Arion SCH-1 Stereo Chorus pedal schematic

The Arion SCH-1 is one of the best sounding vintage analog choruses, producing an incredible variety of authentic tones, anything from subtle, clean chorus to a pretty realistic Leslie effect. It was not popular back in the 80s when it was launched, but over the years it has built up a good reputation and acquired devoted users, including some of today's leading guitar players. Although it's long discontinued, you can still spot a used unit on various online stores. Despite the plastic case and fragile construction, it's quite expensive - they usually sell for over $100 on eBay.

Schematic diagram of Arion SCH-1 Stereo Chorus pedal
Fig. 1: Arion SCH-1 Stereo Chorus guitar pedal schematic diagram

Arion SCH-1 Stereo Chorus PCB (PCSCH10B) - component side
Fig. 2: Arion SCH-1 chorus board

Arion SCH-1 Stereo Chorus pedal picture


  • 3 Control Knobs: Rate, Depth, Tone
  • Connectors: Input, Out1, Out2, AC Adaptor
  • Input impedance: 240kΩ
  • Output load impedance: over 10kΩ
  • Maximum input level: -4.5dB (0dB = 1V)
  • Maximum output level: -3dB
  • Residual noise level: -53.5dB
  • LFO speed: 1.8s - 90ms
  • Current Draw: 16mA (DC 9V)
  • Weight: 330g
  • Dimensions(mm): 73(W) x 50(H) x 127(D)

ICs, transistors and diodes used in the Arion SCH-1:

  • IC1, IC2: 6458D or TA75558P (Dual operational amplifier)
  • IC3: LA6358 or TA75358P (Dual operational amplifier)
  • IC4: MN3207 (1024 stage BBD)
  • IC5: MN3102 (BBD driver)
  • IC6: D4027BC or TC4027BAP (Dual J-K Master/Slave Flip-Flop)
  • Q1-Q3, Q5, Q7-Q9: 2SC1815 or equivalents (NPN silicon transistors)
  • Q4, Q6, Q9: 2SK772, 2SK445 or equivalents (N-Channel JFET)
  • D1-D6: 1N4148 or equivalents (switching diodes)
  • ZD1: 5.1V Zener diode

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