Discussion about the Korg PolySix synthesizer

Hi,

I have previously modified my Polysix to accept an external signal
into the FX generator.  After two years of perfect operation, the
machine is now totally un-usable, and I would love to move the
KLM-368A effect board into a separate chassis and use it as a
dedicated unit.  The only problem I have is, what circuits are
required to connect the effect select switch and level control to the
board?  I assume that the effects board needs some kind of signal from
the programmer section, but I want to just connect the pots themselves
to the 386A with a minimum of extra circuits.  Is there a way to do
this using the pins on CN-03?  Please help, it would be greatly
appreciated.  As a side note, all of the other parts from my Polysix
are available for sale or trade, I have been advised that the
Programmer IC is possibly damaged, but all of the other boards, pwr
supply and case are available.  Please let me know if anyone is
interested in these parts, and thanx for the tech advice.  
Would also love to get my hands on a similiar Korg analog machine.
Regards,

T. Cardinal

exactly how did you modify it to accept an external
signal? i've open mine up and tried to figure it out,
but to no avail...
i'm not too knowledgable about circuits, but i'm very
handy with a soldiering iron...

thanks
- roy


--- trekpilot <trekpilot@yahoo.com> wrote:
> Hi,
> 
> I have previously modified my Polysix to accept an
> external signal
> into the FX generator.  After two years of perfect
> operation, the
> machine is now totally un-usable, and I would love
> to move the
> KLM-368A effect board into a separate chassis and
> use it as a
> dedicated unit.  The only problem I have is, what
> circuits are
> required to connect the effect select switch and
> level control to the
> board?  I assume that the effects board needs some
> kind of signal from
> the programmer section, but I want to just connect
> the pots themselves
> to the 386A with a minimum of extra circuits.  Is
> there a way to do
> this using the pins on CN-03?  Please help, it would
> be greatly
> appreciated.  As a side note, all of the other parts
> from my Polysix
> are available for sale or trade, I have been advised
> that the
> Programmer IC is possibly damaged, but all of the
> other boards, pwr
> supply and case are available.  Please let me know
> if anyone is
> interested in these parts, and thanx for the tech
> advice.  
> Would also love to get my hands on a similiar Korg
> analog machine.
> Regards,
> 
> T. Cardinal
> 
> 
> 


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Attaching standalone controls is not too difficult, although the 
following details should be observed:

  The KLM-368 has three logic lines to select effect mode.  If all lines
are low (0V), then the effects are turned off.  Each individual line
enables a particular effect mode: chorus, phase or ensemble when taken
high (+5V).  I am unsure what response happens of more than one mode is
enabled at once.  Chrous mode is CN03-2, phase mode is CN03-3 and ensemble
mode is CN03-4.

  In addition, there are four control voltages.  Effect Speed is achieved 
by using a 50K linear potentiometer with CCW lug at -5V, CW lug at +5V and 
the wiper lug to CN03-1 on the KLM-368.

  There are *3* volume level inputs.  One is to reduce the gain as the 
filter resonance increases, one is the attenuator level as set by the VCA 
attenuator switch and controlled by a 4-bit DAC.  The last input is the 
VCA modulation CV for things like tremolo.  Of these, I would just use the 
VCA mod input and wire the others (CN03-6, CN03-7) to +5V through 1K 
resistors.

  The VCA mod input (CN03-5) can be a potentiometer wired like the Effect
Speed line above.

  The first thing I would do, however, is just try to get the Polysix 
running again.  If you need a new KLM-367 MCU, I have one I can send you 
for cheap.

