Peavey amp clipping through effects loop?

[Diablo]

Hi, I've recently been experimenting with using a multi effects unit (Digitech RP-300a) through the effects loop of my Peavey 6505+ amp. I seem to be getting an effect that I would describe as clipping (the amp sounds as if theres some pre-delay or a brief cutting out when I strike a note/chord...also occasionally hear static or a sizzle noise). None of this happens when I use the multi effects unit in line directly into the amp, nor when I use either rhythm or lead channel separately.
Power tubes were replaced about a month or 2 ago. Havent done the preamp tubes, although I know the previous owne did them *at some point* as he gave me the old ones for spares.

Any idea whats wrong, maybe a ground or short somewhere in the effects loop?

[Paul]

Hi, I've recently been experimenting with using a multi effects unit (Digitech RP-300a) through the effects loop of my Peavey 6505+ amp. I seem to be getting an effect that I would describe as clipping (the amp sounds as if theres some pre-delay or a brief cutting out when I strike a note/chord...also occasionally hear static or a sizzle noise). None of this happens when I use the multi effects unit in line directly into the amp, nor when I use either rhythm or lead channel separately.
Power tubes were replaced about a month or 2 ago. Havent done the preamp tubes, although I know the previous owne did them *at some point* as he gave me the old ones for spares.

Any idea whats wrong, maybe a ground or short somewhere in the effects loop?

Unless there is a switch on the RP-300A, I would assume that the input is designed for instrument level signals. The fx loop in the 6505 is probably hitting it with line level. That'll make clippy noises.

[Diablo]

Thanks, the manual for the RP300a specifically states that it can be plugged into the efects return though :eek:

[flange]

Thanks, the manual for the RP300a specifically states that it can be plugged into the efects return though :eek:

But does it say it can be used in the loop ?
With some preamp type pedals you plug the guitar into the pedal
and the output of the pedal into the effects return to bypass the amps preamp.

[Paul]

But does it say it can be used in the loop ?
With some preamp type pedals you plug the guitar into the pedal
and the output of the pedal into the effects return to bypass the amps preamp.

Good call. I just scanned through the manual. In the section marked "Connections", it says:

Mono Operation
Connect your guitar to the Input of the RP300A. Connect a single mono instrument cable from the Left Output of the RP300A to the instrument input or effect return on your amplifier, to a channel input of a mixer, or to the line input of a power amp.

Sorry, Diablo. I don't think you can use it in the effect loop. You can patch the output of the pedal into the effect return on your 6505. That will probably bypass the preamp section of the 6505. I don't feel like reading any more manuals tonight.

[Diablo]

Good call. I just scanned through the manual. In the section marked "Connections", it says:

Mono Operation
Connect your guitar to the Input of the RP300A. Connect a single mono instrument cable from the Left Output of the RP300A to the instrument input or effect return on your amplifier, to a channel input of a mixer, or to the line input of a power amp.

Sorry, Diablo. I don't think you can use it in the effect loop. You can patch the output of the pedal into the effect return on your 6505. That will probably bypass the preamp section of the 6505. I don't feel like reading any more manuals tonight.

I think maybe I've confused things with terminology. I'm plugged in through the effects retrun exactly as described above...I thought that meant I was in the effects loop (even though it isnt necessarily a "loop" per se, as it would be if I was using the send outputs as well as return inputs). At any rate, the effects button on my amps switch pedal is able to engage/disengage the multi -effects unit (the reason why I'm plugged into the effects return jack instead of just going directly into the amps input on the front of the head).