Effects and effects loop question

New here so let me start by saying I'm loving my GM Deluxe 40!! Now to my questions.

I'm playing around with a looper in the fxloop and have noticed a couple things. When I add the GM effects to the clean channel and record a loop, they all disappear when I switch channels. The recorded loop is still playing but the effects are gone. I can only assume the on board effects are post preamp but pre send, is this correct?

Secondly, after I record a loop on the clean channel and then switch to the lead channel to solo, the volume of that clean loop jumps up. Not sure why this happens as the master is still in the same spot. This never happened on any other FXloop amp I've owned. Any ideas?

Additional point is I have my looper and a couple other effects in 4CM and the loop is engaged on all presets as I switch back and forth.

I’ve experienced the volume boost going from clean to lead also. I think it centers around the factory preset volume on the lead channel. You’re probably going to have to make a preset that tames the volume a bit for your switch over or reprogram the factory lead setting to be the same volume of the clean channel. The looper issue is interesting. Ive never tried my looper in the effects loop. I would have thought it would capture the onboard effects too on the loop

I’d have thought the effects would be post loop but that doesn’t seem to be the.case.

Irocdave12 wrote:I’ve experienced the volume boost going from clean to lead also. I think it centers around the factory preset volume on the lead channel. You’re probably going to have to make a preset that tames the volume a bit for your switch over or reprogram the factory lead setting to be the same volume of the clean channel. The looper issue is interesting. Ive never tried my looper in the effects loop. I would have thought it would capture the onboard effects too on the loop

I make my own presets but that really shouldn't matter if the looper in in the amp FXloop. the only thing that should affect the volume should be the master control, if that never moves, the recorded loop shouldn't change. Am I missing something here?

I suppose it’s not as simple as making sure that the sound you switch to, for example a lead guitar sound on say patch 30 has actually got the effects loop active?

I thought about this more and the effects going out makes sense. They are post loop so they don’t go through the looper and thus aren’t recorded.

Gazillion threads on fx loop and this one seems similar to my question, so here goes. TM20 I put looper at end of fx send loop after modulations and stuff, record an awesome loop, basking in the never ending glory.... then I go turn it up... Nope. The Gain for the TM20 is the preamp (clean or lead)? There’s nothing I can do to affect loop volume, it is what it is? I turned every thing down/up gain tone every knob, no affect on what the looper is playing back. (Sure looper has a wet/dry knob)

That’s cra cra, I don’t understand how a lil looper peddle is recording “volume” .., admittedly I’m playing in the 1W mode, but what if I go to 20W and really crank it? (It’s late my neighbors will kill me if I test now...) ... hmm... what if I switch from 1W to 5/20W while looper is playing! I’m not understanding what the preamp signal being sent to the fx loop is I guess... can I overdrive and clip the looper’s “recording”?

Hi Acutejam.  I have access to the TM18 schematic and that should be very similar in design to the TM20.  As far as we know they differ mainly by the voicing for slightly different tone.  So I can advise but only based on the TM18 and that should be enough.

The Fx Loop comes after ALL of the amp's controls and then goes through a fixed gain buffer before passing to the power amp.  That's how it is I'm afraid so there is nothing you can do about volume except adjust on the pedal if that is possible.  If you REALLY needed to, how about adding a controllable clean boost pedal after the looper in the Fx Loop?  That would give you some control.

At a first guess I would say yes, you could possibly overload your looper's input stages but it should be easy to set things up so you don't.  It helps if the looper has some sort of volume control before anything sensitive though that's probably not true and it would be based on the headroom of the looper's input stage(s).  However...  You have the amp's Clean and Lead Master Volume controls to adjust this.  They don't affect the tone of the preamp signal in any way, that is done via the previous controls, they only drop the signal level from the output of the preamp as you would expect.

Now, I certainly can see your problem.  It is that you want the nice fat power amp overdrive contribution in there too and you currently can't get total control over that for the looper playback signal with your proposed setup.  As I see it, other than the Boost pedal idea, there is nothing you can do about this.  (I could be wrong about that and if I am someone else may come in on this and correct me.)  Remember, the TM18 is the baby of the range, (I hesitate to say "economy" model   ), and it is a pretty simple circuit which can actually do a lot.  Even the other big brother models right up to the GM36/40 would suffer from this problem.  It's a design choice and trade off and the H&K team just made this decision.  In fairness, neither my Marshall JCM800 2210 nor my JVM210 have any volume control after the loop either so they would suffer from this too.  They do have gain after it but that is fixed so it is calculated into the signal level fed to the power amp anyway.  Is the issue not that the looper just does not play back at the same volume as it records or am I missing something in the problem?

Are there any amps you have in mind which do offer control after the loop signal returns?  I can't think of one offhand but I'm certainly no wide ranging model expert.

Anyone else out there using a looper who has a solution to this one?

Going to test overdriving the looper today, have warned the neighbors... this just fascinated me is all. Just imagine finishing a gig on looper and messing with output then fading out, can certainly do that with the looper or another pedal rather than amp. (I mean doesn’t everyone enjoy the show ending with the dude just playin around with noise? Heheheh)

My first big boy amp honestly and just surprised me but I get it. Thanks for explaining! I have been testing pedal paths and really like the mod/chorus/reverb/delay in the fx loop - hence the looper there too.

Then after I posted I saw a video on a dude putting a volume pedal in his fx send loop, that makes sense now. (Is that safe? See all these warnings about not running amp with speaker attached and so forth, how is THAT dumping volume?)

But yes, some volume dif ... with Delay in guitar line in path it sounds like perfect echo of guitar, same volume. FX loop definitely takes a scootch off volume.

What is the make and model of looper you are using? I'll have a look at its signal level.

I think you may be missing the point here. If the Fx Loop Send is putting out a signal and you don't touch any amp controls before it then that signal level through the loop remains the same no matter what follows it, (load impedance comes into this but that should be high enough for that to be true with any decently designed pedal). If you are running the amp without pedals in place then you would get a certain loudness out of the power amp following the loop. If that level changes due to anything it can't be the loop itself, it must be down to a pedal that is working within it.

If you capture that same level of loop signal with the looper and then play it back and get a different sound level it must be the looper which is dropping the volume on playback and not the Fx Loop. What has changed with the amp? The Fx Send is not altering it in any way that it wasn't before, nor is the buffer and power amp following the loop responding differently to anything. It's gain is fixed.

Fx loops are neutral things. They sometimes, (I would say should), have buffers before and after the loop in order to preserve sound levels as you insert a variety of different pedals. Sometimes they have a "fixed dB drop" switch to cope with extreme signal levels from some pedals but that isn't common and they usually have enough headroom to cope with that side of things. They can't usually make up for a drop in replay level in a pedal like yours. How could they know that the pedal has dropped the level in the first place to need to compensate correctly?

It is an inconvenience that there is no volume control after the loop but it isn't the loop itself which is dropping volume, it's the looper pedal. I would assume your looper pedal has a volume control. I've never seen one that hasn't though I haven't seen a host of them in all honesty. If it has then try adjusting that as you record. If you record at a higher level then I would guess you will get a higher level of replay but the guitar straight through as you play along should be unaffected. You then get the guitar at the same level with a higher level of replay from the looper. I could be wrong but I think you just need to find the correct balance spot as you record.

Any regular looper players help with this?