F/X Loop problems please help !!!!!!!

[WJR]

When i operate my F/X loop in my Marshall TSL amp and turn the chaneel onto lead and say have the volume anything above 6 i get nothing but harsh digital noise that overpowers the sound of the actual guitar and even cuts out the sustain about half the time it should be !!!! I run a 20ft cable into a digitech chorus and an ibanez delay and thne a 20ft cable back to the amp.

I tried putting a true bypass box on the amp andwhen activated the harshness disappears and the soudn returns to normal, just as if there was nothing plugged in to the loop.

This leads me to believe that possibly the length of cable has something to do with this problem ?

Please help ASAP, all advice will be appreciated

Will

[LoudGreg]

Could be a broken cable that your using with the effects.