I saw Steve Vai for a master class in Sydney in 2012 and although I could briefly approach his pedalboard, I did not really understand the presence of two Boss DD-7 delay pedals and two amps.
Fast forward two years and Steve Vai explains his setup in this video, which I recommend watching. It is lengthy by Youtube standards but Steve Vai is always an inspirational speaker. The bit about the stereo setup is around 25 min. On a side note, towards the beginning of the video, he gets a pretty mighty tone out of a stock Boss DS-1 but I digress.
I have summarised Steve Vai’s stereo setup in this picture (click on the picture to zoom in):
So basically the Boss CH-1 chorus is used to create a stereo image and each output of the pedal is connected to one Boss DD-7. The idea here is that you can have different delay settings for each side of the stereo image. Those settings can be wildly different or similar enough to fatten the tone. It provides a really nice stereo “wash” as the maestro puts it. Really cool idea!
In Steve Vai’s case The CH-1 is in the FX loop of the first Carvin Legacy amp, then feeds the DD-7s whose output is plugged into each return of the two amp’s FX loops. This means that only the power amp section of the second Legacy amplifier is used. See my previous post about using an effect loop for more information.
I use a Marshall JMP-1 preamp for recording direct and it happens to have a stereo effects loop, so I have recreated Steve Vai’s setup using a stereo Boss CE-3 chorus and two delay units: a Boss DD-3 and a TC Electronic Flashback X4.
From the “send” of the effect loop on the JMP-1, the signal goes into the CE-3. Each output of the CE-3 routes the signal to a different delay then the output of each delay goes into one of the “return” jacks of the JMP-1 effect loop.
The signal chain goes: guitar -> Korg Pitch Black Tuner -> Analogman modded TS9 -> Proco RAT 2 -> Marshall JMP-1 -> (in the loop) -> Boss CE-3 -> Boss DD-3 (right side) -> TC Electronic Flashback X4 (left side) -> Boss Micro-BR Recorder