Octave "The Cat" -1977    Weight= Lbs. Number mfg.= ? MRP=$799

User Manual: Octave Cat page
Reset Proceedures: N/A
Operating System code: N/A
MIDI or other control protocol: N/A
Software related Links: N/A
Patches or knob settings: I've taken digital photos, but Octave cat page has a template.
Circuit Overview: below
Scematics/Service Manual: fdiskc archive or Octave Cat page SRM+ or Synthfool's SRM1
Common Service Issues/Tips: below
Parts Sources: Keys knobs semiconductors misc
Uncommon chips/modules used: SSM2040 VCF in plain "The Cat" and earlier SRM rev A, SSM2044 VCF in rev. B and that + CEM3340 VCO's in SRM-II. CA3046 transistor arrays used in VCO also as I recall on early ones.
Modifications:Octave cat page
General Info Links: Vintage Synth or Octave page (If anyone knows where John's old page went let me know)

Circuit Overview:
     Classic analog with cross modulation and flexible routings. And...a non-linear taper pot that goes 1 full step the first half of the movement up or down and the rest of the octave in the next half! Reeeow! Very discrete circuitry for '77 Due probably to legalities with ARP some of the duophonic circuitry got re-baked I think in the later versions.

Service Tips:
     Tuning tips for non-SRM model might be helpful as well. I've seen several problems with the SRM. A bad resistor heating a transistor array in mine I recall, taking out vco1. I recall some problem with envelopes...ahh yeah I replaced a bunch of 4016's. Just get a bag of them and go to work if it's like mine was! (After doing some diagnostics to confirm that it might be those that is. They're cheap and fail prone it seems in these. )

Check digi-key for slider caps!Black - 401-1215-ND, White - 401-1216-ND, Grey - 401-1217-ND,Red - 401-1218-ND

I think I have nearly all if not all parts for these machines. There are some resistor networks that one might have to wire in discretely. The SSM2040 is available rarely on ebay etc. but here is a engineered SSM2040 replacement Module
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