Aphex Systems 320A owner manual

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320A

Compellor

There are basically three ways to attack the prob - lem of a ground loop. First is to eliminate it from its source, and the second is to re-route it through another path. The third is to balance out your unbal - anced audio interfaces.

Identify the Sources

A good way to identify grounding problems is to use a multimeter to check the ac voltage between the chassis of your various gear when no audio cables are hooked up and all gear is plugged in and switched on. Just start touching the two probes to the metal chassis of di￿erent pieces of gear. Ideally, you should always see zero volts. Warning! You may see as much as the whole line voltage between two di￿erent chassis! It does happen. This voltage between chassis will be responsible for your ground loop problems. If you ￿nd there is more than about 1 volt between equipment grounds, you should start looking for a remedy.

Commonize the Power

Try plugging all of your equipment into the same outlet strip. Get one that has enough outlets in one strip or string more than one together. Of course, you need to make sure you don’t overload the one ac cir - cuit your strip is plugged into. If the load is too great for one circuit, use a second or third circuit that is tapped o￿ the same 120 volt phase in your distribu - tion panel. That means all outlets should be on odd or even numbered circuit breakers. That’s because, as you go down the column, the circuit breakers tap into alternating legs of your incoming electric power. Be sure you’re always on the same leg. You can tell you’re on the same leg by measuring the ac voltage between the hot slots of the di￿erent outlets you’ve chosen. It should be very low or zero. That will remedy 50 percent of the cases.

Check the Cord Polarity

For products that have 2-wire power cords, try revers - ing one of the power cords in the socket. That may reduce the ground current generated by the internal electronics of the o￿ending gear.

Redirect Ground Loops

Sometimes it just comes down to brute force ground - ing. That means providing such heavy, low resistance, ground current paths that little current is left to ￿ow through your audio grounds. You can try adding heavy gauge, for example 12 gauge, copper wire

from chassis to chassis. You will need to locate a metal screw that solidly binds to the metal chassis of the gear. You may even need to drill a hole through the chassis and install a screw yourself. Equipment in rack shelves can have their chassis grounded to the metal rack frame by a heavy wire and the frame itself can act as a brute force ground. You just have to try everything you can think of. Usually a combination of all these methods will be needed to completely clean up a badly humming audio system.

Balance Out the Audio

Remember, balanced lines are inherently hum free. If you can balance out your unbalanced equipment, you will be able to stop the hum.

Pseudo Balancing

You will ￿nd in Appendix D an interconnecting method called Pseudo Balanced. This works when connecting an unbalanced output to a balanced input. This breaks up the ground loop by requiring the shield to be grounded only at one end. For best results always ground the shield only at the receiving end.

Level Interface Units

Aphex manufactures the Model 124A Level Interface box which is designed to electronically convert two unbalanced inputs and outputs into two balanced inputs and outputs, and at the same time translate the -10dBV IHF unbalanced levels to the pro +4dBu balanced levels. This cost e￿ectively gives your non- professional unbalanced equipment a fully profes - sional I/O equal to the world’s best pro audio gear. Seriously consider putting one of these on each unbalanced piece of gear you use.

Avoid Transformers

The use of balancing transformers is an option, but you will invariably lose audio quality due to trans - former limitations. Try everything else ￿rst.

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Contents 320A Safety Declarations Fast Finderi320A Contents Page Quick Start Quick StartWhat Is a Compellor? What Does It Do?How Does It Work? Bit Of Compellor HistoryIntroduction Page Damage & Claims UnpackingMains Voltage Selection And Fuse Power Cord Safety ConsiderationsMounting In a Rack Proper VentilationInstallation Remote ConnectorReference Level Setting Input ConnectionsSummary Specications Ratio Introduction RecordingMixing MasteringLive Concerts Video Post-ProductionBroadcast Radio Pre-processing Broadcast STL/ Phone Line Driver Television Broadcasting and Cable SystemsVideo and Audio Tape Duplication Voice ProcessingHard Disk Recording Processing Functions Signal FlowLeveling Function Compressor Function DRCDVG Silence GateStereo Enhance Stereo LinkingMeter Selections LimiterProcess Switch Output ControlInput/Output Operating LevelsGain Reduction Metering Limited Warranty To Obtain ServiceAppendices Appendix B 320A Appendix C Proper Wiring Techniques Appendix CAppendix D Appendix D Part 1 Balanced OUT to BalancedImpedance Balanced Outputs Part 5 Y Insert Cables Appendix E Appendix E Compellor to the RescueWhere The Problem Comes From Appendix FConfusion PPM StandardAppendix F VU StandardWhere The Compellor Fits Death of a Perfectly Good VU MeterBirth of dBFS DAT TragedyIdeal Audio Package Analog/Digital Level DiscrepancyWhat, Me Worry?

320A specifications

The Aphex Systems 320A is a dynamic processor designed to enhance the quality of audio recordings in professional settings. Known for its exceptional performance and versatility, the 320A offers a unique combination of compression, limiting, and expansion functionalities. This unit is an essential tool for sound engineers and producers looking to achieve polished sound.

One of the standout features of the 320A is its dual channel processing capability. This allows users to apply dynamic processing to two separate audio signals simultaneously, making it ideal for stereo or dual mono setups. The 320A offers a range of controls, including threshold, ratio, attack, release, and gain, allowing precise adjustments to be made according to the needs of any project.

The 320A utilizes Aphex's proprietary Intelligent Clipping technology, which helps to prevent distortion at high signal levels. This feature is particularly beneficial when working with dynamic sources like vocals and percussive instruments. Intelligent Clipping ensures that the audio remains smooth and clear, even when processed aggressively.

In terms of connectivity, the Aphex 320A is equipped with balanced XLR and TRS inputs and outputs, ensuring compatibility with various audio sources and devices. The unit supports both line-level and mic-level signals, providing flexibility for different recording scenarios. Additionally, its low noise operation ensures that the final output retains pristine audio quality.

Another significant characteristic of the 320A is its user-friendly interface. The front panel features easy-to-read meters and clearly defined controls, making it straightforward for users to monitor the audio levels and adjust settings in real-time.

The 320A also includes a sidechain capability, allowing users to trigger compression or expansion from an external source. This feature is useful for achieving effects like ducking or creating rhythmic dynamics in a mix.

In summary, the Aphex Systems 320A is a feature-packed dynamic processor that serves as an invaluable tool for audio professionals. With its dual channel processing, Intelligent Clipping technology, flexible connectivity options, and user-friendly design, the 320A stands out in the realm of audio processing equipment, delivering high-quality performance for a variety of recording and mixing applications.
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