Power Supply for Digital Amp.

*It seems to me that some marketing mumbo jumbo is going on about power supples in digital amps*

How about over-hyping the supplies in amps in general? After all, the purpose of a power supply in ANY piece of electronics is to convert AC into DC. As long as you just have plain DC that is properly regulated under load and keeps noise off the DC rails, whats the point in all this extra stuff? After all, DC is DC whether it comes from a Battery or a Power Supply. Yes, I know that you cannot make a power supply act as a battery perfectly, but you can come extremly close. Thats why I can't understand all the hype about power cord tweaks, etc., unless they filter out some of the line noise if you have it.

If, say, you need a constant +/-90V Supply for the output transistors, and your power supply is designed to deliver that voltage all the way up to full load, with very low noise, aren't you Done? 90VDC is 90VDC.

Joeylawn36111...There is much truth to what you say, although some amps have been (and are) made with less-than-satisfactory power supplies, because it is an easy place to cut corners and reduce cost. When the "rail" voltages of a power amp "sag" (go down) as a result of heavy draw when music is loud, the output of the amp would be affected EXCEPT that the feedback loop will detect the signal error and more fully turn on the output transistors to compensate for the lower voltage applied to them. Because the power supply voltages are heavily filtered, voltage variation will be very slow (compared with audio signals) and can be tracked by a feedback loop having little or no effect at audio frequency if feedback is considered undesirable. Finally, if power supply "sag" were really a problem we would see amplifiers with regulated "rail" power supplies. Are there any?

As you say, the role of the power supply is to provide a steady voltage, and nothing could be easier to verify.

The claim that I find most difficult to swollow is the superiority of tube rectifiers. Can someone elaborate on this?
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Good points there. I didn't know that.

I used to own a Ming-Da preamp with a tube rectifier that claimed that it was better than a solid-state one - at the time I read that, I was also skeptical. Just asking, but maybe the rectification waveform is not as abrupt (smoother and easier to filter) than a solid-state diode? Don't really know either - BUT I do know that you cannot simply replace the tube diode with a solid state one, as the transformer may burn up from too much current. I did this years ago when modding an old oscilloscope.

Eldartford, BTW - thanks for that reccomedation on a earlier post on the Behringer DEQ 2496. GREAT Equalizer.