DCI Specialty audio line level hum eliminator device on a wooden surface.

Audio Hum Eliminator

The ALH1 Audio Hum Eliminator Removes Hum and Buzz between Audio Components or Computers 
Price Including Free Standard Shipping: $47.50

Eliminates HUM in Stereo & Home Theater Systems
Professional grade performance- Line Level up to 100 feet
Computer, Subwoofer, TV, Cable Box, CD, Stereo, Home Theater System, Remote Location
No bandwidth limitation- Frequency Response all the way to DC
*Adjustable Controls
*Stereo Input/Output
*Freq. Response- DC-100KHz +/-0.2db
*Insertion Loss- 0db
*RCA Jacks
*Includes Output Cable
*Includes UL-Listed AC Supply

What Does the ALH1 Audio Hum Eliminator Do?

The ALH1 Audio Hum Eliminator eliminates hum in Stereo and Home Theater Systems. Components in different locations are most susceptible. Hum results from slightly different ground potentials at the power plugs. Long audio cables exasperate the problem. The ALH1 Hum Eliminator will cancel hum up to 2.5 volts-plenty of capability to handle common ground-related hum up to several hundred feet in length in a building (typically up to 20mv). The ALH1 Hum Eliminator cannot correct for defective audio cables or defective AC power wiring or connectors. Also, performance is only assured with modern 3-prong grounded receptacle wiring.

Diagram of DCI Specialty ALH1 Hookup with detailed component connections.

How Does the ALH1 Audio Hum Eliminator Work?

The ALH1 is an active electronic circuit that cancels hum by processing only the difference between the signal and the shield ground, effectively cancelling hum on the shield ground by injecting an opposite polarity hum signal. The signal remains true and unmodified, and has the same output level as the input. Independent controls are provided for tuning the circuit to the individual type and length of cable. The ALH1 Hum Eliminator is unlike an isolation transformer, which has insertion loss (drop in signal level), poorer frequency response, and greater distortion across the frequency band. Transformers can provide massive quantities of common-mode rejection at higher voltages, but that is rarely what is needed in a home audio system. Also, a quality transformer needs complicated winding and is therefore expensive. The ALH1 delivers the highest performance audio quality.

What Components Can Be Used With the ALH1 Audio Hum Eliminator?

You can use the ALH1 to connect TV Line outputs, Cable Box Line outputs, Computer Sound Card outputs, CD Players, Tape Players, Stereo or Home Theater Line outputs, and other sources to the Line Input of Stereos or Home Theaters or other amplifiers. The interconnect cables can be up to several hundred feet long.

How Do You Adjust the ALH1 Audio Hum Eliminator?

Because all electrical wiring and audio installations are different, the DCI Specialty ALH1 Adjustable Audio Hum Eliminator has an adjustment for each channel to tune it to your specific installation. Simply turn the adjustment control for minimum hum.

DC power supply with red and white cables connected on a wooden surface.

How Does the ALH1 Audio Hum Eliminator Compare With Other Products?

A comparison of other types:

DCI Specialty ALH1 Stereo Electronic Circuit Yes- Independant Channels DC to 100khz +/-0.2db <0.01% DC to 100khz 0db @ 1khz 40db $65.00
Jenson CI-2RR Stereo Isolation Transformer No 20 to 20khz -0.03db/-0.7db 0.25 to 50khz -3db 0.04% @ 20hz <0.001% @1khz 0.82db @ 1khz 95db @ 60hz 85db @ 3khz $177.95
Radio Shack 270-0054 Stereo Isolation Transformer No 300-4,000hz +/-3db Not Stated Not Stated Not Stated $16.99

Comparison Summary

The DCI Specialty ALH1 has a significantly better flat-frequency response across the entire audio band. It also has lower distortion, and higher output than both.

The Jenson unit exceeds the ALH1 only in CMR. However, the ALH1 does suppress hum 40db (1/100'th of its original level), which is WAY down there.

The Radio Shack unit has a frequency response that is barely better than speech quality, and being a consumergrade transformer circuit, distortion, and insertion loss are predicatively high.

The DCI Specialty ALH1 provides professional-grade audio performance at a reasonable price.

ALHI Testimonials

Over the years, we've received some very entertaining emails from customers. These emails were unsolicitated.

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Reviews

See Reviews of the ALH1 Audio Hum Eliminator at:

Secrets of Home Theater and High Fidelity

Home Theatre Forum

AVS Forum