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Old Crow's Synth Shop: Korg Mono/Poly Upgrade & Repair Overview

Welcome to the Mono/Poly synth shop at the Old Crow's Network. Here you will find detailed, fully illustrated information on how to make repairs and upgrades to the now-vintage and classic Korg Mono/Poly 4-oscillator music synthesizer. This machine was designed and built by the Keio Laboratories of Tokyo, Japan in 1980-81, and was available for retail sale from 1981 to 1984. Over 10,000 of them were sold, and today are highly sought after (as with most real analog gear from the 1970s and 1980s) for their razor-sharp bass capabilities. Of course the Mono/Poly is great for all sorts of timbres, not just bass, but that seems to be the main interest in it these days.

The Mono/Poly has all sorts of modulation routings, but curiously absent is a sample and hold (S/H) function that provides the familiar random voltages for filter and pitch modulation. Adding S/H to a Mono/Poly is pretty easy, however, and a fully-illustrated procedure will be provided here in the near future. For now, however, I will show the schematic of the S/H add-on, along with a few notes as to installing it. Pictures will soon follow.

Contents

S/H Mod--the Short Version


Scott Rider -- oldcrow@oldcrows.net