Midimuso CV-12 User manual
Midimuso CV-12 ORAC
Thanks for buying the Midimuso CV-12 ORAC PCB.
This book et wi he p you construct / set up the kit.
For more information on modes, chaining, re-triggering, aftertouch, overf ow and
po yphony, p ease refer to the main CV 12 manua on the website (midimuso.co.uk).
Component placement (N.B. Not a the PCB ho es are used)
JP1 shou d be jumpered from centre to pin 3 (adjacent, right) so the IC receives MIDI from
the 5 pin DIN connector. C3 (1uF) may be po arised.
Its + termina shou d be nearest the top edge of the board.
They are marked as:
105 = 1 000 000pF = 1uF
104 = 100 000pF = 0.1uF = 100nF
103 = 10 000pF = 10nF = 0.01uF
The board can produce 1V / octave or 1.2V / octave or 0.5V / octave just by setting the
trimmer correct y.
(You'll need to increase the power supply voltage to 1 V for the 1.2V / octave scheme)
On power-up, adjust the trimmer unti you see:
Port Pin 1V / Octave 1.2V / Octave 0. V / Octave
================================================================
B 6 6.0 Vo ts 7.2 Vo ts 3.0 Vo ts
B 5 5.0 Vo ts 6.0 Vo ts 2.5 Vo ts
B 4 4.0 Vo ts 4.8 Vo ts 2.0 Vo ts
B 3 3.0 Vo ts 3.6 Vo ts 1.5 Vo ts
B 2 2.0 Vo ts 2.4 Vo ts 1.0 Vo ts
B 1 1.0 Vo ts 1.2 Vo ts 0.5 Vo ts
C 1 5.0 Vo ts 6.0 Vo ts 2.5 Vo ts
C 2 7.0 Vo ts 8.4 Vo ts 3.5 Vo ts
C 3 8.0 Vo ts 9.6 Vo ts 4.0 Vo ts
C 4 9.0 Vo ts 10.8 Vo ts 4.5 Vo ts
C 5 10.0 Vo ts 12.0 Vo ts 5.0 Vo ts
Available Modes
On arriva , the IC is set to MODE 1A. Re-trigger is set to ON.
CT = MIDI C ock
The bottom 7 rows indicate which MIDI channe s the outputs respond to, the ower 3 showing overf ow behaviour to next
chip if chained.
Mode 4PV receives notes on MIDI channe 1 and a ocates them to an avai ab e output automatica y.
CT = MIDI C ock. Pu se ength = 1ms. Produces 24 pu ses per quarter note e.g. 48 pu ses / second @ 120 B.P.M.
Pitch Vo tages.
Vo ts / Octave Moog scheme: Output
MIDI key Value (hex) Value (decimal) 1V / oct 1.2V / oct 0. V / oct
---------------------------------------------------------------------------------------------------------------
A0 15 21 0.00 0.00 0.00
A1 21 33 1.00 1.20 0.50
A2 2D 45 2.00 2.40 1.00
A3 39 57 3.00 3.60 1.50
C4 3C 60 3.25 3.90 1.625
A4 45 69 4.00 4.80 2.00
A5 51 81 5.00 6.00 2.50
A6 5D 93 6.00 7.20 3.00
A7 69 105 7.00 8.40 3.50
A8 75 117 8.00 9.60 4.00
There is disagreement about MIDI key number standards. We used a free MIDI too ca ed MIDI Ox to disp ay va ues
from the contro er keyboard.
http://www.midiox.com
Port D – aux gates
e.g, in Mode 1A, pins D2, D3, D4 and D5 are aux gates and are triggered on
MIDI channe 16 by p aying notes C3 (60), C#3 (61), D3 (62) and Eb3 (63).
Midi channel 16
PORT - Midi note
D1 60
D2 61
D3 62
D4 63
Changing Modes
Mode change is enab ed by sending MIDI program change 99.
Then the desired Mode can be sent as MIDI program change
e.g. Mode 1A = program change "0".
Program # MODE
==================
0 1A (defau t)
1 1B
2 2A
3 2B
4 4A
5 4B
6 6
7 0A
8 0B
9 4PV
10 4MV
Examp e
To change to mode 4B:
send 0xC1 fo owed by 0x63 (decima 193, 99)
then send 0xC1 fo owed by 0x05 (decima 193, 5)
Hex Decima
===========
0xC1 193 Program Change
0x63 99 Enab es Mode Change (unti IC is powered down)
0xC1 193 Program Change
0x05 5 5 = mode 4B
There are MIDI fi es on the midimuso website to make this easier to do.
You don't have to reset the IC after a Mode change and the IC wi remember it is in the
new mode even after power off. The mode can be changed again at any time.
Parts List
Resistors:
Qty Va ue
12 100K R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14
1 10K R17
2 220R R1, R15
1 1k R16
1 5k R2 Trimmer / potentiometer
Capacitors:
1 1uf C3
2 22pf C16, C17
6 100nf C1, C2, C18, C19, C20, C21
12 10nf C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15
Crystal:
1 16MHZ
Semiconductors:
1 4N35 OK1 Optocoup er
1 L78M05CV IC3
1 LM317 IC2
3 LM324N U1, U4, U5
2 MC14504 U2, U3
1 CV-12 uContro er
Connectors:
1 DC Jack J1
1 5 pin DIN MIDI socket X1
1 3 way header, sing e row + jumper
3 8 way header 2 x 4 pin
IC Sockets:
2 16 pin
3 14 pin
1 28 pin
1 6 pin
Power supp y vo tage: 12 vo ts DC
Power supp y current: 500 mA minimum
Pitch reso ution ~ 0.03 semitone
Ana ogue outputs: 0 – 10 Vo ts
Gate outputs: 0 – 5 Vo ts
Continuity guide
Schematic
Table of contents
