ACS MIDI CV/Gate :  PCB

The PCB

Polyphonic (new version 2.1) /LITE Versions

 

 

 

 

 

 The PCB can easily be made with toner transfert paper (PnP Blue). The documents can be printed directly. The text must be read normally on the copper side of the PCB.

Don't forget the 3 straps and make sure that the CI are in the right way. The CA3140 are in the opposite direction of the others.

 

The document is formatted to be printed directly on a mylar for photo-etching or a "press & peel" paper. Make sure that when the printed face of mylar is in contact with the copper side of the PCB, the lettering can be read normally

Trimming

To cancel the offset voltage of the AOP, connect a multimeter on the CV output and set the trimmer B to obtain an output value as close as possible of 0 mV.  Less that 0.2 mV is enough.

To tune the CV ouput, first connect it to a powered up VCO. Set the B trimmer to get exactly 1 Volt per octave.


 

Components Layout 

 

 

 

 

 

 

 

 

 

 

Please note that a 0.1µF capacitor must be soldered on the copper side of the PCB, under the PIC. It will be easier if you use a SMC.

 With the version 2.2 of the firmware you can use only one switch (ON-OFF-ON) for Mono-Poly4-Poly1 and a small push button for Reset. Connect the ground at the center of the switch and the wires (mono/poly) and (1ch/4ch) at each side.

LITE Version : 

To power this module with a +5 V voltage a 10 ohms resistor or a self (VK200) must be placed beetween (3) and (1) or above.

To power this module with a 7 to 25 V power supply, place a 78L05 voltage regulator as indicated on the schematics.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Front Panel

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Part list 

 

Component  : Quantity



6N137 : 1
PIC 16F88 or 16F87 (DIP 18 pin package) : 1
MCP 4822 Microchip : 2
CA3140 : 4
1N4148 : 6
BC547C : 4
Yellow LED : 4
Green LED: 1

Resistors

10 : 3
220 : 5
470 : 6
1k : 5
4,7k : 8
10k : 2
33k : 4
130k : 4
200k :4
25 turn 10 K vertical trimmer : 8

Capacitors

0,1 µF : 12
10µF : 2
22µF : 2

Other

Choke self  VK 200 : 1
3 positions Inverter on-off-on  : 1
Socket, jack, 1/4'' : 9
Socket DIN : 1


 LITE Version

6N137 : 1
PIC 16F88 or 16F87 (DIP 18 pin package) : 1
MCP 4822 Microchip : 1
1N4148 : 1
Yellow LED : 1 
78L05 : 1 (if power supply > 5 V) 

Resistors :

10 ohms : 1 or self VK200 (if  +5V)
47 ohms : 2
220 ohms : 1
470 ohms : 3
1K : 1
10K : 1 

Capacitors :

0,1 µF LCC : 4
22 µF : 1