FX80B Compressor Sustainer

Three 'original series' cosmetic variants of the FX80B,
from early 1986, mid 1987, and late 1988 (left to right)

The FX80B Compressor Sustainer was introduced in mid-1985, and replaced the FX80 in DOD's FX-series lineup. The FX80B added a third knob to control how quickly the signal is compressed, allowing the user to have more dynamic control of the effect. With the introduction of the FX84 Milk Box in 1996, DOD effectively discontinued production of the FX80B, although one FX80B has been seen with a serial number corresponding to early 1998.

• Controls (1985-87): Level, Attack (5-200 ms), Compression (0-40 dB)
  
  
• Controls (late 1987-on): Level, Release, Compression
  
  
• From the manual (shared with the FX82): "The FX80B Compressor/Sustainer ... 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."
  
  
• Catalog descriptions:1987 1991
  
  
• Attack vs. Release variants: Like the FX82, 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 from 1987 were identical (including the listed specifications) except for the name of the knob.
  
  
• Instruction manuals: At least three different covers/versions of the instruction manual exist: (left-right) mid 1980s, late1980s/early 1990s, early/mid 1990s. The latter two versions were shared between the FX80B and FX82, with a 1987 copyright date; aside from the front cover and the name of the middle knob (see above) they are identical, with exactly the same content.
  
  
• Technical info:
  
  
  • Specifications (1985-86): Input impedance = 500 k Ohms, Output impedance = 1 k Ohms; Compression Range = 35 dB; Attack Time = 5 ms; Release time = 150 ms; Bandwidth = 40 Hz-16 kHz; Signal-to-noise Ratio = 90 dB
    
    
  • Specifications (1986-87): Input impedance = 500 k Ohms, Output impedance = 1 k Ohms; Maximum Input Level = 4 V P-P; Compression Range = 0 to 40 dB; Attack Time = 5 to 200 ms; Release Time = 150 ms; Bandwidth = 40 Hz-16 kHz; Signal-to-noise Ratio = 90 dB; Gain = variable +/- 12 dB
    
    
  • Notable IC chips: RCA CA3094E OTA (1986), RCA CA3080E OTA (1987-88 and beyond?); TL022CP (through 1987?) or MC1458 op-amps
    
    
  • Component-side circuitboard images: February 1986 May 1987 November 1988
    
    
  • Related circuit: FX82
  
  
• FX heritage: FX80 FX80B FX84
  
  
• External links:
  • @ ftp.dod.com - instruction manual (1987), .pdf format
  • @ discofreq's FX site
  • @ harmony-central.com
  • @ noiseguide.com
  
  

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