High Current vs high power

I, of course, agree with all of Ralph's (Atmasphere's) well stated points. I would just add that the miniscule amount of time for which a "high current" amp can provide large amounts of current into a dead short (10 milliseconds, or 1/100th of a second in his example), is generally not stated when maximum current specifications are presented. Which makes the 50 ampere or 80 ampere or 100 ampere kinds of numbers that may be presented for some amplifiers even more meaningless, because chances are those numbers for different amplifiers are based on different amounts of time.

08-25-13: Arh
The signal going into a power amp is usually high voltage and low current. The amp reverses this to low voltage and high current.

Alan, based on your posts I've seen in the past I suspect that you are sufficiently knowledgeable that you must have composed this statement before having your morning coffee. The voltage-related parts of it, that is. :-)

Regards,
-- Al

George, I would respectfully, but very strongly, disagree with the notion that specs, and a good understanding of them, are useless.

Yes, specs will generally provide little if any insight into how a component will sound. And I certainly agree that "buying based on specs" is almost certain to result in expensive mistakes.

However, I doubt that any serious audiophile having even a tiny modicum of experience "buys based on specs." Although those who express disdain for specs commonly seem to make the IMO false assumption that those who consider specs to provide value do buy in that manner.

The very considerable value specs can provide, as I see it, is that when purchase decisions are being made they allow candidates to be RULED OUT, on the basis that they would be poor matches with either other components in the system (e.g. impedance incompatibilities, gain and sensitivity mismatches, etc.), or with the listener's requirements (e.g., dynamic range and maximum volume capability).

Without taking advantage of those kinds of benefits that can be provided by specs (and a good understanding of them), the randomness of the component selection process increases greatly. As does the likelihood of expensive mistakes.

Regards,
-- Al

Thanks, Bruce. Yes, looking at JA's measurements of the Revel Ultima Studio 2 and your Ref150, it strikes me as a reasonable possibility that they would be a suitable pairing, using the 4 ohm tap.

George, I see your point. But I doubt that there are very many serious audiophiles who would either choose or reject an amplifier based on THD numbers, which are among the most useless audio-related specs I can think of. But even those numbers can be useful. I would be very hesitant to buy an amplifier having exceptionally LOW ("good") THD numbers, because that would probably signify heavy-handed application of feedback in the design. The probable consequences being sloppy performance on fast transients, and increased amounts of distortion components that are particularly offensive.

As far as power is concerned, yes, which of two amplifiers will "sound" more powerful has to do with dynamics, distortion characteristics, power supply quality, and other factors that don't have much correlation with the number of watts they can produce. However, to produce a given desired maximum volume level at a given listening distance, with a speaker having a given efficiency and given dispersion characteristics, requires a certain minimum number of watts. If the amplifier is substantially underpowered relative to that number, it suggests caution or rejection. If the amplifier is way over-powered relative to that number, it suggests that its gain should be looked into, because it raises the possibility that gain may be high enough to necessitate using the volume control at settings that are undesirably low.

So even those numbers can have their usefulness in some circumstances.

Regards,
-- Al