Frequency Central XVCO Build Documentation

Frequency central
Build documentation for:
xvcO
Based on the Roland System 100M VCO.
XVCO has at it's heart a transistor array chip, usually a CA3046. These are getting a little harder to
source recently, so this PCB has the option to instead use a surface mount LM3046*. Alternatively,
the eastern European UL1111 can be substituted. This PCB incorporates an onboard chip heater for
the transistor array chip.
* If using a surface mount transistor array substitute the 18K resistor for 2 x 33K resistors in parallel.
Key to PCB screen print:
n: This signifies NPN BC547 transistors. Note the correct pinout as shown by the half circles.
p: This signifies PNP BC557 transistors. Note the correct pinout as shown by the half circles.
f: This signifies 2N5485 FETs. Note the correct pinout as shown by the half circles.
The PCB shows the correct orientation for BC547/BC557. Other transistor types can be used
(eg 2N3904/2N3906), but please observe the correct pinout. Please observe the correct
polarity of the electrolytic capacitors.