EQF 500™
  • 3-band semi-parametric EQ
  • Selectable peaking/shelving on high and low bands
  • Separate high pass and low pass filters
  • –20Hz to 20kHz range of adjustability

The EQF 500 is a three band semi-parametric EQ that includes independently selectable variable high and low pass filters. The high and low EQ bands can be switched between shelving and peaking. Illuminated buttons for all functions ensure the EQ’s state can be seen from a distance. The output of the EQF 500 is balanced with a Jensen JT-11DL output balancing transformer.

  • Bands: Low: 25Hz-500Hz; Mid: 250Hz-5kHz; High: 1kHz-20kHz
  • Cut/boost: +/-12dB
  • High pass filter at 20Hz – 500Hz
  • Low pass filter at 1kHz – 20kHz
PAR 500 Series Review
Pro Audio Review "Studio Review," October 2013


The EQF 500 reissue is our modern take on the classic Aphex EQF-2 500 series equalizer, originally developed around 1976.

The EQF-1 and EQF-2 were designed for API modular consoles. Aphex built the very first EQF-1 by hand, which led to a limited production run. The EQF-2 was then designed to include shelving EQ for both the high and low bands. History shows that the EQF-1 and EQF-2 were some of the very first 500 series modules released that were not made by API.

Fast forward to 2012 and the classic EQF-1 and EQF-2 modules continue to be highly sought after by 500 series enthusiasts. Our EQF 500 mixes a classic design with improved control layout and modern components for high headroom and low noise.

The EQF 500 is approved by the VPR Alliance.

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Type Transformerless, active balanced
Impedance: 40KΩ
Unbalanced 20KΩ
Nominal Level +4dBu
Maximum Level +24dBu
CMRR >40dB
Impedance 110Ω
Nominal Level +4dBu
Maximum Level +24dBu Unloaded
Frequency Response +0.5dB 10Hz-38KHz
Dynamic Range 120dB
THD 10Hz – 22kHz @ max output 0.0003
IMD 10Hz – 22kHz 0 max output 0.0007

All specifications are subject to change without notice.

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Owner's Manual

EQF 500 Owner's Manual

Promo Materials (click to download PDF)

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