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.
Fig. 2: Arion SCH-1 chorus board
Specifications:
- 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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