FX30B Gate/Loop

Two original-series FX30B Gate/Loop pedals,
from late 1985 ("Delay") and early 1987 ("Release")

The FX30B Gate/Loop replaced the FX30 Noise Gate in DOD's lineup in 1985, adding the utility of a built-in effects loop or as a switch between two instruments (one plugged into the INput jack, one plugged into the RETURN jack). Like the FX30, the FX30B (at least initially) used a LM358N for the noise gate portion of its circuit. Unlike the Boss NS-2, which probably became the FX30B's main competitor upon its introduction in 1987, the FX30B could not be used to power other pedals with a daisy chain (although the pedalboards DOD offered already included a power supply). The FX30B was discontinued in 1994.

• Controls (late 1985-86): Delay, Gate, Sensitivity
  
  
• Controls (late 1986-94): Release, Gate, Sensitivity
  
  
• Using the FX30B: The FX30B is not necessarily intuitive to use, and while DOD's website did not include its user manual, DiscoFreq kindly provides a scanned copy at his website (see below for link). The function of each of the FX30B's controls is summarized below, but we recommend that you peruse the manual as well:
  
  
  • To use the FX30B as a noise gate, start with the Sensitivity knob fully counterclockwise (which disables the noise gate), then slowly rotate the Sensitivity knob clockwise until the noise disappears when no signal is present (the LED will dim when the Gate is closed).
    
    
  • The Delay or Release knob adjusts the time required before the noise gate closes after the signal falls below the sensitivity threshold, between 5 milliseconds and 1-2 seconds (depending on which part of the manual you read).
    
    
  • The Gate control determines which input signal is monitored for noise (from the IN jack or the RETURN jack, or a combination thereof). Unless you are using the FX30B's loop, it is best to leave this control all the way counterclockwise ("IN"); with this setting, operation of the FX30B is the same as the FX30. Conversely, if you have a really noisy pedal chain within the FX30B's loop, you should turn the Gate knob fully clockwise ("RETURN").
    
    
• "Delay" vs. "Release" variants: The original FX30Bs followed the FX30's control names, Delay and Sensitivity. The FX30B's Delay control was renamed Release in late 1986, possibly to help ensure buyers weren't confused into thinking the FX30B was a delay pedal.
  
  
• Technical info:
  
  
  • Specifications (circa 1986): IN and RETURN impedance = 500 k Ohms, OUT and SEND impedance = 1 k Ohms; S/N Ratio > 90 dB; Bandwidth = 40 Hz to 20 kHz
    
    
  • Official schematic provided with pedal by DOD (11/27/85)
    
    
  • Notable IC chips (through at least 1987): LM358N low power dual bipolar op amp (used in the noise gate section), plus a LF353 op amp
    
    
  • Component-side circuitboard images: Dec. 1985 Feb. 1987
    
    
  • Related circuit: 225 Master Switch
  
  
• FX heritage: FX30 FX30B
  
  
• External links:
  • @ discofreq's FX site includes a copy of the FX30B's manual
  • @ harmony-central.com
  • @ noiseguide.com
  
  

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