Boss CS-2 Compression Sustainer pedal schematic diagram

The Boss CS-2 Compression Sustainer effect was sold from December 1981 to June 1986. The pedal compresses high-input level signals while boosting low-input level signals, producing a smooth and long sustain without degrading the quality of the original guitar sound.

Boss CS-2 Compression Sustainer Pedal Schematic Diagram Fig. 1: Boss CS-2 Compression Sustainer guitar pedal schematic diagram
Boss CS-2 Compression Sustainer PCB (component side) ET5219-510A
Fig. 2: Boss CS-2 Compression Sustainer circuit board - component side
Boss CS-2 Compression Sustainer guitar pedal
  • Controls: Level, Attack, Sustain
  • Connectors: Input, Output, AC Adaptor
  • Input Impedance: 1MΩ (FET input)
  • Output Load Impedance: over 10kΩ
  • Compression Range: 38dB
  • Maximum Input Level: -10dBm at 1kHz
  • Maximum Output Level: -10dBm
  • Equivalent Input Noise: -110dBm (IHF-A)
  • Recommended AC Adaptor: ACA Series
  • Current Draw: 4mA (DC 9V)
  • Dimensions: 70(W) x 55(H) x 125(D)mm
  • Weight: 400g

ICs, transistors and diodes used in the Boss CS-2 pedal:

  • IC1: BA662A (VCA - Voltage Controlled Amplifier IC)
  • Q1, Q2, Q3: 2SK30ATM-Y (N-channel JFET transistors)
  • Q4, Q5, Q6: 2SC732TM-GR (NPN silicon transistors)
  • Q7-Q11: 2SC1815-BL (NPN silicon transistors)
  • D1: S5500G (400V/1A rectifier diode)
  • D2-D6: 1S2473 (switching diodes)
  • D7: RD5.1EB3 (5.1V Zener diode)
  • LED: SLP135B (red LED)