Bryston 4BSST2

As with many bridgeable amps, the 4BSST2 does not have a maximum power rating for a 4 ohm load when operated in bridged mode, it just has a rating for an 8 ohm load in that mode. Typically the reason for that is the fact that in bridged mode each channel of the amp will "see" a load impedance equal to the speaker impedance divided by two. So a 4 ohm load would be seen as 2 ohms. Some amps will not be able to handle that kind of load at all, and others will not sound as good when doing so as when driving 4 ohms in stereo mode. I suspect that the latter applies to the 4BSST2.

And I agree with ZD that the preponderance of credible anecdotal reports is that the majority of amplifiers will not sound as good in bridged mode as in stereo mode. Probably even when driving 8 ohm speakers, which would be seen as 4 ohm loads in bridged mode.

Regards,
-- Al

Extreme high power amps are like owning a 450hp lawn mower. And if they're not, I still enjoyed making up the analogy.

Actually, he never asked about that. Regardless, it wouldn't make sense for Bryston to offer the bridge option if the amp couldn't at least handle a 4 ohm load. Most speakers drop down into 4 ohm territory. The company prides themselves on the fact that their amps can power just about any speaker.

And I agree with ZD that the preponderance of credible anecdotal reports is that the majority of amplifiers will not sound as good in bridged mode as in stereo mode. Probably even when driving 8 ohm speakers, which would be seen as 4 ohm loads in bridged mode.

ZD, I understand he didn't ask about that. I just wanted to let him know that he might want to look into that aspect of bridged amps.

Almarg, there's exceptions to the rule. Accuphase amps come to mind. Thanks for answering my question on which Ohms a bridged amp sees.

As far as power is concerned, I believe he's looking for sound equivalent to the 28BSST2, and hoped the 4BSST2 bridged will provide similar performance. As far as too much power is concerned, imo it's better to have it rather than need it and not have it.