Aphex Systems 2020Mk II User Manual

11068 Randall Street
Sun Valley, CA 91352, USA

Tel: 818-767-2929 • Fax: 818-767-2641
www.aphex.com

SM

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The Compellor provides a clean consistent sound when used as 
a pre-processor   

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Remote controllable relay hardwire bypass

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Fader settings are less critical and the sound of the station will 
not change from announcer to announcer

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For television, level changes between programs and commercials 
will be smoothed out without affecting audio quality

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Servo balanced XLR in/outs for maximum audio quality

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Cable television operators can offer consistency in level when a 
customer switches between channels

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Two channel Frequency Discriminate Leveler varies its attack time   

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Dynamic Verification Gate prevents pumping and breathing 
during short program pauses

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Dynamic Recovery Computer accelerates compressor recovery 
under complex program to preserve natural sound on transients

• Also available in mono with built in Aural Exciter™ - Model 323A

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The Aural Exciter increases presence, clarity, speech intelligibility 
and detail without distortion or overmodulation

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By pre-processing the audio, compensation can be made for the 
degradation the signal will receive further down the chain 

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Single-ended process that can be applied at any point in the 
audio chain before the peak limiter, and needs no decoding

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Total flexibility in “tuning” the Aural Exciter to your needs

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Patented Harmonic Generation Process can actually increase 
bandwidth without increasing level 

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Built-in single ended noise reduction can improve noisy sources

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Spectral Phase Refractor circuitry improves bass without eq.

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No unnatural distortion by-products

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Servo balanced XLR inputs and outputs for maximum audio quality

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Remote controllable relay hardwire bypass

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The Dominator provides an absolute peak ceiling adjustable in 
.2dB steps over a 34dB range. Equipment following the 
Dominator (STL,telco lines, stereo generators, uplink transmitters, 
etc.) may be driven to maximum input level without overload

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Model 722 is for applications requiring pre-emphasized limiting, 
such as STL’s, cable systems, satellite uplinks

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Greater consistency of peak audio levels, maximized S/N ratios, 
and highest possible resolution (more bits) in the digital domain   

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Patented Automatic Limit Threshold varies ratio of bandlimiting 
to clipping   

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Remote controllable relay hardwire bypass

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Switchable low to mid and mid to high crossover frequencies   

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Servo balanced XLR ins and outs for maximum audio quality     

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Model 722 - switchable pre- and de-emphasis, 50/75µsec/flat   

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Model 720 - flat only   

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104dB Dynamic Range

• The Model 720 is without emphasis circuitry at a lower cost

Aphex, Aural Exciter, Big Bottom, Compellor, Digicoder, Dominator, Easyrider and Expressor 
are trademarks of Aphex Systems, Ltd. All Aphex Products are ETL listed or pending.

The Model 2020MkII contains the following proprietary circuitry: Four Band Wave Dependent Compressor,
Post Crossover Multiband Technique, Split Band Clipper, Parallel Path Digital Modulation Stereo Generator,
Phase Coherent Crossover, Drift Stabilized A/D Converter, Frequency Discriminate Leveler, Sticky Leveler,
Dynamic Verification Gate, Distributed Pre-Emphasis Filter, Split Band Optical High Frequency Limiter, Low
Distortion Overshoot Compensated Low Pass Filter.
The Model 2020/2020MkII, 320A/323A, 250, 720/722 are covered by one or more of the following patents:
4150253, 4578648, 4633501, 4843626, 4939471, 5115471, 5155769, 5334947, 5359665, 5422602,
5424488, 5450034, 5463695, 5483600, 5485077, 5612612, 5737432, 5848167, 5896458, 5898395 and
5930374. Other U.S. patents issued and/or pending.

For detailed specifications on these or any other Aphex products call, fax, e-mail or write us.
Aphex reserves the right to make changes to its products without prior notice.            Rev:04-15-01  5k

Loading an output with multiple devices may cause
noise, distortion and reliability problems. Y-cords and
splitters are not the solution, a high quality distribution
amp is. The Model 120A has one-input with four inde-
pendent outputs. The inputs and outputs are trans-
formerless and servo-balanced, allowing interface with
balanced or unbalanced equipment (or even a dead
short) without affecting the other outputs.

Interfacing a -10dBV unbalanced device with a +4dBu 
balanced device must be done properly to avoid level mis-
matches, noise, and distortion problems. The Model 124A has
four discrete channels, two channels are -10dBV inputs to
+4dBu outputs and two channels are +4dBu inputs to -10dBV
outputs. The -10dBV outputs are active for low impedance
and the +4dBu inputs are transformerless servo-balanced, 
allowing the interface to be transparent and problem free.

Aphex is proudly American.... 100% owned,
engineered and manufactured in the U.S.A.