Pearl FG-01 Flanger schematic

The FG-01 Flanger is a long discontinued pedal from the Pearl Sound Spice series, with a wide range of delay time (1.8ms-20ms), generating not only the typical flanging sound, but also chorus, phaser and short delay. It has four knobs: Speed, Depth, Manual and Feedback.

Schematic diagram of Pearl FG-01 Flanger
Fig. 1: Pearl FG-01 Flanger guitar pedal schematic diagram

Operating instructions from the FG-01 Flanger user manual:

Control Knobs:

Manual: Used to select the frequencies to be given flanging effect. Turning clockwise selects high frequency range, and counterclockwise selects low frequency range. This control is also effective for modifying tone color.

Feedback: Used to emphasize the characteristic flanger sound. Turning clockwise heightens effect.

Depth: Adjusts the depth of flanging effect. Turning clockwise gives deeper and wider effects.

Speed: Adjusts the speed of flanging effect. Turning clockwise increases speed.

Typical settings:

1. A setting for a natural flanging effect (effective with arpeggio or chord backing):
Manual: 8, Feedback: 5, Depth: 4, Speed: 3.

2. A setting for phasing:
Manual: 9, Feedback: 3.5, Depth: 2.5, Speed: 5.

3. A setting for chorus:
Manual: 5, Feedback: 0, Depth: 4, Speed: 4.

4. A setting for metallic sounds (e.g. ring modulator):
Manual: 6, Feedback: 10, Depth: 0, Speed: 1.

Pearl FG-01 Flanger picture


  • 4 Control Knobs: Speed, Depth, Manual, Feedback
  • Connectors: Input, Output, AC Adaptor
  • Input Impedance: 1MΩ
  • Output Impedance: 10kΩ
  • Maximum Input Level: -4dB (0dB=775mV) at 440Hz
  • Input Switching Noise: -98dB (IHF-A)
  • Delay Time: 1.8ms-20ms
  • Modulation Speed: 0.08Hz-10Hz
  • AC Adaptor: AC-90, VR-5
  • Current Draw: 11.5mA (DC 9V)
  • Weight: 490g (including battery)
  • Dimensions(mm): 79(W) x 57(H) x 136(D)

ICs, transistors and diodes used in the Pearl FG-01 Flanger:

CH-2 main circuit board:

  • IC1, IC2: TL062CP (dual operational amplifier)
  • IC3: MN3207 (1024 stage BBD)
  • IC4: MN3102 (BBD driver)
  • IC5: TL022CP (dual low-power general-purpose operational amplifier)
  • Q1: 2SC2240GR (NPN silicon transistor)
  • Q2,Q3,Q4: 2SC1815Y (NPN silicon transistors)
  • D1,D3,D4: 1S1588 (switching diodes)
  • D2: UZ-5.1B (5.1V Zener diode)

SW-1 switching board:

  • IC1: MC14007UB (Three N-Channel and P-Channel complementary pair and inverter)
  • Q1,Q2: 2SC1815Y (NPN silicon transistors)
  • D1,D2: 1S1588 (switching diodes)
  • D3: Red LED
  • D4: MA522 (Lambda diode)

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