Voodoo Lab

I have a Digitech GSP 2101 Artist Pro, a Digitech Valve FX, a Digitech GSP 1101 and a Rocktron Voodu Valve. I'm using a Peavey 50/50 stereo, tube power amp. I'd like to use a single GCX unit to select which preamp is used, while running everything in full stereo. I've come up with a couple different ways to do this as a mono rig, but I cannot seem to figure out how to properly set this up as a stereo rig. I don't need to blend the preamps at all, simply select between them.

Most diagrams show preamps in mono and effects in stereo. I understand those, but they don't translate to these all-in-one stereo units. Unlike the stereo effects boxes, all of these units only have 1 input, but 2 outputs (whereas the FX only boxes have 2 of each).

Currently I'm doing the following:

Guitar -> GCX Guitar In
GCX Guitar Out -> Loop 1 In
Loop 1 Send -> GSP 2101
GSP 2101 Left Out -> Loop 1 Return
Loop 1 Out -> Loop 2 In

... repeat for other 3 preamps with Loop 4 out going to Power Amp Left Input

GSP 2101 Right Out -> Loop 5 Return
Loop 5 Out -> Loop 6 In

... repeat for other 3 preamps with Loop 8 out going to Power Amp Right Input

I did try using the GCX Thru to the input of Loop 5 as well

When I do this I get stereo output only from the last preamp in the circuit and I get a ton of noise/hum.

If I went the route of 2 Y-cables from both the GCX Guitar Out and the GCX Thru to the input of all 4 preamps, I understand how to A/B them with a single loop... but I still don't get how to run everything in full stereo.

Can anyone help me with this?

I 'think' I figured it out. I tested it with only 2 preamps and everything works fine in full stereo. I went with the 2 preamps A/B setup as my guide after all. The trick is, since I have 4, I need to break the signal before determining what goes out to the power amp. So, I'm using loops 2, 4, 6 & 8 as my Y/N for L/R to power amp, while using loops 1, 5, 3 & 7 as my A/B loops to select which preamp is active.

Once I setup a couple of Y-cables to try to full the setup I'll report back, but I'm fairly confident this solves it. The trick is with this approach is I need to always make certain that either loops 2 & 6, or loops 4 & 8 are active before turning on the power amp to be sure it's seeing load.

I can't get attachments or images to work, so I'm using the 2 preamps selector approach (http://www.voodoolab.com/gcxdiagrams/04 ... werAmp.pdf) in loops 1 & 5 (for L & R respectively), then sending the out from 1 & 5 to the in of 2 & 6. Loops 2 & 6 send goes to the L & R of the power amp. Repeat for the other loops. This allows me to "kill" the signal to the power amp of what was selected in loops 1 & 5 when I want to use one of the other preamps from loops 3 & 7.

This won't display as an image, but here's a link to my diagram