From: John Woodgate
Subject: Re: Output Impedence
Date: Wed, 30 Oct 2002 20:45:14 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Wed, 30 Oct 2002 21:19:47 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that Tom Bruhns wrote
(in <firstname.lastname@example.org>) about 'Output
Impedence', on Wed, 30 Oct 2002:
> But the summary is:
>peaking at high freq with a 10k load. High freq falloff with a 600
>ohm load. Both limit the freq response (+/-0.1dB) to about 12kHz.
>But an optimized load extends the response to 109kHz. There are
>similar benefits if you measure to +/-3dB bandwidth.
OK, but you are in esoteric audiophile country with your numbers. +/-
0.1 dB is MUCH tighter than the specs on any likely source of your
programme material. OTOH, 3 dB is a bit 'coarse' these days. +/- 1 dB is
realistic. And a requirement for a bandwidth of over 100 kHz is perhaps
realistic for a professional recording mixer, where multiple passes of
the audio through the circuits may occur, and high-frequency phase-shift
accumulation may be a problem, but for other applications, it just
represents an EMC immunity problem.
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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