Running Two Amps With Stereo Effects?

[nogalian]

I have been trying to run two amps, #1 Mark IV, #2 Mark III, using a GCX Switcher and GCP board to control an effects unit, TC Electronics GForce, in the loops of both amps. The idea was to enjoy stereo effects with the different sonic qualities of both amps. Perhaps one amp clean and one dirty, maybe one dirty and one nasty, whatever. The problem is when the loops are engaged (via the GCX) the tone from one amp "bleeds thru" to the other. So when L is Clean and R is Crunch, Crunch comes thru and contaminates Clean tone on L or visa versa. When both loops are on and the FX are bypassed on FX unit no bleed thru. FX unit is set up for stereo output. Signal goes from the guitar to loop 1 (Pledal) to a y to feed loops 4 and 5 (on/off for the amps) and out to the amps 4 for L and and 5 for R. The send and return of each amp each go to one side of the gforce and back to separate loops to control L loop and R loop.
Any comments or ideas would be GREATLY appreciated!!
Thanks!!

 

[Rob Lockwood]

I'm sure that the problem is within the G force. I dont know that unit well but on another processor I had you actually had to change something in the set up to get true stereo operation where both L and R channels operate totally independantly. My guess is that its not so much accidental bleed through but that in the G Force the L and R inputs are being mixed at some point in the chain so that what comes out of both L and R outputs is a mix of clean and dirty amps. There may be a global parameter or a mix parameter in one of the fx blocks that you need to change. Sounds like you need to get stuck into the G force manual, or maybe also try a TC support forum etc to find out how to keep the channels seperate.

 

[capnlee]

I use a DOD stereo chorus pedal. I don't use the effects loop. I go with the guitar directly into the pedal, and from the stero pedal outputs directly into the instrument input on each amp. It's stupid simple and works to great effect.

 

[nogalian]

Thanks for your comments!
Been looking for this answer for a while. I think I am the only person on the planet with this issue!! :lol:
Thanks.

 

[SonicProvocateur]

Double Edit: Are you bridging the signals coming in and out of the amp? I know you are sending it out with the Left/Right output jack, but does the G-Force have 2 separate stereo inputs or just the one line in? I'm wondering if this could be the true culprit of trying to run one amp clean and the other dirty.

To have a truly stereo rig you need 2 independent effects loops and the ability to control the mix between the two so you can pan the left and right channel 100%. If one amp is dirty and the other is clean and you are sending one clean and one overdriven signal back into the return loop, then the once clean signal is going to be slightly overdriven on its next send path in stereo.

 

[nogalian]

Right. What's weird is the gforce has like 200+ factory presets with several set up FOR a stereo image. They work just as bad as the ones I've made myself! I regret seling my eclipse. The end goal is to run two MarkIII's in stereo. Just bought a blue stripe and can't wait to get it!!

 

[Rob Lockwood]

Good point above mentioning panning of the stereo image. I know that the GForce has stereo L & R inputs as well as outputs so that should be ok, but many stereo effects have a pan parameter to control how much each the effected signal from each input is mixed between L & R outputs. I know that all the Delays in my GMajor had a pan setting where you could mix the L & R and I think the default may have been center which would cause exactly the problem you have. When set to center the L & R are mixed 50-50 so that what comes out of the outputs is just a mix of the two inputs and there is not stereo effect. Even an effect set for stereo might not have the L & R panned hard to left and right, it is common to soften the stereo image a bit. I would suggest getting into the detail parameters of the effect you have active in the current patch and make sure that any that have a pan control are set with the left signal panned fully to the left output and right fully to right. The manuals for the processor usually have block diagrams for each effect showing how this works.

 

[MrMarkIII]

The "normal" way to run stereo would be to use the loop in one mark III. Run the send from the first amp to the effect unit. Run the LEFT out to the return of this amp, and the right OUT to the effect return of the second amp. You are only using the power section of the second amp.
Yes, I know, you're not getting one clean and one dirty amp this way, but that never works that well. It will either sound too clean, or too dirty.
It's very, very hard to get the balance correct, and one amp almost always overpowers the other.

 

[topalchohol]

Does the G-major have 2 separate send/returns? If not it will blend the 2. If it does have seperate you may have to adjust a wet/dry parameter? Good luck.

 

[nogalian]

Agreed MrMarkIII. It is tough to have a good balance without one overpowering the other. However it is pretty cool to have two distinct tones maybe one crunch and one a bit nasty with a tasty effect thrown in. It is AMAZING to me how incredibly different the tonal possibilities are between mark series amps, ie MKII, MKII, MKIV!!! To me it is like being in a B&R 31 flavors shop and having to pick only one!! Impossible!! I want three different scoops all at once
Hope I don't offend anyone but I had a MKV and was happier selling it and buying a MKIV MKIII , and a MKII. IMHO they are sooo much better sounding amps by themselves. To me The only thing better than playing my MKIII is playing with a MKIV alongside and eventually in stereo!