Peavey 6505 mh effects loop woes

redragon

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Yes, this is a cheap, made in China amp, but I like it and it suits my needs.

However, when the effects loop is engaged using a footswitch, the guitar signal fades in and out or goes silent.

All of the cables are tested as good. When the loop switch is not engaged the pedals all work fine.

Also, when I'm not using the TRS switch which combines the reverb and effects loop, the effects loop works fine.

Any ideas? Yes, I could take this to a tech, but would prefer more troubleshooting. The amp is only worth about $400, not digging the idea on dropping $100+ on a repair.
 

Manurack

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There are several variables. It could be a loose wire that needs to be resoldered, or that one of the nuts are loose on the inputs of the FX loop. Have you tightened them recently? If they were loose, you can put a lock washer on to prevent that.
 

redragon

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There are several variables. It could be a loose wire that needs to be resoldered, or that one of the nuts are loose on the inputs of the FX loop. Have you tightened them recently? If they were loose, you can put a lock washer on to prevent that.
I'll check that. I have tries it with both a purchased TRS and one that I made from Redco parts. I am goof at making cables. Also, I made two, one for the clean/boost footswitch and one for the reverb/effect loop side. Switching them around gets the same results.

This weekend I also checked it by using a a regular TR (guitar) cable. That works, but of course it only switches the reverb.

It's a matter of figuring out what controls the effects loop via the switch. Maybe @Elric is onto something.
 

CanserDYI

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Try contact cleaner in the loop and running a clean instrument cable in the jacks a few times. You'd be surprised how many issues a soil built up fx loop can cause.
 

eaeolian

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Is the loop tube buffered?

No. It's buffered but I'm 90% it's op amps.

My suspicion here is that the jack for the footswitch needs cleaning, as mentioned above, or a cable with a soft open.
 


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