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Old Crow's Synth Shop: Korg Polysix Upgrade & Repair
Welcome to the Polysix 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 Polysix programmable
6-voice polyphonic music synthesizer. This machine was designed and built
by the Keio Laboratories of Tokyo, Japan in 1980-81, and was available for
retail sale in 1981 and 1982 before being replaced by the Korg Poly-61.
This author's opinion is that the Poly-61, while having two oscillators
per voice, did not have nearly the same degree of programmaing flexibility
as the Polysix, and the Poly-61 was therefore an inferior "successor".
The Polysix was one of the last machines built prior to the third
revelation in modern synthesizer design: the digital synthesizer. (The
first was Bob Moog's use of voltage-controlled elements, the second was
the incorporation of microcomputers into the hardware to allow for
programming, editing, and storage of patches). At the same time the
initial digital synthesizers were making their debut in 1982-1983 arrived
an innocuous little interface that was to change everything from
that time forward: MIDI, the Musical Instrument Digital Interface.
No longer were synthesizers isolated from each other. Now they could
talk a common protocol between themselves, allowing each machine's
keyboard to control the others, take instructions and scores from
computer sequencer/patch assigning/composing tools and likewise send the
realtime performer's keyboard playing to be recorded and recalled...just
to touch the start of the immense list of options that MIDI has opened up
over the years.
One of the items that will be present here on the Old Crow's Synth Shop
is how to put MIDI into your Polysix. Two approaches
will be offered: Richard Wolf's very nice Z80-based processor replacement
board that 1) provides a comprehensive MIDI capability and 2) replaces the
original Polysix CPUs with a single, much more capable processor to make
future upgrades easier. This approach requires moderate circuit-board
modifications, but the end result is a very flexible MIDI scheme. Richard
has a site detailing his project at his Polysix-M site. The
other approach features the second-generation design of my own MPX-61A
MIDI-to-Keyboard-Matrix encoder. This method requires almost no
modification to the Polysix itself. The original precis on the MPX-61A is
available at my MPX-61 site.
NOTE: If you have a Korg Polysix and have never changed out the original
backup battery, GET IT DONE NOW!! If you are not sure whether the battery
has been replaced, open the unit and do a
quick visual check. That battery is nearly 20 years old and long past the
end of its expected life. Ni-cad batteries such as the one originally
used on the Polysix do not go quietly, either. All too often they begin
to leak on their negative terminal and the resulting corrosion in the area
of the circuit board where the battery is mounted can cause the machine to
fail. ALL Polysix units are now subsceptible to this problem, so have it
checked out as soon as possible.
The Complete Polysix Battery Repair
Give Your Polysix a Korg PS3100-style Triple Resonant Filter
Scott Rider -- firstname.lastname@example.org