Random*Source SERGE NCOM, Quick Start Manual

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2

Serge ÷N COM

Bill of Materials

The following values are suggestions and may deviate from other / older versions of the ÷N COM: - this is DIY! 

Resistors (1%)

2 10R

F1, F2

alt: FERRIT BEAD

2 OMIT

R2, R18

* do not install *

1 330R RS

R26 - marked "RS"

install 330R + 100R trimpot for the 5.15 voltage source

3 330R

R25, R31, RS

2 2k2

R1, R9

1 15k

R16

2 33k

R11, R27

alt: 10k + Zener Diodes (see below)

4 47k

R4, R6, R7, R8

2 51k1 (47k)

R13, R15

1 110k

R5

1 121k (110k) R14
7 249k

R3, R10, R12, R21, R22, R23, R24

1% or better - ideally closely matched

1 499k

R20

1% or better

1 1M

R19

1 6M8

R17

1 100R

TS (Precision Voltage)

Trimpot (Bourns 3362P or anything that matches the 
footprint) to adjust the Voltage to 5.156V - or any value 
that yields the desired 1V/Oct scaling of the stepped output 
(tune sending the stepped output into the 1V/Oct input of 
an oscillator). Use a good DMM and 

measure between the 

two test pads (“- TEST -”)

.

Capacitors

1

47p*

C*

Use larger value e.g. 1nF,

 I used 220p which 

seems to work nicely, too. 

9 100n

C3, C4, C5, C6, C7, C8, C9, C10, C11

Bypass caps

2 10uF

C1, C2

Electrolytic (or 22uF) >= 25V, 2.5mm ls

ICs

2 4559

U2, U5

NJM4559D or RC4559P

2 2N3904

Q1, Q2

NPN Transistor

1 CD4093BE

U1

Quad 2-input NAND schmitt trigger

1 CD4520BE

U4

Dual binary up COUNTER

1 LM317LZ

U6

Positive VOLTAGE REGULATOR

1 LT1009C

U7

Precision Shunt

2 ZENER 4.7V

D1, D2

Optional: Zener Diodes as CMOS input protection 
Install “4V7” if you use 10k for R11, R27.