Does anyone know the effect of taking the "send" from one amp's loop to the return of another amp?

Such as this rig.

My thought would be it would just use the pre in one amp and the power in the other.

Or does the signal still get to the power in the first amp? I know it bypasses the loop if theres nothing plugged into it. But does it bypass it with only the "send " jack being used. Hmmm.
These go to eleven...
well pedals use their own power when in the loop so i'd imagine the other amp would have to as well
it's sending the preamp signal from the main amp the guitar is plugged into, to the other head's fx in which bypasses it's own preamp. This way you can run 2 heads with one guitar.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Well if you want to run two or more of the same amps it works. But if it were like a Marshall and Mesa...if you ran FX out from the Marshall into the FX in on the Mesa...the Mesa would sound like the Marshall. If that makes sense...
^ exactly. Your using the Preamp signal from whatever amp your sending the signal from and the power amp of whatever amp your sending the signal to.
Hmmm, what if I run my ac30's preamp into my DSL's power amp, lol. Two completely different amps.
These go to eleven...
Your DSL would probably sound a lot like the ac30... Although now that I think about it if you had distortion running through it it may sound like ish. Distortion never sounds good through an effects loop...