Descripción
The Q2 Audio F765 is the compression and limiting sections of the famous «Compex Limiter»™ built into a single 500 Series slot. The audio path contains the same blue Phillips type capacitors and BC series transistors as the original Compex.
Formatted after the vertical «N-Unit» with slight layout changes for enhanced usability, the F765 lives up to the reputation it’s big brother, the F760X-RS, has made over decades of being a «secret weapon» on countless records.
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
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
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 ordered as stereo pair for proper stereo performance
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
Sound on Sound: "The classic sound of the ADR Compex... in API Lunchbox™ format".
Barry Rudolph for Music Connection Magazine: "...the F765 as is has the sound and color of the original 2U Compex processor."
Geoff Stanfield, TapeOp May/June 2017: "The F765 is a solid utility compressor and a creative tone machine all in
one.... this processor can knit elements
together while really adding something special to the mix."
