Mutliple amps effects loops, one pedalboard.

Q & A for building and interfacing your rack gear with Ground Control Pro and GCX-based systems.
nyteowl
Posts: 1375
Joined: Mon Jan 25, 2010 8:53 am

Re: Mutliple amps effects loops, one pedalboard.

Post by nyteowl » Tue Jun 11, 2013 9:54 am

rp108 wrote:I would like to be able to do that. I would like to switch between them with the guitar and effects switching to each amp.
Okay, here's what you're up against.

First and foremost, each FX loop must be isolated from the other two. The last thing you want to do is cross the signals where the FX Send from any amp goes to the pedal board and inadvertently gets routed back to the FX Return of a different amp. Lots of potential there to damage your gear and it also means you absolutely cannot run any two amps simultaneously.

Second, the ability to choose between 3 amps - maybe more in the future - on the fly and have the effects move from one amp's FX loop to the next seamlessly will need to be accomplished with a single button push in order to avoid crossing signals. This means that you're going to have to configure each amp as a preset on your GCPro, so the appropriate loops will activate and deactivate simultaneously each time you select a preset.

Do you also need to do amp channel switching?
I am not affiliated with Voodoo Lab in any way, but enjoy sharing what little MIDI and signal routing knowledge I've picked up over the years. If you find my assistance helpful, please pay it forward.

nyteowl
Posts: 1375
Joined: Mon Jan 25, 2010 8:53 am

Re: Mutliple amps effects loops, one pedalboard.

Post by nyteowl » Wed Jun 12, 2013 6:31 am

Well, I thought I had it figured out yesterday afternoon, but then I realized last night what I'd posted wasn't going to work. I do have it properly sussed out now, though, and here's what I came up with.

First we'll deal with the guitar signal:


Guitar -> Loop 1 In
Loop 1 Out -> Amp 1
Loop 1 Send -> Loop 2 In
Loop 2 Out -> Amp 2
Loop 2 Send -> Amp 3


Next we'll deal with the amplifiers respective FX Loops:


Amp 1 FX Send -> Loop 6 In
Loop 6 Out -> Amp 1 FX Return
Amp 2 FX Send -> Loop 7 In
Loop 7 Out -> Amp 2 FX Return
Amp 3 FX Send -> Loop 8 In
Loop 8 Out -> Amp 3 FX Return


Now we'll add the Pedal Board:


Loop 6 Send -> Loop 3 In
Loop 7 Send -> Loop 3 Return
Loop 3 Out -> Loop 4 In
Loop 8 Send -> Loop 4 Return
Loop 4 Out -> Input of first device on Pedal Board

Output of last device on Pedal Board -> Loop 5 In
Loop 5 Out -> Loop 6 Return
Loop 5 Send -> GCX Front Panel Guitar In
GCX Rear Panel Guitar Out -> Loop 7 Return
GCX Rear Panel Feed Thru -> Loop 8 Return


We're using the front and rear panel Guitar In, Out and Feed Thru jacks to split the Pedal Board return signal. By doing this we eliminate the need for a second GCX.

Last but not least, we program 3 Presets:

Preset 1 will have only Loop 6 active.

Your guitar signal will go out of Loop 1 to Amp 1 and Loop 6 will send the guitar signal - via the amp's FX Loop - to Loop 3, where it will pass thru Loop 3 to Loop 4 and on to the pedal board via the Loop 4 Out. The processed signal will be returned to the Loop 5 In and passed thru Loop 5 Out to the Loop 6 Return and from the Loop 6 Out to Amp 1's FX Return.

Preset 2 will have Loops 1, 3, 5 and 7 active.

Your guitar signal will go out of Loop 1 Send to Loop 2 In and from the Loop 2 Out to Amp 2. Loop 7 will send the guitar signal - via Amp 2's FX Loop - to the Loop 3 Return, where it will pass thru Loop 3 to Loop 4 and on to the pedal board via the Loop 4 Out. The processed signal will be returned to the Loop 5 In, passed thru the Loop 5 Send to the GCX Front Panel Guitar In, from the GCX Rear Panel Guitar Out to the Loop 7 Return, and from the Loop 7 Out to Amp 2's FX Return.


Preset 3 will have Loops 1, 2, 4 and 8 active.

Your guitar signal will go out of Loop 1 Send to Loop 2 In and from the Loop 2 Send to Amp 3. Loop 8 will send the guitar signal - via Amp 3's FX Loop - to the Loop 4 Return and then on to the pedal board via the Loop 4 Out. The processed signal will be returned to the Loop 5 In, passed thru the Loop 5 Send to the GCX Front Panel Guitar In, from the GCX Rear Panel Feed Thru to the Loop 8 Return, and finally from the Loop 8 Out to Amp 3's FX Return.

Sounds complicated, but then again, what you asked for was a pretty tall order. Let us know how you make out.
I am not affiliated with Voodoo Lab in any way, but enjoy sharing what little MIDI and signal routing knowledge I've picked up over the years. If you find my assistance helpful, please pay it forward.

rp108
Posts: 20
Joined: Thu Jun 16, 2011 9:33 pm

Re: Mutliple amps effects loops, one pedalboard.

Post by rp108 » Wed Jun 12, 2013 8:08 am

Very impressive. Thanks for looking into this. The only concerns I have, well besides going cross eyed from your post, is that adding amps is not as scalable as I thought it would be. Also, this method leaves out switching effects that run in front of the amps.

I have to give it some thought but it's good to know it is possible. If I want a full fledged, scalable switching system for my needs, I think I would need at least two GCX units. If I do decide to set this up, I think I would have to contact you or someone on the phone and get support for this. Diagrams will be needed for sure and like I said, the solution needs to be scalable.

nyteowl
Posts: 1375
Joined: Mon Jan 25, 2010 8:53 am

Re: Mutliple amps effects loops, one pedalboard.

Post by nyteowl » Wed Jun 12, 2013 8:55 am

Sorry my post is making you cross-eyed, but I cannot upload diagrams from this location.

Adding additional GCX units will make this as scalable as you need it to be, so you'll be able to control however many more amps you want, as well as give you the ability to switch effects, although your second post in this thread gave me the impression you did not want to do that.

In any event, in lieu of using multiple GCX units, you may want to consider something along the lines of a Sound Sculpture Switchblade, which offers more signal routing versatility than the GCX.
I am not affiliated with Voodoo Lab in any way, but enjoy sharing what little MIDI and signal routing knowledge I've picked up over the years. If you find my assistance helpful, please pay it forward.

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