Oberheim 1675C Voice Card Configuration

4k Tom EPROM in a Mark II (1675C) voice card

Generic single 2732 Mark II  

All jumper blocks are numbered starting with pin 1. Horizontal jumper block pins are numbered from left to right, vertical blocks are numbered from top to bottom.

Component Setting Value Comments
U8 Installed 2732 4k Tom sample
U9 Not installed - -
Jumper A Connect 1 to 4 wire Set VCA envelope response
Jumper B Connect 1 to 3 or not installed wire Don't care
Jumper C Connect 2 to 4 wire Enable EPROM U8 on all triggers
Jumper D Connect 2 to 3 or not installed wire Don't care
Jumper E Connect 2 to 3 wire Sound length = 4K
Jumper F Connect 3 to 4 wire Sound length = 4K
Jumper G Connect 2 to 3 wire External CV controls pitch
Capacitor C1 Installed 0.0033uF Sets nominal sample rate
Capacitor C3 Not installed - Sets VCF envelope decay time
Capacitor C4 Installed 6.8uF Sets VCA envelope decay time
Diode D1 Installed 1N4148 Trigger 1 reduces pitch
Diode D2 Not installed - Trigger 1 reduces volume
Diode D3 Installed 1N4148 Trigger 2 reduces pitch
Diode D4 Not installed - Trigger 2 reduces volume
Diode D5 Installed 1N4148 (not used)
Resistor R4 Installed 10K Trigger 1 pitch change depth
Resistor R5 Installed 33K Trigger 2 pitch change depth
Resistor R7 Installed 4.7K (Not used)
Resistor R8 Not installed - Sets VCA control
Resistor R9 Not installed - Trigger 3 has no effect on VCA envelope
Resistor R11 Installed 2.7K Sets VCA envelope modulation amount
Resistor R12 Installed 4.7K VCF tracking control
Resistor R13 Not installed - VCF control
  1. All diodes 1N4148
  2. All resistors 1/4 watt, 5%

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