Crow
/**/

On Fri, 17 Oct 2003, trekpilot wrote:

> problem I have is, what circuits are required to connect the effect
> select switch and level control to the board?  I assume that the effects
> board needs some kind of signal from the programmer section, but I want
> to just connect the pots themselves to the 386A with a minimum of extra
> circuits.  Is there a way to do this using the pins on CN-03?  Please
> help, it would be greatly appreciated.  As a side note, all of the other
> parts from my Polysix are available for sale or trade, I have been
> advised that the Programmer IC is possibly damaged, but all of the other
> boards, pwr supply and case are available.  Please let me know if anyone
> is interested in these parts, and thanx for the tech advice.  Would also
> love to get my hands on a similiar Korg analog machine. Regards,
> 
> T. Cardinal

--- In PolySix@yahoogroups.com, "roy s." <unovis_yeah@y...> wrote:
> exactly how did you modify it to accept an external
> signal? i've open mine up and tried to figure it out,
> but to no avail...
> i'm not too knowledgable about circuits, but i'm very
> handy with a soldiering iron...
> 
> thanks
> - roy
> 

Hi Roy.

Modifying the effects board for an external IN is very simple.  All I
used is a SPDT toggle switch, a mono jack, and a tap to the effects
signal in line.  I simply wired the external jack tip (signal) line
into one side of the switch.  The other side of the switch is the
synth signal line (for normal operation.)  The center pole leads to
the Signal IN line of the effects board (yel/wht cn-14).  This allows
you to switch between the synth voices and your external signal. 
Don't forget to ground the jack ring connection...I simply connected
it to the other jack grounds.

There are two additional steps: 1) solder a 100ohm resistor between
the external signal jack and the switch lead to decrease the signal
level.  Also, it is up to you where you want to mount the switch and
the jack.
On my setup, I send the signals from my AX80 into the Polysix effects
board.   Haven't tried it with recorded audio or other signals, but
this should work for you.  

                         O-------------- Synth signal 
To FX signal in--------O
(KLM-386A CN14 pin 1)    O-----/\/\/\--- External signal (jack tip)
                               100ohm 

Hope I've helped, and have fun with the toys!  Let me know if you have
any other questions I can help you with.

----- Original Message -----

From: "roy s." <unovis_yeah@yahoo.com>
> exactly how did you modify it to accept an external
> signal? i've open mine up and tried to figure it out,
> but to no avail...
> i'm not too knowledgable about circuits, but i'm very
> handy with a soldiering iron...

I don't have a schematic so I can't tell you anything specific about the
Polysix.  But in general terms, audio flows in one direction; from the output of
one device to the input of another device.  If you break such an audio path
with, for example, a pair of normalized jacks, you can take out or insert
signals that a manufacturer never intended.  With a little electronics knowledge
of IC and transistor circuits and an accurate schematic diagram, these things
can be sussed out.

Removing a circuit for stand-alone operation requires additional knowledge of
how the device works, what controls it, and a way to supply it with appropriate
power.

Cheers,

Bill (in vague terms mode)

thanks! i'll give it a try this week.
- roy

--- trekpilot <trekpilot@yahoo.com> wrote:
> Hi Roy.
> 
> Modifying the effects board for an external IN is
> very simple.  All I
> used is a SPDT toggle switch, a mono jack, and a tap
> to the effects
> signal in line.  I simply wired the external jack
> tip (signal) line
> into one side of the switch.  The other side of the
> switch is the
> synth signal line (for normal operation.)  The
> center pole leads to
> the Signal IN line of the effects board (yel/wht
> cn-14).  This allows
> you to switch between the synth voices and your
> external signal. 
> Don't forget to ground the jack ring connection...I
> simply connected
> it to the other jack grounds.
> 
> There are two additional steps: 1) solder a 100ohm
> resistor between
> the external signal jack and the switch lead to
> decrease the signal
> level.  Also, it is up to you where you want to
> mount the switch and
> the jack.
> On my setup, I send the signals from my AX80 into
> the Polysix effects
> board.   Haven't tried it with recorded audio or
> other signals, but
> this should work for you.  
> 
>                          O-------------- Synth
> signal 
> To FX signal in--------O
> (KLM-386A CN14 pin 1)    O-----/\/\/\--- External
> signal (jack tip)
>                                100ohm 
> 
> Hope I've helped, and have fun with the toys!  Let
> me know if you have
> any other questions I can help you with.     


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