TOPIC:

Is there any reason why I couldn't use an 88 with an AV receiver which has pre outs and Multi Channel Inputs. ( Pre outs to 88 then back to the Multi Channel Inputs )

You would need to check the manual for your receiver, but I suspect that won't work as the MC input is an input, not between the preamp and the power amps. (In other words, you will create a feedback loop.)

To put it another way, if you just connect from your preouts to your MC inputs with RCA cables, will it work? (I suspect not.)

Older receivers used to have separate power amps inputs and jumpers from the pre outs, like this (to the left):

nadelectronics.com/img/img.php?061101111...x-T754_rear.jpg/1200

@ Grumpy@72
We'd have similar feedback than John here but best that you contact the tech support of that AV receiver to double confirm.
These inputs are typically not meant to be used as an insert I'm afraid. I'm guessing that you were thinking to do this for using the amplifier inside the AVR?

Devteam

Yes I was thinking that following a severe case of upgradeitus but think I'll stick with my current processor for a while until I can afford to upgrade that.

Well, if your scenario is compatible with the nanoAVR DL then that would be the way to go for less.