I read an interesting article about bi-amping in a recent issue of HiFi+ magazine. It basically said to use the same amp to bi-amp a specific speaker. In other words it was saying that if you had a stereo amp use the L and R channel from that amp to bi-amp your speaker. It says that level mathcing is extrememly difficult acros two different amps. The article made sense to me.
If you are goign to get a 7125 then use that amp to bi-amp you mains. You would use your HK as a preamp. You could use the 7125 to bi-amp your front speakers (That would use 4 channels of the amp). That would leave you with 3 remaining channels (For center, and surrounds).
Obviously the issue with this is you now have an extra Parasound A23 amp. If you like the A23 just get another one of those and use one of each to bi-amp your mains.
Good Luck. Personally Bi-amping is something that I have always wanted to try, but never gotten around to doing it.
Regards,
Charlie
_________________________
Charlie,
Outlaw 970, B&K AV5000, Paradigm Ref 20 and CC (V1), Martin Logan Dynamo, Sony 42" RPTV, Toshiba HD-A1