[dubkarma]

Not being in a position, for now, to afford a 4B3, I am considering buying a 2011 4B-SST2 from a local fellow.

When comparing the back panel of the 4B-SST2 to the 4B-SST I've enjoyed for some years, I noticed one striking difference.

The power consumption (if that's the correct term) of the 4B-SST is specified as 2100 VA while that of the 4B-SST2, 550 Watts.

Can any one translate one of those into the other for me? Or explain what they mean?

For now I'm wondering how a class A/B power amp rated at 2 x 500 W into 4 ohms could only draw 550 Watts.

But maybe I just don't understand what I'm reading. . .

Any help appreciated!

[jcn3]

Not being in a position, for now, to afford a 4B3, I am considering buying a 2011 4B-SST2 from a local fellow.

When comparing the back panel of the 4B-SST2 to the 4B-SST I've enjoyed for some years, I noticed one striking difference.

The power consumption (if that's the correct term) of the 4B-SST is specified as 2100 VA while that of the 4B-SST2, 550 Watts.

Can any one translate one of those into the other for me? Or explain what they mean?

For now I'm wondering how a class A/B power amp rated at 2 x 500 W into 4 ohms could only draw 550 Watts.

But maybe I just don't understand what I'm reading. . .

Any help appreciated!

according to the manuals, the sst and sst2 have the same power consumption:

[dubkarma]

Good to know! Thank you.

I'd still, though, like to understand what data Bryston is putting on the back of their amps.

Having looked around the Net a bit more, I see they sometimes print figures denoting W(atts), sometime A(mps), and sometimes VA (transformer rating?).

Like power output, which is always denoted in Watts, you'd think there'd be a reason to be consistent.

Fortunately, this inconsistency does not detract from their performance!

[jcn3]

Good to know! Thank you.

I'd still, though, like to understand what data Bryston is putting on the back of their amps.

Having looked around the Net a bit more, I see they sometimes print figures denoting W(atts), sometime A(mps), and sometimes VA (transformer rating?).

Like power output, which is always denoted in Watts, you'd think there'd be a reason to be consistent.

Fortunately, this inconsistency does not detract from their performance!

FYI -- Power (W) = Volts (V) x Amps (A).  Not sure why sometimes you see W and sometimes VA.

[dubkarma]

FYI -- Power (W) = Volts (V) x Amps (A).  Not sure why sometimes you see W and sometimes VA.

I am aware of this formula, but I don't think it applies in the context I'm discussing.

W = V x A is, if I'm not mistaken, a formula to calculate an amp's power output.

The figures Bryston prints on the back of its amps have to do with the amp's power requirements and/or power consumption—the required electrical input, if you will, rather than the power output.

Examples of two 4Bs I have:

4B-SST:  120VAC/60Hz/2100VA
4B-SST2: 120VAC/60Hz/550W

These figures, I presume, have nothing to do with the amps' power output which in both cases is rated at 300/500 Wpc @ 8/4 ohms

The "2100VA" figure may describe—just guessing here, hence my enquiry—the combined rating of the two power transformers.
But the "550W" figure given for the 4B-SST2—I can only imagine of what that may be the measurement.

Again, this has nothing to do with functionality or compatibility with other components or anything like that—I just like to understand all manufacturer's specifications—in this case, why Bryston would use what seem to be completely different measurements on different, but very similar amplifiers.

[Speedskater]

Watts is into a Resistive load
Volts/Amps is into a reactive load. that's a load that has a fair amount of Capacitance or Inductance.
It may or may not also have a Resistive load.