Using Adcom GFA-555s as monoblocks to power magnepan 3.3s in active biamp

No, there's nothing precious about the Adcoms.  I have them mostly as backups or to run stuff I'm testing.  

But yes, mostly rock.  I've been spending more time listening to my (new to me) KEF R11s.

I think I've decided not to bridge the Adcoms. 

I wonder why so many amps are bridgeable when most of the inefficient speakers are 4 ohms anyway. 

Run  some fans.

I had a Krell Ksa250  running B&w 801#3's

Got a Pair of Adcom 565 monos on loan from a steroshop.

Adcoms did very well, Sounding a Bit steely on highs but the lows were neck in neck.

The adcom will pry need to be checked for DC offset and or caps replaced.

Fine amps for the money

Which do y'all think will sound better with KEF R11s:  a single Classe CA-200 or 2 Adcom GFA-555's in vertical passive biamp?

In a somewhat analogous situation, I ran a pair of Hafler DH-220s bridged into a pair of Acoustat 1+1 and RHLabs sub. I thought  it sounded fine until someone smarter than me pointed out that the amps were likely quite unstable in that configuration. So as an experiment, I switched them out of bridged mode and used only one channel of each amp to drive the speakers.

I could not believe my ears at the improvement! Even with "less" power the sound was much better, more cohesive top to the now much better bottom. Others here have explained it better than I could but the bottom line is, I have practical experience to say that bridged is NOT the way to go in a low ohm situation.

Happy Listening!

Wow, thanks.  So, another question: is there any harm in running 1 channel of each Adcom?