EFM VCO 3D User manual

VCO 3D
Dual VCO based on the
Moog Rogue oscillators.
Features...
●Two wide range VCOs
●Saw and Varable PW
●Syncable
●On board chip heater
may be disabled in
favor or 1K tempcos
●+/-12 or +/- 15V
The VCO3d is supplied with tempco resistors however there is a chip-heater option on
the board.
Chip-Heater
To use the chip-heater option the three spaces on the board marked for TC , TC and TC-
R are not used. All parts and jumpers are installed. Turn the unit on. After about five
minutes warmup adjust trimmer R7 until U5 pins 5 and 6 are equal. About +0.67VDC.
Tempco Resistors

To use the tempco option the three spaces on the board marked for TC , TC and TC-R
are used.
Unused or changed parts
●Install (2) 1K tempco resistors for the spaces marked TC. Leave enough slack on
the leads so that they can be placed in contact with the top U1. Use a little heat sink
compound to insure good thermal contact.
●Install a 1K resistor for TC-R
●Omit R6, R40, R41, R42, R43, T-7
●Change R44 from 33-ohm to 10K
●Remove the tiny jumper to the left of TC-R that connects U1 pin-14 to +V
●Jump C8 (.01uF)
Setup
You will need a way to generate keyboard control voltage, a tuning refernace, monitor
amplifier and a way to mix the vco outputs into the amp.
●Hook the saw output of VCO1 up to the monitor amplifier
●Hook your 1v/Oct controller to KCV-VCO1 and KCV-VCO2
●Turn on the amp and make sure that it's turned down
●Apply power to the vco board
●Turn the amp up to a reasonable level
●Turn Freq and Fine controls for both VCOs to 12 o'clock.
●Play the middle octave on your controller. Usually C4-C5.
●Adjust T2 until the VCO's middle C is close to the frequency of your referance
keyboard.
●Play the C4-C5 octave and adjust T1 until the octave is correct.
●Play the higest octave on your keyboard and adjust T3 until the octave is correct
●Turn up the level on VCO2's output
●Play middle C and adjust T5 until the VCO's are close to the same frequency
●Turn the level on VCO1 down
●Play the C4-C5 octave and adjust T4 until the octave is correct.
●Play the higest octave on your keyboard and adjust T6 until the octave is correct
●Turn up the level on VCO1 to balance the ocillators outputs adjust VCO2 to match
VCO1 as close as possable while checking your tuning referance.
●Wait for a while and do it all again to tighten thing up.

Full Parts Kit
C1,C2, 0.1 2
C3,C5,C7,C8 0.01 4
C4,C6 100p 2
R1,R20 22K 2
R2,R19,R21,R25,R13,R14,R16
R18,R21,R32,R33,R35,R37,R40 100K 14
R3,R22 330K 2
R5,R24,R42 47K 3
R6,R25 1K 3
R,R267 1K 2
R8,R27,R43 4.7K 3
R9,R11,R12,R15,R28,R30,R31,R34 10K 8
R10,R29 20K 2
R17,R36 2.2K 2
R4,R23,R39 1M 3
R41 3K 1
R42 51K 1
R44 33 1
D1 1N914 1
Q1,Q2 2N3906 2

U1 LM3046 1
U2,U3,U4,U5 TLO72 4
PC-Board 1
Small Parts Kit
P1,P3 50K 6
Knobs 6
T4,T6 10K 4
T1,T3,T2,T5 50K 2
1/8 PHONE 12
L-Bracket 2
Power Connector 1
8 pin 4
14 pin 2
Panel 1
Overlay Overlay 1