Tube Amp suddenly became very quiet

[Metalmann13]

I have an all tube peavey 6505+amp head and recently I noticed it became quiet. I was playing guitar with everything seeming normal and I rolled the guitar volume all the way down and took a 3 minute break, but when I came back to play the amp's distortion channel only had one low volume and the clean had no volume at all. I tried turning the volume up and down on both channels, but neither of them changed volume. It is not a guitar issue because I tried multiple guitars on the amp with the same results. Could it be the power tubes?
Question: What steps can I take to find the issue? Or is there a known solve to this issue?

 

[Inearthed]

With any volume issues with Peavey’s I always work a cable in and out of the effects loop a couple times as a starting measure to troubleshoot it. Sometimes these jacks get a bit of build up or oxidization (or something) and result in weird signal issues.. With the amp off, plug in a normal guitar cable into the effects loop send and return, unplug the cable and then plug it back in again a number of times... then remove the effects loop cables and power the amp back on - any change?

After that my go to would be swapping preamp tubes.

 

[MetalHeadMike]

^^^
This + try a new instrument cables.

Preamp tubes caused a similar issue with one of my amps. No clean but the gain ch was fine and then after a year of no clean whatsoever the gain ch started acting up. I never play clean so I never bothered troubleshooting but when I lost the gain ch well... I Replaced preamp tubes 1 by 1 until I found the bad one and now all is good.

 

[Metalmann13]

With any volume issues with Peavey’s I always work a cable in and out of the effects loop a couple times as a starting measure to troubleshoot it. Sometimes these jacks get a bit of build up or oxidization (or something) and result in weird signal issues.. With the amp off, plug in a normal guitar cable into the effects loop send and return, unplug the cable and then plug it back in again a number of times... then remove the effects loop cables and power the amp back on - any change?

After that my go to would be swapping preamp tubes.

This method worked! I plugged the cable in and out of the loop and it brought my amp back to it's original state. Thanks.

 

[Inearthed]

With any volume issues with Peavey’s I always work a cable in and out of the effects loop a couple times as a starting measure to troubleshoot it. Sometimes these jacks get a bit of build up or oxidization (or something) and result in weird signal issues.. With the amp off, plug in a normal guitar cable into the effects loop send and return, unplug the cable and then plug it back in again a number of times... then remove the effects loop cables and power the amp back on - any change?

After that my go to would be swapping preamp tubes.

This method worked! I plugged the cable in and out of the loop and it brought my amp back to it's original state. Thanks.

I’ve seen this happen to Peavey’s new and old - not sure what the deal is with their jacks but it is my go to thing to try first.