Enclosure not stated · 3 knobs
Mad Professor Forest Green Compressor
Based on the Mad Professor Forest Green Compressor· 2 other boards clone it
- Category
- Compressor
- Price
- see vendor
- Also as
- Vero layout · from Revolution Deux
- Tags
- freestompboxes.org trace
From the vendor
An optical compressor whose basic building block is the Ibanez CP-830: an AD797 op-amp stage with an LDR and the Comp pot in its feedback loop, a BC550C side chain with a 1N914 rectifier driving the LDR's LED, and a 2SK170 JFET / BC560C output stage. A switch selects compressor or sustain mode, and a Tone control fine-tunes the compressed sound.
The drawing lists a second set of values ('FGC_CB_VALUES') for another board version: op-amp JRC5534DD with 100p between pins 5 and 8, C1 22n, C5 100n, C6 1u, C8 4u7, C12 1u, C15 1u, C16 100u, R5 43K, R7 4K3, R8 7K5, R9 51K, R11 14K7 (queried), R19 33K, R23 215R, R25 5K6, R27 51K. That board version uses a different tone circuit: two 20KA pots ('Tone' A and B) on a dual control. ShortScaleMike's vero (image 7) is unverified; the post asks builders to report back.
Schematic
The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.
Parts list 62 rows
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Check before you build · 1 value the reader of this schematic was not sure of
- The LDR is not given a part number.
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 29 | ||||
| R28 | 27K | 27k | read from the schematic by eye | |
| R29 | 27K | 27k | read from the schematic by eye | |
| R2 | 1M | 1M | read from the schematic by eye | |
| R3 | 5.6K | 5.6k | read from the schematic by eye | |
| R1 | 1M | 1M | read from the schematic by eye | |
| R8 | 1K | 1k | read from the schematic by eye | |
| R7 | 2.4K | 2.4k | read from the schematic by eye | |
| R18 | 5.6K | 5.6k | read from the schematic by eye | |
| R12 | 5.6K | 5.6k | read from the schematic by eye | |
| R9 | 147K | 147k | read from the schematic by eye | |
| R6 | 2M | 2M | read from the schematic by eye | |
| R24 | 470 | 470 | read from the schematic by eye | |
| R4 | 10K | 10k | read from the schematic by eye | |
| R25 | 16.9K | 16.9k | read from the schematic by eye | |
| R5 | 130K | 130k | read from the schematic by eye | |
| R26 | 1M | 1M | read from the schematic by eye | |
| R27 | 147K | 147k | read from the schematic by eye | |
| R11 | 56K | 56k | read from the schematic by eye | |
| R10 | 147K | 147k | read from the schematic by eye | |
| R22 | 47K | 47k | read from the schematic by eye | |
| R21 | 22K | 22k | read from the schematic by eye | |
| R20 | 10K | 10k | read from the schematic by eye | |
| R15 | 10K | 10k | read from the schematic by eye | |
| R13 | 200K | 200k | read from the schematic by eye | |
| R14 | 200K | 200k | read from the schematic by eye | |
| R16 | 110 | 110 | read from the schematic by eye | |
| R17 | 110 | 110 | read from the schematic by eye | |
| R19 | 47K | 47k | read from the schematic by eye | |
| R23 | 285 | 285 | LED resistor; read from the schematic by eye | |
| Capacitors 17 | ||||
| C2 | 22u | 22u | electrolytic; read from the schematic by eye | |
| C1 | 47n | 47n | read from the schematic by eye | |
| C17 | 47n | 47n | read from the schematic by eye | |
| C3 | 47p | 47p | read from the schematic by eye | |
| C5 | 1u | 1u | electrolytic; read from the schematic by eye | |
| C8 | 22u | 22u | electrolytic; read from the schematic by eye | |
| C4 | 1u | 1u | electrolytic; read from the schematic by eye | |
| C9 | 100n | 100n | read from the schematic by eye | |
| C6 | 220n | 220n | read from the schematic by eye | |
| C15 | 220n | 220n | read from the schematic by eye | |
| C12 | 22u | 22u | electrolytic; read from the schematic by eye | |
| C16 | 22u | 22u | electrolytic; read from the schematic by eye | |
| C7 | 1u | 1u | electrolytic; read from the schematic by eye | |
| C14 | 1u | 1u | electrolytic; read from the schematic by eye | |
| C10 | 100n | 100n | read from the schematic by eye | |
| C11 | 100n | 100n | read from the schematic by eye | |
| C13 | 22u | 22u | electrolytic; read from the schematic by eye | |
| Diodes 3 | ||||
| D4 | 1N4007 | 1N4007 | supply protection; read from the schematic by eye | |
| D1 | 1N914 | 1N914 | read from the schematic by eye | |
| D2 | 1N914 | 1N914 | read from the schematic by eye | |
| Transistors 5 | ||||
| Q1 | 2SK170 | 2SK170 | JFET; read from the schematic by eye | |
| Q5 | BC560C | BC560C | read from the schematic by eye | |
| Q4 | BC550C | BC550C | read from the schematic by eye | |
| Q2 | BC550C | BC550C | read from the schematic by eye | |
| Q3 | BC550C | BC550C | read from the schematic by eye | |
| ICs 2 | ||||
| IC2 | 78L05 | 78L05 | read from the schematic by eye | |
| IC1 | AD797 | AD797 | read from the schematic by eye | |
| Potentiometers 3 | ||||
| Comp | A500K | A500k | Potentiometer | read from the schematic by eye |
| Tone | A20K | A20k | Potentiometer | read from the schematic by eye |
| Level | B50K | B50k | Potentiometer | drawn VOL; read from the schematic by eye |
| Switches 1 | ||||
| Sustain | SPST | SPST | compressor/sustain; read from the schematic by eye | |
| LEDs 1 | ||||
| D3 | LED | LED | 5mm red; read from the schematic by eye | |
| Other 1 | ||||
| LDR | ? | ? | LDR; read from the schematic by eye | |
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