Effects loop issue - does yours do this?

fredster · Feb 27, 2011

Hey gang,

It doesn't sound like I'm getting a real series loop. What I mean is, if I have cables plugged into send and return but not into a processor, I would expect to hear nothing when I engage the loop. I'm pretty sure that's what happened on my LSS. But with the Mark V I still hear a small amount of the original signal, very thin and trebley, that's not affected by any of the volume knobs. It's loudest on ch.2. Does yours do this or am I broken?

Jiveman · Feb 27, 2011

I noticed a similar thing when engaging the tuner switch on my GT-6 (or turning its volume pedal all the way down) which sits in the FX loop. There is a very small small amount of signal still being passed through, which is weird. But I wonder if this is normal?

fredster · Feb 27, 2011

Hmm...If you disconnect the GT-6 but leave the cables on the amp, do you still get that small amount of signal? I think that's what I'm hearing also.

Boognoob · Feb 27, 2011

Apparently the loop is fussy with loop db levels.

But I tried My old combo, a combo of simliar age in the store, and they both were like it.

Got a new head a couple of days ago, the Loop is the last thing Ive not checked... will definitely do so tomorrow when its safe to make some racket.

Jiveman · Feb 28, 2011

fredster said:
Hmm...If you disconnect the GT-6 but leave the cables on the amp, do you still get that small amount of signal? I think that's what I'm hearing also.

Haven't tried that, but I believe I would get the same result as you. In theory, pressing the tuner button on the gt-6 puts it in "mute" mode (if configured that way) and the GT shouldn't be outputting ANY signal whatsoever. So the signal coming out of the amp into the GT should not be coming back. And yet I hear a little bit, like you're describing.

It's not enough to really bother me, personally, and I don't think it really messes with the "serial" nature of the FX loop, as its volume level is so low. But, whether this SHOULD or SHOULD NOT be happening at all, to begin with, is another question, and one that I don't have an answer to.

fredster · Feb 28, 2011

Thanks man, I am finding that this is indeed as designed. I have no idea why - the definition of a series loop means that all the signal goes through it. It's bothersome because that residual signal is mixing with dry signal in the processor only slightly delayed by a small amount. That makes it sound out of phase or filtered in some way. I read that turning up the channel masters can help - I'll give that a try. Thanks for your thoughts guys!

Fred

screamingdaisy · Feb 28, 2011

I found the same thing. I think Mesa did it so that the amp doesn't pop when the effects loop is switched in and out. It's only really an issue at very low volume levels. Once the master output is turned back up the phase effect disappears.