Bryston 7B3 vs 4B3: Extra Cost Worthwhile?

@jfrmusic As another data point, I have one AHB2 for my Focal speakers. I like the AHB2 at this stage in my path, but it is not be for everyone. I have been considering a second AHB2 and enjoy trying different arrangements and listening for differences. I tried the AHB2 in bridged mode and vertically passively bi-amped, as well and the usual stereo configuration with the jumper, all using just one amp into one speaker. The sessions were relatively short and I don’t have golden ears, nor extensive experience. All were with a 10’ speaker cable.

I feel somewhat confident that I found the bridged mode to sound worse. This is not what I was expecting. There was less detail across the board and the bass was less controlled as compared to traditionally stereo but with one channel powering the entire speaker with the jumper. I am assuming this is due to the damping factor with the same speaker cable length. A much shorter speaker cable would improve the damping factor.

I believe the vertically biamped sounded better than the traditional connection (one channel of the amp power the entire speaker with the jumper across the speaker posts). The bass had the same impact, maybe a bit better however across the board there was more detail and clarity. I focus on detail, and don’t try to make it louder. I prefer about 75 to 85 db. I would need to listen alot more over various days and bring in friends/family to say with certainty, but these are my impressions so far, for my ears, on those days, in my room.

I would be interested to know Benchmarks thoughts on damping factor. Assuming the same 10’ cables are used, I believe the damping factor is halved, down to 85 bridged in to an 8 ohm speaker.

From Benchmark web site:

Nevertheless, it is possible that this 0.2 dB variation could be detected in a A/B or A/B/X test between two amplifiers having different damping factors (one with a damping factor of 100 and one with a much higher damping factor). If we match the amplitudes at 3 kHz, one amplifier could be almost 0.2 dB louder at 119 Hz using our example speakers.

The general rule of thumb for A/B and A/B/X tests is that levels should be matched to better than 0.1 dB. If this is not done, the level changes can be detected by many listeners.

This seems to conflict with their statements to you and does not address any issues with less bass driver control. The solution is to use a much shorter speaker cable to increase the damping factor, however, that involves additional cable cost albeit nominal if you use the BM cables.