peavey triumph 60 lost gain channels

[bfglp]

the clean channel sounds great as always but when i bypass to ultra it looses most of its signal. the low gain is even weaker.

any ideas???

[Jazz P Bass]

Triumph 60 schematic

Here is the T 60 schematic.
Is "Crunch" also faulty.
Same circuit as "Ultra", different gain pot.
Try changing out V1 & V2.

[bfglp]

yes the crunch channel is missing alltogether.

i put in new ax7's with no change.
i also tested the at7 in a stand alone preamp, and it had alot of static.

[Jazz P Bass]

Foot Switch

I believe the Ultra channel can only be accessed by the footswitch.
Are you using the one from Peavey?
Use a meter (on AC Volts) or a scope & look at the signal coming out of the effects send.
If it is good on the clean channel & bad on the ultra channel then
the problem lies between Sw 1, R12, 220K & the effects send jack.
Sounds like you may have a bad relay. (S1, S2, S4 )

[bfglp]

im using the OE peavey footswitch.

i have signal on effects out through the clean channel but not on ultra or crunch.

where can i buy parts for this amp?

[Jazz P Bass]

Peavey Parts

You could try Peavey. They have some great people working there.

[Enzo]

Apply a test signal - I use music from the shop stereo. We don't really care if the signal is realistic, since we are searching for where it just goes away. Set the amp up for the missing channel, then trace the signal stage by stage through the amp, looking for where the signal disappears. Ther are only three triodes in the channel, half of V1 and both halves of V2.

yes Peavey will sell you any parts, but things like caps and resistors are generic, get them from any parts seller.

[bfglp]

thank for all the help. it turned out to be loose wires in the foot pedal recipectical. hardwiring this connection should be added to the mod list for this amp, its really useless without the pedal anyway.

[pinevalley]

FYI it appears the ultra channel is default for the amp with no footswitch plugged in. Need the switch to get crunch. So also the clean channel is not accessible without the bypass on the footswitch.

[bfglp]

my amp is acting up again, so it wasnt the pedal plugin.

i tryed it with no pedal and in the default mode the signal breaks up and gets weak.

[nashvillebill]

I'm playing with one of these amps myself and have somewhat similar problems. I suspect several possible problem areas on mine:

1) The amp uses Molex connectors which have the wires pressed into the connector (Insulation Displacement) rather than the wires being stripped and crimped onto the connector. This is poor.
2) The switching relays may be failing
3) Any of the coupling caps may be failing
4) The tube sockets may be loose

There could be a cracked solder joint but I've reflowed most of them...

When the amp works right, it sounds great. I intend on removing the Molex connectors entirely and soldering the wires directly, replacing all the relays, replacing the caps, and replacing the sockets. I may even go with metal film resistors to see if i can reduce some of the background "hiss".

[Xenrelic]

Check C16 & C13, these went out on a Triumph 60 that I was repairing and the Crunch/Ultra Channels became like clean channels. There were some other issues that caused the caps to go bad such as bad filter caps and a few bad resistors. All of the 1/4 watt carbon film resistors should really be 1/2 watt at least and the blue 1watt resistors should be 2 watt metal oxide. I prefer the metal film over the carbon film to reduce noise in high gain amps.

[bfglp]

problem solved! it was the 12at7 tube. i pulled the jj tesla tube that was in there and tryed 2 electro harmonix tubes with poor results then i put in a Mesa tube and no more issues.