[amdan]

Hi - I understand that when bridged, the 4B3 outputs 900 watts vs the 7B3's 600 watts. I assume there is some advantage in using a couple of 7B3s rather than two bridged 4B3s. What is the advantage? Also, how big a difference is there? I already own a 4B and it would be cheaper for me to get another rather than replace with two 7Bs.
Thanks in advance.

[zeeman]

Stereo amps like the 4B lose damping factor and low impedance stability when you bridge them.  Bridging is a relic of pro use where the techs would need to adjust the # of channels based on the venue, so having bridgeable amps made sense.  A pair of 7B's is a far better option at the same price as 2 4B's.

[Markwatkiss]

7B's would be the way to go.

[OldAudioGuy]

I just made this exact upgrade from 1x 4BSST to 2X 7B3.  Very happy with the $ spent to do so.  If you've got current hungry speakers that are inefficient / hard to drive, its well worth going to the 7B mono's, IMHO.

Brent