That's brilliant, thanks very much for the response. So I don;t screw this up I've attached a mark-up of what I think you mean - are you referring to the untouched jumper circled in red and marked 'A', or what looks like a cut jumper circled in blue and marked 'B'.

Since this is probably a photo of your already moded amp I'm assuming you mean the (ex-)jumper circled in blue?

Also, whilst we're on this you couldn't ident for me the CR1 & CR2 diodes and how I bypass them?

[nashvillebill]

The cut jumper marked "B".

I'll have to go through my pictures for the diode jumpers, that's on the preamp tube board.

[nashvillebill]

Okay, here's the preamp tube board. Look at the bottom of the picture where you see the printing on the board itself, labelled Triumph Preamp Bd 98850810 then the date 031987. Immediately above the date code there's a few traces running left to right. Then you will see the two jumpers running up and down that were put across the diodes. (Sorry I'm at work and don't have Photoshop to draw an arrow.)

Both the EQ jumper mod and the diode bypass mod here can be done with the boards still in the amp.

[KrisKross]

Triumph 60

That's great. Thank you. I look forward to further post.
Have a great weekend otherwise.

[nashvillebill]

Count over from the standoff just to the upper right of the date code, they're the 3rd and 4th solder pads going to the left of the standoff. (What looks like a jumper about an inch to left of these two, is actually just a scratch on the conformal coating on the board)

[Gtr_tech]

SCorpions are sort of an EV knock off. I don't care for them.....pretty cardboard sounding. Perfect match for wafer base Sovwreck WGCs. CArdboard box filled with cardboard......

[Patrick Lau]

The GT-Fender 5881 (Blue) got no problems so far, the early breakup and lower output made the Triumph sounds even better in low volume!
Did the 1st part of Recap, changed the caps on the power board, the sounds fuller and more headroom on the high frequency, the control board and preamp board's term tonight

Tonight's work included adding a fan! If I remembered correctly, Enzo(!) once mentioned the electric plug was there same as the 120Combo. Found it and guess It won't be that difficult to do so. Let's see the result!

Few things on this first Amp Project,
1. Power Amp Input
2. Tone Control Mod (Change the Bass' response! and decided if i still wanna add Channel EQ control?)
3. Channel LED - I guess I can wire it and have the power supply form the footswitch. I wired the footswtach and using some new brighter LED, it's fine but TOO bright now, check the current draw and guess it won't hurt even add 10s more... check the footswtich as per attach

it's now time to start gathering info for the next mod project, another Peavey, Classic VTX, another NOS, with the original shipping slips and "US duty not paid seal when I open it!!!

[bfglp]

Heater voltages on remaing preamp tubes--only 4 volts DC. WTF? Let's look at the schematic, yep they rectify the heater voltage to DC for the first three gain stages.Let's put the scope on the heater supply for those 3 tubes--gee, that's a terrible looking sawtooth--and it's only 60 hz.

No diodes handy, but I had a couple of bridge rectifiers. I mounted a 25A bridge rectifier on the side of the PC board and ran a few inches of jumper wires. Bingo, heater voltage now close to 6 volts, 120 hz with not a lot of ripple. Oh, and the power tubes now almost even on current draw.

Plug 'er in...hiss noticeably improved. Volume and gain now fine. I suppose the low heater voltage meant it was taking a while for the tubes to heat up enough to work.

my gain channels dont work even when the amp is hot. how about some pictures/info of what you did to increse voltage on the preamp tubes?

[nashvillebill]

Unfortunately I won't have an opportunity to open the amp up for more pictures for a while, sorry!!! Too much stuff going on!

I'm not sure how advise you on troubleshooting this since I don't know your electronic skills or background, and I'm not sure what you mean by "your gain channels don't work". Does sound come through them, but no volume, or do you mean that the amp won't switch from the normal gain channel into the gain channels?

i'll try to help if you can describe more of what's going on and what you have tried so far.

[bfglp]

i have normal gain chanel but crunch and ultra dont work or will work intermitenly. i loose all sound in ultra mode sometimes i get like 5% volume on the crunch chanel. if i hit the standby off/on i can get them to come on, this makes me think it has to do with power to the preamp tubes.

i dont have much trouble shooting experience but i know how to work safely around electrical components and have excellent soldering skills.

[nashvillebill]

Ok, have you downloaded the schematics at Schematic Heaven - FREE Amp Schematics Tube Amp Schematics Valve Amp Schematics Effect Schematics Effect Pedal Schematics Guitar Amp Schematics Bass Amp Schematics Fender Amp Schematics Marshall Amp Schematics Gibson Amp Schematics Vox Amp Schematics ???

They're in the post-70's section.

[bfglp]

yea got it, thats a great site.

[nashvillebill]

Okay, do you have a pretty decent digital multimeter (DMM)?

If so, look at the schematic, and find the power supply section. Look for caps C49 and C50. These are on the rectified DC circuit that supplies the heaters on V1, V2, and V3. Look on the preamp board layout that shows component placement and follow the + and - traces coming from C49 and C50 over to the pins on the sockets that hold tubes V1, V2, and V3.

Now remove the amp from the chassis. Plug a dummy load (preferably, though the speaker would work) into the speaker jack and plug in the remote footswitch. Plug the amp into the wall and turn it on. Be careful now, the amp will contain LETHAL voltages/current. Use your meter to measure the DC voltage on the heater connections on the preamp board for each tube V1, V2, and V3. This voltage should be around 6 VDC. If it is, you do NOT have a problem with the heater supply circuit. (You may still have a loose tube socket, or bad solder joint on the socket leads, or a bad tube...or the problem is NOT with the heaters at all).

If you do NOT have 6 VDC, then go to V4 and V5. See if you have about 6 volts AC on the heaters on those two tubes. If not, start tracing across the multiconductor wire back to find out where you are losing the connection.

If you're having difficulty figuring out what I'm describing, then perhaps its best for a shop to tackle this instead. I'm not trying to talk down to you--I'm certainly no expert, but this is not the amp for a beginner to start learning on. The stacked boards make troubleshooting much more difficult, it is a fairly complicated amp, and it would be quite easy to make a mistake that either a) fries the amp or b) fries you .

[bfglp]

Okay, do you have a pretty decent digital multimeter (DMM)?

I'm not trying to talk down to you--I'm certainly no expert, but this is not the amp for a beginner to start learning on. The stacked boards make troubleshooting much more difficult, it is a fairly complicated amp, and it would be quite easy to make a mistake that either a) fries the amp or b) fries you .

yes i have a nice fluke DMM.

the stacked boards do pose quite a challenge. im not going to open up the amp untill early next week. so dont that i lit myself up if i dont post for a few days, i have other working amps so there is no presssure to fix this one. ill scan the boards with my magnifying lense for loose/poorley soldered joints, than isolate and secure the boards before putting a load on the amp.