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R/E/P => Mastering Dynamics => Topic started by: Thomas W. Bethel on January 13, 2015, 08:22:12 AM

Title: AES/EBU cables ground on one end or both?
Post by: Thomas W. Bethel on January 13, 2015, 08:22:12 AM
I bought some pre-made AES/EBU Apogee cables a while back. They were only grounded on the female end. Most of my AES/EBU cables that I make myself are wired the same way. Just wondering what the the correct way? The reason I did my cables the way I did them was for preventing ground loops. I have seen articles on the WWW saying that they should be grounded at both ends. Anyway what are you doing and why? Thanks in advance.
Title: Re: AES/EBU cables ground on one end or both?
Post by: Jim Williams on January 13, 2015, 11:13:20 AM
AES is a balanced signal, it doesn't need a ground connection except as a shield. That's why it's connected at one end, that provides the shielding without creating a potential ground loop.
Title: Re: AES/EBU cables ground on one end or both?
Post by: Jim Wilson on February 02, 2015, 03:23:56 PM
Hi Thomas. Although there really isn't an official consensus, I have always heard "lift Pin 1 (ground) on the input" side of every connection. This way, the shield is connected to the audio ground of the output device.  EMI and RFI are less likely to be picked-up by the input of the receiving device following this rule. I do this for all of my balanced connections, analog and digital. With digital interconnects, we don't have the "luxury" of hearing noise or hum on the connection. The connection will either pass a valid signal or not.
Furthermore, I recommend that you check all of your digital interconnect from time to time by passing a 192kHz signal through all of your connections via your router or otherwise.  Often, there are weak connections that can pass 96kHz and lower signals without interruption, but if you go to 176.4 or 192, you might experience loss of lock.  This happened in my studio, and was due to some bad solder joints in a few terminations.  Once repaired, there was a noticeable improvement to the audio at all sample rates.  To repeat a famous quote from Bob Ludwig, "Never Turn Your Back on Digital!".