What is more important to get big SS amps to really sing: current draw from electrical line or capacitor size?
If one's amp contains a bunch of capacitors the size of small beer kegs, are 20 amp cords on even the biggest power amps just marketing gimmicks to impress audiophiles?
Taking those two items alone, it's capacitor size - and to draw from a popular line , it's not the size but what you do with it that counts! I had a Perreaux with those beer kegs, and that was the weakest part of the amplifier!
Vastly superior are arrays of small caps, located precisely where they are most effective - doesn't have the Wow! factor, but far better at getting the job done. Power supplies in these monster amps are sometimes badly engineered - thus here a marketing gimmick; it is as hard to get a power supply right as it is the amplifying circuit - if not done well that will kill the amplifier's potential performance, stone dead.
As Frank says, its not about how much you've got, rather how low an impedance supply your caps are making. For one example of an excellent looking power supply look at Nagra's amp - they have large caps but also check out how they're wired : http://www.nagraaudio.com/wp-content/gallery/hd-amp/HD_AMP_inside.jpg
it is as hard to get a power supply right as it is the amplifying circuit - if not done well that will kill the amplifier's potential performance, stone dead.
Absolutely. The reason why many tube amps have a tubey sound instead of a linear one is that their power supplies just cannot deliver the 300-400 V DC well under any circumstance -- too often the supply sags under load. The "tube sound" is not the tubes' fault, but the fault of them not constantly working under optimal operating conditions because of an inferior power supply. You want to have tight bass and extended highs from a tube amp? Get the power supply right.
The stock power supplies already had been beefed up before, but external BorderPatrol power supplies brought the sound yet to another level. Here is my review:
On my system thread (see my signature) you can also see the power supplies, including a picture with one of them opened.
Yet my amps do not seem to have been the most egregious example by long shot. Here is from a review of external BorderPatrol power supplies by Roy Gegory:
If I was impressed by the performance on the Innovations amp, it did nothing to prepare me for the transformation wrought on the Audio Note Meishu, a £3500 single-ended integrated running one 300B per channel. In stock form this amp could only be described as disappointing. The musical picture it paints is grey, flat and disjointed, with no separation to talk of and no dynamic discrimination. The overall effect is congested and messy, exacerbated by a splashy tendency and very poor control: All in all a bit of a sonic disaster area.
Adding the BP Standard PSU brought about a Cinderella makeover of the kind that day-time TV producers can only dream about. It was as if the milling herd of musical notes had been rounded up and sent off in a single direction. Now the music had a sense of unified energy and purpose. Individual instruments and voices were properly separate and took on something approaching their real colour. All of a sudden the rhythm and pace of the music hove into view like a ship out of the fog and we were off and running. Diane Christiansen’s acerbic delivery regained its sardonic twist, the musicians started to actually play together. In fact, it’s difficult to overstate the magnitude of this improvement. Any Meishu owners out there would be shocked to the core: the designer should seek a very, very dark room.