2600 repair suggestions needed

Christopher_List at Sonymusic.Com Christopher_List at Sonymusic.Com
Fri Jan 17 15:36:26 CET 1997

> The optimum opamp replacement is gonna really depend
> upon the circuit context.  The LF411 is often the choice for low-offset
> a low-noise audio opamp for low-noise audio applications, a high speed
> opamp for square waves, and so forth.  Choosing the right opamp at
> each point is an all important part of Electrical Instrument Nerd
> Bonding Process.


Just a reminder that one of the cornerstones of the Nerd Bonding Temple is
"The Art of Electronics" by Horowitz and Hill. Chapter 4 deals with op-amps
and has some great tables that list lots of op-amps along with their specs
all side by side so you don't need to go flipping through a pile of data
sheets to figure out which one you want to use. Chapter 7 is dedicated to
precision op-amp techniques (low noise, high accuracy, etc.). "The A of E"
is very fond of the LF411 as a general purpose op-amp, and it <does> have a
excellent mix of specs for speed, offset, input impedence, and noise at a
reasonable price.

My gereral rule of thumb is to use LF412's or AD712's (they're actually
$2.40 each, not $4) in places where high speed and/or accuracy is important
- like VCO exponential converter and output comparator circuitry. Use
TL072's in low noise situations, - I qualify audio signal path as low noise
- like external input amps, filters, VCAs, wave shapers, etc. Use
whatever's handy and decent for simple, non-critcal stuff - like cv summers
in the VCA, filter, and wave shaper, etc....

- CList

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