Enclosure not stated · 3 knobs

Bearfoot FX Pale Green Compressor

Based on the BearFoot FX Pale Green Compressor· 3 other boards clone it

Category: Compressor
Controls: Volume · Tone · Comp
Price: see vendor
Tags: freestompboxes.org trace

Read the post at Revolution Deux Schematic image freestompboxes.org thread

From the vendor

The Bearfoot FX Pale Green Compressor, an exact replica of the BJFe Pale Green: a light, transparent optical compressor. A 5534 op-amp gain stage has an LDR in its feedback loop; a transistor envelope follower driving the LDR's LED sets the gain reduction. A dual-gang Tone pot adjusts the EQ both before and after compression. The post says it is a simplification of the Mad Professor Forest Green Compressor, and the schematic is modified from Whitekeyhole's Forest Green trace.

With the Comp knob at minimum it works as a booster/enhancer/EQ. The Tone control's zero point is at noon: turning left gives a classic Dyna/Ross EQ, turning right adds treble and sparkle. Runs on 8 to 18V.

Schematic

The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.

Parts list 48 rows

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Check before you build · 4 values the reader of this schematic was not sure of

The schematic is marked NOT VERIFIED.
The drawing's own box says the resistor values are uncertain and differ between two Forest Green boards: R7 4.3K, R8 7.5K, R9 51K, R11 14.7K(?), R19 33K, R23 215R, R27 51K, against the values drawn (R8 1K, R9 147K, R11 56K, R19 47K, R23 285R, R27 147K; R7 is not drawn).
The 100p compensation capacitor on IC1 has no designator; it is listed as Ccomp.
The LDR part number is drawn as P50067 with a question mark.

Ref	Value	Normalized	Type	Notes
Resistors 22
R1	1M	1M		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
R8	1K	1k		7.5K on one board; read from the schematic by eye
R9	147K	147k		51K on one board; read from the schematic by eye
R10	147K	147k		read from the schematic by eye
R11	56K	56k		14.7K? on one board; read from the schematic by eye
R12	5.6K	5.6k		read from the schematic by eye
R13	200K	200k		read from the schematic by eye
R14	200K	200k		read from the schematic by eye
R15	10K	10k		read from the schematic by eye
R16	110	110		read from the schematic by eye
R17	110	110		read from the schematic by eye
R18	5K	5k		read from the schematic by eye
R19	47K	47k		33K on one board; read from the schematic by eye
R20	10K	10k		read from the schematic by eye
R21	22K	22k		read from the schematic by eye
R22	22K	22k		read from the schematic by eye
R23	285	285		LED resistor; 215R on one board; read from the schematic by eye
R27	147K	147k		51K on one board; read from the schematic by eye
R28	27K	27k		read from the schematic by eye
R29	27K	27k		read from the schematic by eye
Capacitors 13
C2	22u	22u		electrolytic; read from the schematic by eye
C4	1u	1u		electrolytic; read from the schematic by eye
C5	100n	100n		drawn as electrolytic; read from the schematic by eye
C6	1u	1u		read from the schematic by eye
C7	1u	1u		electrolytic; read from the schematic by eye
C8	22u	22u		electrolytic; read from the schematic by eye
C9	100n	100n		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
C14	1u	1u		electrolytic; read from the schematic by eye
C17	47n	47n		read from the schematic by eye
Ccomp	100p	100p		op-amp compensation, pins 5-8; no designator drawn; read from the schematic by eye
Diodes 3
D1	1N914	1N914		read from the schematic by eye
D2	1N914	1N914		read from the schematic by eye
D4	1N4007	1N4007		polarity protection; read from the schematic by eye
Transistors 3
Q2	BC550C	BC550C		read from the schematic by eye
Q3	BC550C	BC550C		read from the schematic by eye
Q4	BC550C	BC550C		read from the schematic by eye
ICs 2
IC1	NE5534	NE5534		JRC5534DD; read from the schematic by eye
IC2	78L05	78L05		5V regulator; read from the schematic by eye
Potentiometers 3
Volume	B50K	B50k	Potentiometer	read from the schematic by eye
Tone	A20K	A20k	Potentiometer	dual gang, A and B sections 20KA; read from the schematic by eye
Comp	A500K	A500k	Potentiometer	read from the schematic by eye
LEDs 1
D3	LED	LED		5mm red, inside the optocoupler; read from the schematic by eye
Other 1
LDR	P50067	P50067		LDR, part number uncertain; read from the schematic by eye

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