Vladimir said:
davedotco said:
I was assuming all things being equal, ie the same size power supply 'in proportion' to the power output. As you say, the real difference is in the detail, power supply capacity and response time is a big issue, I'm not quite so sold on regulated supplies, but in general power supplies are pivotal.
Eh... Regulated power supply works brilliantly within its design remit. Once the load demands more, there is no sagging voltage rails and blunt sound, the amplifier cuts off completely.
Fully regulated power supplies are the only trait worthy of praise in Naim and Exposure amps of old IMO. That is how they got away with 30W amps pushing power hungry isobariks. No regulation = no foot tapping.
Not entirely true Vlad.
Fully regulated power amplifiers can sound very good but at a substantial cost which is not always worthwhile. The big disadvantage is, as you yourself pointed out, the inability to go beyond its rated peak capability.
This can be a big issue in some cases, we know how much power can be required from an amplifier, and if they exceed the maximum power the signal will be clipped. Regulated amplifiers may be great at supplying current into difficult loads but given the reduced voltage rails, they will clip early.
On the other hand an amplifier with the same sized but unregulated power supply can often produce peaks that go well beyond it's rated capability, particularly in designs that use plenty of psu capacitance in their design.
Since you brought them up, it was well understood that a Nap250 would drive 'Bariks to higher levels than the Nap135 though the latter sounded better at lower levels as they handled the very low impedences better.
This as a good comparison as, in early models at least, the 135 had the same power supply and power amp board as the 250, with the power regulation board taking the place of the second amp board. If I recall correctly the 135 had a very slightly lower rail voltage than the 250, and a slightly lower rated output, an indication of just how much power supply is needed to produce a fully regulated amplifier.
So whilst I agree that power supplies are pivotal, I am not entirely sure that full regulation is the best answer. What would have been interesting would have been a 135 style mono amplifier but without regulation, just a more potent amplifier board.
Never happened sadly, but a 150watt unregulated mono amplifier would have been interesting.