Q2 Audio Compex F765 500 Series Compressor Stereo Pair

Manufactured by Q2 Audio in close collaboration with Audio & Design, the F765 Compressor/Limiter Module is a remake of the classic F760-N module and has now been adapted to the 500 series modular rack system. It is authentic in every detail and reproduces the exact sonic qualities of the original product.

Using the original discrete analogue circuit design employing a feedback FET technique and maintaining the use of the same components that give this product such a distinctive sound, the new F765 compressor/limiter will add dynamic punch to your sound as well as controlling peak excursions.

The original F760-N module was used by major recording artists worldwide throughout the 60s, 70s, and 80s. This famous, iconic processor was instrumental in shaping the sounds of that era. Now as the F765 it returns to take a worthy place in the ever-popular 500 series rack system with it’s unique signature on the sounds of today.

Features

• Single channel level control offering simultaneous compression gain reduction with peak limiting
• Precision calibrated compressor/limiter threshold control which allows the user to “dial up” the amount of compression required before peak limiting occurs
• Switched Compression values from 1:1 (amplifier), 2:1, 3:1, 5:1, 10:1 & 20:1 (limiter)
• Auto dual platform release function – allows fast transient recovery on a “build-up” slow release

Specifications

• Input: 10K ohms Unbalanced
• Output: Transformer Balanced (Cinemag CMOB-3L) Max output: 20dBu, 18.5dBm
• Metering: Sifam Fast Responding analog meter
• Stereo Linking: Must order as stereo pair
• Power requirements: +/-16V DC @ 70mA per rail (brief 400mA turn-on surge).
• System Gain: 34dB with input/output attenuators fully open. Unity gain in Bypass mode
• Thresholds:
  • Peak Limiter: +14dBu maximum with unattenuated output. Referred to unattenuated input level 20dBu
  • Compressor: Calibrated with reference to Peak Limiter thresholds and marked 0 – 20dB in 2dB steps. (Reference to unattenuated input level this is -20dBu to -40dBu)
• Release:
  • Peak Limiter: 250mS,
  • Compressor: 25mS, 50mS, 100mS, 200mS, 400mS, 800mS, 1.6 secs, 3.2 secs + Auto release function
• Attack:
  • Peak Limiter: < 250uS for 100% control of overshoot – without any over limiting. (measured at 1KHz for 10dB gain reduction)
  • Compressor: 250uS, 2.5mS, 25mS
• Distortion: Measured at 1KHz for 10dB compression & 3.2 secs release time.
  • Compressor: at +10dBu threshold <0.1% (typically 0.04%)
  • Peak Limiter: at +14dBu threshold <0.3%
• Frequency Response:
  • Balanced: < -0.5dB at 20Hz & < -0.75dB at 20KHz
• Signal – Noise Ratio: Referred to Peak Limiter threshold level as set by output attenuator: better than -80dB (Measured with low pass filter -3dB at 25HKz)
• Stereo Matching:
  • Control volts matching on compressor to within ±1dB of each other, consequently no image shift during operation
  • Selectable Peak Limiter operation
  • Peak Limiter on – off or Pre-emph (50uS time constant)
• Indicators:
  • Overall Gain Reduction Meter scaled 0 – 20dB in 4dB divisions. White scale on black background with yellow pointer
  • Peak Limiter operating: Red indicator

Enhancements

• Gold contact rotary switches
• Gold contact toggle switches
• Conductive plastic potentiometers
• PCB headers for possible future connection to E900 type EQ
• Sidechain Insert and Bus output functionality per Radial Engineering specs
• Sidechain insert is jumpered by default
• Sidechain insert send minimum external load of 10K

Please note: stereo pairs must be ordered as such. Attempting to stereo link two random units is not advised.

Word on the Street:

"Q2 Audio's F765 is a single-channel 500 module version of the compressor and limiter sections of Q2 Audio's reissue of the two-channel ADR Compex Limiter F760X-RS that originally came out in the late '60s. It is amazing that all that functionality and power is contained within the confines of a single slot 500 module and still have room for a GR meter! I'm sure if it were a two-space module it could also have the original's Gate/Expander with all its controls and features too.

None-the-less, the F765 as is has the sound and color of the original 2U Compex processor. The F765 succeeds well as an excellent compressor/limiter for any source from raucous vocals to boring drum recordings. It is a well-made quality piece of gear that, after initial setup, is easy to get solid operation.

I just love my pair here in the rack and I use them on every mix."

Barry Rudolph