Proceed AVP differences

I use one of these preamps. I've read there was a card option to allow an analog 5.1 input.

Thanks for the response. It’s definitley not an AVP2 or beyond. I’ve seen the inside of an AVP2.  The audio and video output boards of an AVP and AVP2 appear to be nearly identical. Main difference is the lower set of DAC boards and most likely the software. There may be some other slight variations.  In addition the upgraded AVP2 would typically have a new label under the unit. 

All items are are identical to a standard AVP except the extra board. It is also an earlier model than the AVP without the added board. 

Mostly curious. I’m not too concerned either way. Simply found the addition odd and would love to understand what it may be. 

Might be an AVP2 or AVP2+6.  They also made a video control card back in the day. I’d recommend comparing the inputs on the back of the unit.