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When peaks exceed this ceiling, gain is reduced to keep peaks within specified limits. The amount of gain reduction, attack and release times, and the output gain matching are all precise and independent adjustments. This makes the CL-50E and the CL-52E extremely useful for such diverse applications as loudspeaker protection, broadcast limiting or compression, recording, tape-to-disc transfer, special effects, vocal level control, and musical instrument sustain. The two important components of any limiter are the VCA (Voltage Controlled Amplifier), which actually performs the function of reducing gain, and the detector, which essentially tells the VCA what to do, i.e. when to reduce reduce the gain and by how much. On the surface, it might seem like the VCA is the most critical component, since audio actually passes through it while the detector merely provides it with a DC control voltage, but experience has shown us that both are crucial to the overall sound. The VCA in Ashly’s Compressor/ Limiters represents a new generation of integrated circuits that offer exceptionally low noise and distortion figures, flat frequency response, freedom from thermal drift and excellent reliability. Audio signals passing through the VCA emerge clean and uncolored. The detector has the task of monitoring incoming audio levels and changing the gain of the VCA as determined by the set- tings of the front panel controls. The detector in Ashly’s Compressor/Limiters is a fully symmetrical peak responding type, and includes a 'send-return' loop which allows frequency selective limiting and other effects. The detector must constantly adjust the gain of the audio path in a manner which keeps the level under control while still sounding acceptable to the listener. This constantly changing gain is a dynamic action, while conventional audio measurements like noise and distortion checks are static (constant level). This led us to use a purely subjective approach in the design of the detector; we did a lot of listening to determine what sounded good and what didn't. As a result of this research, we designed the detector to allow the attack and release times to speed up as more and more limiting occurs (the compression ratio also increases), and we utilized a double-release time constant to minimize 'pumping' and 'breathing'. The result is a natural-sounding compressor/limiter that responds very well to a wide variety of audio applications. The CL-50E is Ashly's single channel compressor/limiter. The CL-52E is essentially two CL-50E’s in one rack space, but it offers improved metering and switching. The CL-52E can be used as a stereo compressor/limiter or as two separate mono units. Ten-level meters are provided on each channel to indicate gain-reduc-tion and output level. The CL-50E and CL-52E compressor/ limiters, like all Ashly products, are now fully covered by Ashly's exclusive five-year worry-free warranty. Extremely Low Noise and Distortion Detector Patch Points for Frequency-Selective Limiting Gain Reduction Meters In-Out Bypass Switching Inputs and Outputs May Be Used Balanced or Unbalanced Unusually Wide Control Range on All Parameters Output Level Meters and Clipping Indicators (CL-52E) Front Panel Stereo Tie Switch (CL-52E) Specifications CONTROLS stereo tie switch (CL-52E ONLY) defeat switch gain: ±30dB ratio: 2:1—oo attack time: 200,u S. - 20m S. release time: 100mS - 2Sec. output: -40dBV - +20dBV Detector Patch Point: allows the connection of an EQ for frequency selective limiting Maximum Input/Output Level: +20dBm Input Impedance: 10ks.2 balanced bridging Output Impedance: 50Q term, w/ 60012 or more Frequency Response: ±.2dB 20Hz - 20kHz Distortion: <.015% THD, OdBV 20 Hz - 20kHz, no limiting <.15% +18dBV worst case Hum and Noise: -95dBV unity gain Power Requirements: 120 VAC, 50-60HZ, 5W Size: 19" L x 1 3/4"H X 6"D Shipping Weight: 8lbs M Block Diaaram- GAIN BALANCED INPUT 1 O- RATIO ATTACK RELEASE CONTROL DETECTOR IN OUT • PATCH — VCA OUTPUT LEVEL GAIN REDUCTION METER DISPLAY OUTPUT LEVEL METER DISPLAY V u OUTPUT Many interesting and productive effects can be achieved by combining the CL-50E or the CL-52E with Ashly's SG-33E or SG-35E Noise Gates. Architect s Specification The unit shall be a single [CL-50E) or dual (CL-52E) channel compressor/limiter with indepen' dent attack, release and ratio adjustments. It shall have detector patch points which allow connection of an external equalizer In the detector loop to produce frequency selective limiting. It shall have front panel mounted switches for engaging/ defeating the compressor/limiter functions. Performance specifications of a typical production unit shall meet or exceed the following: Gain control shall be i30dB. The ratio shall be adjustable from 2:1 to «=. The attack time shall be adjustable from 200fiJS to 20mS. The release time shall be adjustable from lOOmS to 2 seconds. The output shall be adjust...