One Amp - Two Preamps Routing & Pan Question

[Genghis]

Hi everyone. I'm running a 5150 III 50w head with the FX8, and I'm planning on incorporating one of those new Diezel VH4 pedals into my setup for an alternate metal tone. (Mostly for a second flavor when I double track rhythm guitars.) This pedal can be run either into the front of the amp, or into the power amp input, just like a preamp. I'd like to run it as a preamp, but that could change once the pedal arrives and I see what really sounds best.

My plan is to use the FX8 and a strategically placed pan control to pan between the 5150 preamp and the VH4 pedal, and I think I've got the routing figured out on paper. My main question is, will I need any additional blocks in the FX8 to accomplish this besides this one additional pan control? I'm thinking that the last block of my pre signal would be a pan block, routing the signal into which preamp to use, and that should do it, but I wanted to check with the experts and see if I need to do anything special on the signal coming back into the FX8. Do I need any additional blocks in the Post section due to the split preamps? I'll probably run the power amp of the 5150 in mono, although I have experimented with stereo FX using the power amp in on my Katana for another channel.

Thanks!

 

[Genghis]

So, I dug out my Wampler Triple Wreck and figured this out last night. It took awhile, but with some info I gleaned from some other posts about using dual amps and a little trial and error I got it. It seems you need to have the pan block on the return side, and if you only use one power amp I think I had to set it to merge the left and right signal on output 2. Otherwise the pan will toggle between two power amps as well, which is not what I'm looking for.