Almarg,
excellent comments & observations esp. #1 as I was also thinking along the same lines. I've bashed B&W enough here (despite being a former B&W owner OR maybe because I was once a B&W owner) that I decided to stay away. ;-)
Then I noticed that you were thinking along the same lines & just had to pipe in..... :-)
One more thing - just because the Bryston amps are high wattage does not mean that they can source large amounts of current. I did not find any specs for the 4B-ST (tho' I did find a 1992 Stereophile review of the 4B). If the 4B-ST is anything like the former 4B then I read that the DC rails of the power amp are 85V! Meaning that the power transformer must be 60VAC. I have no idea what the VA rating of the power transformers are for the 4B-ST but that would have give some idea of the power delivery capacity. At any rate, the output transistors must be fantastically high voltage rated to run at 85V. IOW, at 85V the current handling capacity of some BJT power transistors is severely degraded i.e. they cannot handle much current while remaing inside their safe operating area (SOA). Thus, you have the high wattage of the 4B-ST but might not have the current delivery capability that B&W speakers so -l-o-v-e-. Hence a bass that is lacking heft.
Looking at the 4B-ST chassis leads me to believe that this thought process is on the correct track.
If the 4B-ST was a current delivery power-house the chassis would have looked like a Pass Labs 350 power amplifier Or a Plinius SA-250, for example.
excellent comments & observations esp. #1 as I was also thinking along the same lines. I've bashed B&W enough here (despite being a former B&W owner OR maybe because I was once a B&W owner) that I decided to stay away. ;-)
Then I noticed that you were thinking along the same lines & just had to pipe in..... :-)
One more thing - just because the Bryston amps are high wattage does not mean that they can source large amounts of current. I did not find any specs for the 4B-ST (tho' I did find a 1992 Stereophile review of the 4B). If the 4B-ST is anything like the former 4B then I read that the DC rails of the power amp are 85V! Meaning that the power transformer must be 60VAC. I have no idea what the VA rating of the power transformers are for the 4B-ST but that would have give some idea of the power delivery capacity. At any rate, the output transistors must be fantastically high voltage rated to run at 85V. IOW, at 85V the current handling capacity of some BJT power transistors is severely degraded i.e. they cannot handle much current while remaing inside their safe operating area (SOA). Thus, you have the high wattage of the 4B-ST but might not have the current delivery capability that B&W speakers so -l-o-v-e-. Hence a bass that is lacking heft.
Looking at the 4B-ST chassis leads me to believe that this thought process is on the correct track.
If the 4B-ST was a current delivery power-house the chassis would have looked like a Pass Labs 350 power amplifier Or a Plinius SA-250, for example.