FX Loop trouble

Hi,

Im having some problems too with my effect loops.
I am using 2 amps and both have the same problem.
Marshall Mosfet 100 Reverb & Hughes & Kettner Attax 80 Vintage Series.

At first there everything was fine. Then I started using the effect loop. Still nothing was wrong. Untill I unplugged the effect loop and started playing again. My sound was gone! Then it came back with lots of crackles and volume changes (drops). After playing a while it was stable again (or not?!?!). [U]aaarrggg!![/U]

If I use my effect loop again with a pedal, everything is fine again. What I do now when I dont use my effect loop is; I connect a cable from to Send to Return. Then it works okay. But this is not the correct way!

I sent my Marshall to a tech once, but he couldnt fix it. Someone told me once that it could be the jacks that are made of bad quality. maybe..
Does anybody know what the problem might be?

please HELP.
tanx

greets,
Ravian

That same thing is happening with both of your amps?

Exactly what effect did you run through the effects loop when the problems began?

Hi,

I used a few effect. Sometimes together, but most of the time I just use one.
The last effect I used was an EQ on my Hughes & Kettner. The other effects I use are a Delay and a Flanger.

I remember I had this problem with my Marshall before I began using the effect loop.

Greetz,
Ravian

If you are sure that it's not a short in your guitar or cables, ( and it doesn't sound like it is because it's fine with the effects loop active ) then my best over the internet, can't see it, guess is that it's a switching jack in the effect loop, probably the send jack, you need to take it to a good shop, strangest part of this is that both amps are doing it, you must have some bad mojo working,,,,,,,.........................

That is strange that's it's happening with both amps. I'd be getting those amps to a good repair man. It's got to be something in the effects loop or the pre-amp section (probably the effects loop like pstring said). If you have a pre-amp, such as a POD, try plugging into the pre-amp, then plug the pre-amp into the return of your effects loop. Nothing will be plugged into the send of the effects loop. This will bypass most amp's built in pre-amp (if the eq controls don't work when hooked up this way, the amp's pre-amp is being bypassed). Just a way to check to see if the problem is in the pre-amp section.