Frequency Central System X Filter Build Documentation

Based on the roland system 100m vcf

Build documentation for:

System X filter

Based on the Roland System 100M VCF

Frequency central

Version 2 / April 2013

B100K

A100K

B100K

A100K

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. D, S, G is

signified should you want to sub alternatives.

Gnd: Ground

Please observe the correct polarity of the 2 diodes and 12 electrolytic capacitors. The 10 x

22uF are configured in sets of 2 back to back (negative to negative).

Table of Contents

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Page 1 Build documentation for: System X filter Based on the Roland System 100M VCF Frequency central Version 2 / April 2013 B100K B100K A100K B100K A100K A100K Key to PCB screen print: n: This signifies NPN BC547 transistors. Note the correct pinout as shown by the half circles.
Page 2 The PCB shows the correct orientation for BC547/BC557/2N5485. Other transistor types can be used (eg 2N3904/2N3906/BF245), but please observe the correct pinout. Thermistor (next to 5K6 resistor) I use a 10K NTC available from Tayda, seems perfect: http://www.taydaelectronics.com/thermistors/10k-ohm-ntc-thermistor-5mm.html …but, you can just use a 10K resistor if 100% temperature stability isn’t so important to you. I can assure you, it’s pretty accurate anyway without the thermistor.
Page 3 Underside of the PCB showing: Ground bus between sockets and PCB Connections between inputs/outputs and PCB I use solid core for all of the above. RDH 17 May 2013 http://www.frequencycentral.co.uk/...