Peavey Ultra plus quiet on crunch and ultra channels

[btsdvb]

Hi there!
Recently bought a used Ultra plus which I absolutely love but unfortunately sometimes the ultra and crunch channels are really really quiet and I mean i can crank both the chan vol and the master and still talk over it. Sometimes after 5mins of being quiet it will suddenly open up and deafen me so its fairly random. The problem doesn't seem present on the clean channel which is functioning normal and is loud. Already ruled out tubes as i've tried two different sets with no difference. This happens with or without the footswitch connected although when it is connected I can often hear random single clicks, that same click you hear from the head when it changes channel but its doing it by itself but this may be a completely different issue.

This forum has been very resourceful to me in the past and im thankful for this! I've already defeated a low hum issue i had by reseating and cleaning all the ribbons on the circuit board but now im faced with my second issue.

[DrGonz78]

Hmmmm.... Clicking noise makes me think this amp has a relay that handles the channel switching. Since I don't have the schematic I am just guessing that it has a relay, and you said it clicks to switch channels. Probably has a relay then... Anyhow it might be the solder joints on the relay are bad or the relay is really dirty. I have heard of people cleaning the inside of a relay but that is much work. Mostly you need to trouble shoot the relay by resoldering the contact legs then check the amp again. It could be other issues causing this behavior but the relay needs to be checked, if it has one.

[The Dude]

+1 on relays. The fact that you seem to have random relay clicking seems to indicate that you might have cold solder on the relays. If the relay contacts were bad, it wouldn't randomly click. It would click when it's supposed to, but not switch due to faulty contacts in the relay. The random clicking tells me that the relay coil is being energized randomly- again likely an intermittent relay coil connection.

Also, a common problem with these amps is the switching jacks for the effects loop. The loop is common to all channels, but it could just be chance that the clean channel works when you try it. It's a simple enough check. Just run a cable from effects send to effects return completing the loop and see if the problem goes away.

[Jazz P Bass]

Peavey Ultra + Schematic

Here is the schematic.

Note: I reloaded the file using Chrome.

There is something up with the site!

10 minutes to download a friggin file?

WTF.

[nashvillebill]

I'm getting an Invalid Attachment error message when I try to open the schematic.

But I concur with the others, could be bad relay or relay solder joint or bad solder joint anywhere in the ultra/crunch circuit--on the tube socket, etc...

[DrGonz78]

Try this link...
PEAVEY ULTRAPLUS SCH Service Manual free download, schematics, eeprom, repair info for electronics

[btsdvb]

Cheers for all the feedback guys. It's looking quite likely to be a cold solder on the relay. I'm gonna get it looked at by a local amp tech as it's beyond my ability to repair. Thanks again! One more quick question just noticed I'm running the amps power at 240v/60hz but being in the United Kingdom shouldn't it be set to 220-230v/50hz? The guy who had it before also ran it at 240