Amp output is wired in series vs parallel?

Just read the Sterophile review of the 1000 watt monoblocks from Bryston, the 28B SST. it mentioned that each monoblock is two amps bridged, wired in series. But they also mention that if you want to play low impedance speakers of 4 or 2 ohms, you should have Bryston wire the amps in paralell at the factory.

My question is, does the amp being wired in series or paralell affect the power rating of the amp? What is the effect sonically on the amp if it wired parallell vs series?

The link to the review is below:
Yes it does.
I would say that in general wired in series (1000 watts) but wired in parallel give fewer watts at 8 ohms and more amperage into low impedances.
Most bridged amps do not do so well into low impedance loads. that is why Bryston offers the alternate method of 'bridging' to better handle the low impedance.
Think of a pair of pumps.
'Series' is one pump followed by another pump. each adding pressure (watts) with 'less' area
'parallel' is like two pumps side by side, both pumping into the same tank. Less pressure (watts) but more volume in square inches 'area' (amps)
Low impedances need more area. high impedances need more pressure.
If this analogy does not help you please just ignore it.
Series: Same current, up to 4X voltage (often factory derated to handle stress from low impedance loads, ie. lower voltage rails- Aragon Palladiums). True bridged/differential.

Parallel: 2X current, same voltage. To keep sides from conflict, a 1 to 2 ohm resistor is used in parallel. "Monostrapped".

Shouldn't it be 2x voltage in bridged?
Kijanki, 2X looks right to me -- the voltage should sum.
Hi Mitch,

In the paralleled configuration, power capability into 8 ohms will be MUCH less than in the bridged configuration. It will probably increase significantly into 2 ohms, and not change dramatically into 4 ohms. And based on JA's comments about distortion, sonics with a 2 to 4 ohm load will most likely be better in the paralleled configuration.

Elizabeth's comment is spot on, with the slight correction that the reference to "pressure (watts)" should say "pressure (volts)."

NGJockey's comment is correct, except for what I suspect is his inadvertent mention of 4x voltage, which should be 2x voltage as Kijanki and Bob pointed out. Bridging potentially increases voltage swing capability by 2x, and power by 4x, but current limitations, thermal considerations, and other factors usually limit those increases to significantly smaller factors into 8 ohms, and to much smaller factors for low impedance loads.

Also, I suspect that the 1 to 2 ohm resistor he mentioned is probably just applicable to some paralleled designs but not to many others. Where a resistor of that large a value is used there would be a major impact on damping factor and output impedance, and therefore on frequency response flatness if speaker impedance varies significantly with frequency. I would suggest that anyone considering purchase of a monostrapped (paralleled) amp ascertain its damping factor before finalizing their decision, and consider its appropriateness for the particular speaker that is being used.

Best regards,
-- Al
Ya, definitely oversimplified that at 8:00 AM. Can't deal with current limiting till after the second cup. Thanks Al, for being more precise.

Bryston does use a 1.5 ohm resistor on the parallel 7B's. Not sure about the 28B's. Seen jumper wires for paralleling some Macs that didn't use any resistor. Don't ask me if those were autoformer models. Only other monostrapping I've heard of has been on tube amps, which 95% suggests output transformers. Can't think of any other SS amp manufacturer that has recommended that method.

Mitch, if you're thinking for the Kappa's and maybe even the Beta's, parallel might be the only viable choice of either. However, I did use dual bridged Plinius SA100's on Kappa 8's very briefly and continue to use them with Genesis 350's ( on 4 ohm mid/tweeter, resistive load, dedicated bass amp/active xover). For that one hour on the 8's, it was the best bass I ever got out of them but still sloppy by comparison to the 350's.
Ngjockey, you are spot on, this whole thread was started with the Kappa 9 in mind. I think bi-amping with two pair of 7B SST might be a better option. Too many questions about the 28B SST low ohm performance. And at $16k per pair for the 28B, I'd need better peace of mind at those prices.
On the SST, parallel operation is a factory option, not a switch like the earlier versions. Should be an easy mod.
Mitch4t, why not try and then post your findings, if you don't you will never know.

Do you know of anyone else using the same speaker you have, if so what have they tried.