[sdiy] Op Amp Replacment for CV and Audio

[Oakley Sound]

> I'm looking to replace the 1458 dual op amps in an Octave Cat I'm
working on. I'll be using LT1013s (as recommended by Paul Schreiber) for
the op amps in the CV path in an effort to improve stability especially
for the VCOs.

Just to warn you, although the LT1013 is an excellent chip, it probably
won't do anything for the appalling drift in the Octave CAT's VCOs. Most
of the drift is coming from elsewhere in the circuitry. I would have
liked to spend some time looking into this when I had one in the
workshop a while back. I think the VCO itself is probably OK, although
it does use a 4093 schmitt as the VCO comparator. My suspicions lie with
the +/-7V zener regulated lines, but as I say I didn't spend so much
time with it.

The OP275 is a good all round op-amp for both CV and audio, but it still
won't beat the LT1013 for its DC specs, or the 5532 for its sound. But
the trusty TL072 is good one to try first.

Regards,

Tony Allgood                         www.oakleysound.co.uk

Oakley Modular Synthesisers      Penrith, Cumbria, England