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Re: Required Reading on DA

I would suggest a quick read of the article below. It CLEARLY shows the effects, at AUDIO bandwidths, of capacitor DA on line level electronics. Perhaps we can actually learn something, rather than simply arguing.......

Been there, done that.

Would you like to see what Bob Pease himself had to say about DA in cable dielectrics at audio frequencies?

Yes, the model is IN CONCEPT valid for AC sines as well as for steps, but NOT important. See below.

Steve, lets' say a 100 ft stretch of speaker cable has 1000 pf. The soakage of a mylar cap of that size would be about 10 pF in series with 1 meg.

You drive this from an amplifer whose output impedance is lower than 1 ohm. In concept if you put this in a precision measuremnt system, you could measure perhaps as low as 0.01 dB of attenuation.

(YOU MUST AGREE - you certainly can't HEAR that kind of attenuation shift, 0.01 dB...)

But the soakage of 1 megohm, is below the 0.01dB by about a factor of 1000. If you want to wast your time by arguing with audio nuts about things that are 1000: 1 below the limits of MEASURABILITY - not to mention 100,000:1 belowthe limits of audibility --

-- BE MY GUEST, but don't waste MY time, OK?

Yeah, if you ran speaker cables not just 100 ft, but 10,000 ft. - and if you ran a rubber line cord that is perhaps 10 x worse than mylar - you might be able to measure it.

WHO CARES!

If you ran wire 900,000 feet, the soakage might IN CONCEPT become important, except the signal coming out the end would be distorted by some MUCH bigger effects, and the audio output would be INAUDIBLE.

Forget it.

Best regards. /rap

That's from an EMail I received from him a couple years ago.

se





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