[sdiy] calling for 606 /808 gurus

[Plutonique9]

I posted this to AH a few weeks back, there archives have been down 
for a while now, so I'll repost them here. Enjoy!
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Hey people, I've been poking around the 606 for a couple of daze, 
modifying n' pokin'.... :)
So, if your into altering your 606, heres another 3 solid sound 
modifications (I'll write up more as I complete them).
You should download the 606 schematics from music machines before 
diving into this.
 
Open Hat decay ::
 
Smooth mod, similar to the TR-808 Open hat decay control.
It has come up on AH before on how the tempo control of the 606 
influences the Open hat decay, this is true, regardless of whether 
the 606 is set to external clock or internal clock. This is a more 
finite control over the decay, very suave.
 
Ok, locate capacitor "C46". You have to add a 500k potentiometer (or 
trimpot) in parallel with this Capacitor. I'll attempt a dodgy 
drawing of this :)
   
(Potentiometer)
       |
      V     
     ____
   /          \
  |            |
   \_____ /
    |    |    |
   (1) (2)
 
Solder insulated wires from these 2 legs of your 500k pot to these 2 
points at "C46"
 
(Capacitor "C46")
         |
        V
    _____
   |         |
   |         |
   |         |
    \____/
     |     |
     |     |
    (1)  (2)
 
Make a bit o' sense, hope so.
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Cymbal Decay control::
 
This mod is groovin, gives the cymbal a pretty impressive range of 
control over the decay, cranking the decay right down makes it sound 
like another closed hat, which is wicked u see, cause the original 
606 cymbal is kinda boring, the decay time is also extended from the 
original when the pot is turned fully up.
 
This mod involves removing resistor "R163" from the 606 and replacing 
it with a 2 meg potentiometer or trimpot, no drawing for this one, it 
too straight forward, solder an insulated wire from the middle leg of 
your pot to one of the holes of "R163" and one of the outside legs of 
your pot to the other hole of "R163", simple simon.
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Cymbal bandpass filter control II::
 
There are two bandpass filters used to control the tone of the 
cymbals, one is shared by the hi hats (this mod has been documented 
by Geoff Waterston), and the other affects the cymbal only.
If you have good ears, you may be able to here a certain "ringing" 
sound in the cymbals, this mod control the tone (or pitch) of this 
ringing, kinda boring but useful none the less.
 
This mod involves removing resistor "R222" from the 606, and 
replacing it with a 5k potentiometer or trimpot. "R222" can be found 
close to IC15. Wiring up a potentiometer or trimpot to this point is 
the same deal as the Cymbal decay mod, simple dimple.
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-- Plutonique9, Plutonique9 at symbiocom.com

http://www.mp3.com/Plutonique9