"Neutrik is often asked whether the shiny silver tab on typical XLR cable connectors should be connected to anything."
"In the course of the evolution of the AV industry, it has come to be that this tab is practically never terminated. This means, in turn, that the shell is not grounded. When in doubt, simply leave this tab unterminated."
"Whether or not they are internally wired to the shield signal, XLR cable connector shells always make an electrical connection to chassis connector shells once the two are mated."
"Typically, chassis connectors need to be grounded. The industry best practice is generally to tie all of the chassis connector shells, pin 1 (cable shields), and the enclosure shield to a common ground."
Neutrik USA Today - Grounding XLR connectors - Volume 6, Issue 2, June 2016
Additional Reading: AES48 - "AES standard on interconnections - Grounding and EMC practices - Shields of connectors in audio equipment containing active circuitry."
Note: Benchmark uses Neutrik cable and chassis connectors because of their superior performance and durability.
In accordance with these best practices outlined above, Benchmark bonds pin 1 of XLR chassis connectors directly to chassis ground. Benchmark leaves the cable tab unterminated on all analog XLR cables, but terminates this tab on AES digital XLR cables.
Benchmark recommends leaving the cable tab unconnected on all analog XLR cables.
Benchmark terminates the cable tab on AES digital XLR cables to minimize radio-frequency emissions when two or more digital XLR cables are connected end-to-end. Digital cables that do not have the tab terminated should not be daisy chained.
Benchmark recommends tying the cable tab to the shield on all AES digital XLR cables.
As an engineer I like to use "rules of thumb" to make quick estimates that help to explain the physical world around me.
These rules of thumb are easy-to-remember approximations that eliminate the need for complicated and needlessly precise calculations.
If you feel discombobulated by the complexities of high school physics, there is hope! I encourage you to step back and take a fresh approach.
If you learn a few simple rules of thumb, you can unravel mysteries of the physical world, amaze your friends, and yourself.
In this paper I will present 15 simple rules that I find useful when working with music and audio.
- John Siau
The Benchmark AHB2 power amplifier and HPA4 headphone amplifier both feature feed-forward error correction. This correction system is an important subset of the patented THX-AAA™ (Achromatic Audio Amplifier) technology. It is one of the systems that keeps these Benchmark amplifiers virtually distortion free when driving heavy loads. It is also the reason that these amplifiers can support 500 kHz bandwidths without risk of instability when driving reactive loads.
This paper explains the differences between feedback and feed-forward systems. As you read this paper, you will discover that you already understand the benefits of feed-forward correction because you use it instinctively to improve a feedback system commonly found in your automobile. If feed-forward correction can improve your driving experience, it may also improve your listening experience!
If you look at the back of any Benchmark product, you will find balanced XLR analog-audio connectors. As a convenience, we also provide unbalanced RCA connectors on many of our products. In all cases, the balanced interfaces will provide better performance.
We build our unbalanced interfaces to the same high standards as our balanced interfaces, but the laws of physics dictate that the balanced interfaces will provide better noise performance.
This application note explains the advantages of balanced interfaces.