Serge Sequential Pulse Source

Serge Sequential Pulse Source

Basic 10-step sequencer based on CD4017 decade counter



Bill of materials


One of the most popular and popular means of creating control signals in block-modular sound synthesis systems are sequencers. They allow you to quickly solve the problem of creating repetitive rhythmic patterns based on pulsed clock signals. This project will serve as a lesson for those who are going to understand the essence of this type of modules and how they are arranged. The project is based on a five-step Johnson CD4017 divider counter, with ten decoded outputs, which will allow you to create the simplest 10-step sequencer.

The sequencer circuit was developed by Sergey Cherepnin and was released as a Serge system module under the “R16 Sequencer” index since 1973. Its various options can be found in collectors and fans in the form of originals and remakes. An unpleasant feature of this module is the lack of an internal clock source, however, you need to understand that, historically, this module went along with the Serge programmer under the “PRG” index.

This module used a single +6 V power bus, effectively setting the output voltage to about 5 V. The output of this module from the Serge product line was probably related to the failure of the +6 Volt power bus in later devices using only +12 and - 12 volts.


Project schematics / Serge Sequential Pulse Source
Title Version Creation date Copyright notice Software Download link
Schematics of the Sequencer (version 0.9)

Schematics of the Sequncer (version 0.9)

0.9 9/14/2018 Serge Tcherepnin DipTrace Schematics Download PDF
External connections schematics (version 0.9)

External connections schematics (version 0.9)

0.9 12/18/2018 Serge Tcherepnin DipTrace Schematics Download PDF
Simulation / Serge Sequential Pulse Source
Title Version Creation date Copyright notice Software Download link
Симуляция работы секвенсора
1.0 12/20/2018 Делосский Водолаз LTspice IV Download file

Bill of materials

Sequencer Core (version 0.9)
# Value Quantity Designator Comment
1 1N4148 2 D2, D1
2 BC550 11 Q10, Q11, Q12, Q2, Q4, Q5, Q6, Q7, Q8, Q9, Q1
3 BC560 1 Q3
4 CD4017 1 U1
5 L78L06 1 U2
1 15k 4 R10, R30, R8, R7
2 10k 10 R12, R14, R16, R18, R20, R22, R24, R26, R28, R1
3 330R 10 R13, R15, R17, R19, R21, R23, R25, R27, R29, R2
4 1k 2 R4, R3
5 22k 2 R6, R5
6 10R 1 R11
7 33k 1 R9
1 47pF 1 C1
2 10nF 1 C2
3 47uF 1 C3
4 100nF 1 C4
5 0.33uF 1 C5
1 2.54/10P 1 J1
2 3.96-2P 1 J3
3 2.54/5P 1 J4
Serge Tcherepnin
Serge Tcherepnin

American composer and electronic-instrument builder