FX82 Bass Compressor

Two 'original series' cosmetic variants of the FX82, from 1987 (left) and 1988

The FX82 Bass Compressor was based on the circuit for the FX80B Compressor Sustainer, but voiced for bass guitar. While both DOD and Boss introduced a line of effects pedals targeted specifically at bassists in 1987, the FX82 did not have a direct competitor in Boss' effects pedal line (although the Boss LM-2 Limiter, also introduced in 1987, also works well with bass). The FX82 was produced from 1987 to about 1996.

• Controls (early 1987): Level, Attack (5-200 ms), Compression (0-40 dB)
  
  
• Controls (late 1987-on): Level, Release, Compression
  
  
• From the manual (shared with the FX82): "The ... FX82 Bass Compressor reduce[s] the dynamic range of the input signal from an instrument. Dynamic range is the difference between the loudest and quietest portions of an instrument's sound. By "compressing" or squeezing the the loudest and quietest portions of an instrument's sound into a more compact range, you can control the signal better. Since the loudest and quietest portions of your notes are compressed, your notes sustain longer, the sounds seem tighter, and you can help avoid clipping going into other effects or your amplifier."
  
  
• Attack vs. Release variants: Like the FX80B, the middle knob of the original versions of the FX80B was labeled 'Attack,' to vary the time required before the compression would occur. Low Attack settings would thus allow initial transients to pass through without compression, enhancing the dynamic range. In late 1987, the middle knob was re-labeled 'Release', defined as the time required before the compression would release. It is unclear whether the difference was cosmetic or not, as two different FX80B/FX82 manuals with 1987 copyright dates were identical (including the listed specifications) except for the front cover and name of the middle knob.
  
  
• Technical info:
  
  
  • Specifications: Input impedance = 500 k Ohms, Output impedance = 1 k Ohms; Compression Range = 0 to 40 dB; Attack Time = 5 to 200 ms; Released Time = 150 ms; Bandwidth = 40 Hz-16 kHz; Signal-to-noise Ratio = 90 dB; Gain = variable +/- 12 dB
    
    
  • Notable IC chips: RCA CA3080E OTA (1987-??); TL022CP (through 1987?) or MC1458 op-amps
    
    
  • Component-side circuitboard images: July 1987 March 1988
    
    
  • Related circuit: FX80B
  
  
• External links:
  • @ ftp.dod.com - instruction manual (1987), .pdf format
  • @ discofreq's FX site
  • @ harmony-central.com
  • @ noiseguide.com
  
  

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