[sdiy] Korg SDD-1200 schematics

[Florian Anwander]

Hello everybody,

thanks again for all the tips with the moog prodigy schemoes: After
replacing a 4007 in the envelope section the moog sings again...


Now the next question: is there someone with the schematics of the Korg
SDD-1200 Delay. About a year ago a friendly person with the name "Lutz"
faxed them, but unfortunately the low resolution of the fax and the
bleaching of the thermo paper made it partially unreadable. And I do not
have any contact to this person.  Now I'd like to add a CV-Input for the
clock generator. Is there occasionally anyone who owns the Service manual
and who could scan it for me?  



BTW: a simple but very nice modification is to replace the inverted
feedback by a ping-pong feedback: Unfix the potentiometer board (this are a
lot of screws) and turn that way, that the component side lies on the
mainboard. At the double pot of the Feedback, break up the connections
between the left two solderpoints to the 8-pin-connector


                Front  

             o   o   o   o <---- potentiometers solder points
            /   /   /   /  
           |   |   |   |            
           | o | o | o | o
           | | | | | | | |  
 breaks>>> = | | | | | | |           
       >>> | = | | | | | |
           | | | | | | | |



Now simply solder crossed wires from the first solderpoint to the third
solderpoint of the other half of the dual pot. 


             o  o  o  o
             \     |
              \___ ,  
              ___,\
             /     |
             o  o  o  o
            
  
Now fix the potentiometer board back and fix lid. Done. 
Now, turning the feedback to the right works as usual, but turning it to
the left feeds the output of channel A in the input of channel B and vice
versa. Turning both channels to the left causes a pingpong feedback.



And another hint: The feedback is trimmed very puritanical, means no
excessive dub delays are possible. But this can be changed: close to the
other end of each of the cables which are connected to the mentioned
8-pin-connector is a trimmer, that restricts the amount of feedback...



Florian