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From: chan@ames.arc.nasa.gov (Jeff Chan)
Newsgroups: rec.audio,sci.electronics
Subject: Re: Choosing Op-Amps
Message-ID: <1520@eos.UUCP>
Date: 14 Sep 88 19:13:47 GMT
References: <1152@ucsd.EDU>
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From article <1152@ucsd.EDU>, by brian@ucsd.EDU (Brian Kantor):
> As part of my design for a really wonderous hi-fi preamp, I've been
> trying to choose the right op-amps to use - or indeed, to discover
> whether simple discrete transistor or FET amplifiers might be better.
> 
> For the RIAA phono preamp section, a simple LM540 with about 20dB of gain
> winds up with a frequency response well past 20kHz, and a slew rate of
> better than 3V/uS, which is pretty respectable (I think).
>... 
> Finally, I think a LM540 will do nicely for providing the required 10dB
> or so of preamp gain to drive the power amp to full output from
> line-level input signals, and also the tape deck dubbing outputs.
> ...
> These are based on a 10-year-old IC op-amp design book.  Are there
> better chips for this purpose made these days?  Any recommendations?

Can't tell for sure, Brian, but it sounds like one of Walt Jung's books.
See his update titles "Audio IC op-amp applications, 3rd ed" on Sams
for revised reasoning and recommendations for op amps.  It is very current
(1987 copyright, I think).  On a consumer note, the book updates only
some of the basic theory parts and all of the audio parts of IC op-amp
cookbook, so both books may be useful to have.

The 540 is still good, but there may be fresher designs out that will
do what you want better.

Jeff C.
Internet: chan@ames.arc.nasa.gov
UUCP:     ames!chan