XLR to RCA adapter

[brad1138]

I have found a number of forum posts in various forums that say pin 3 line should be cut when going from an XLR out to RCA in. Less stress on the op amp I believe (might be something else). I can not find an XLR -> RCA adapter or cable that allows you to open up the XLR connector to make the alteration.

Any suggestions? It will be connected to the Main XLR outs of a Marantz AV7705 prepro. (I know it has RCA outs also, long story)

[Whitneyville1]

The "theory" is to avoid ground loops which CAN be an issue with "PRO AUDIO" to RCA connections. Sometimes lifting pin three helps, sometimes it hurts. Bitter experience talking. I just hope your AC outlets are correctly wired as to polarity or you'll have a 60Hz buzz that you'll go INSANE tracking down, or I nearly did! Watch keeping your balanced to unbalanced cables well separated too. I had to build a jig to keep them apart to avoid "coupling" noises. Best of luck!

[fpitas]

I would not connect pin 3 to ground like that, either. I can't see that it helps anything, and it will pointlessly short the - output. But I have no experience (good or bad) trying to do what you're doing.

One of the right ways to do that is through a transformer. Unfortunately good ones aren't cheap.

[billfitzmaurice]

The issue is that RCA is an unbalanced signal, XLR is a balanced signal, so you should transform from the one to the other, either with a transformer or electronically.

[Paul O]

So why can't you use the RCA output on the Marantz?
There is no advantage to using the XLR output in this case, this is not a balanced connection and won't have any of that formats noise rejection properties.. if that is what you were thinking.

[wogg]

Ignoring why you'd want to do this... That schematic will work, but I would not connect the shielding to the RCA side ground. The shielding will be grounded on one side, providing minimal EMI protection, and the +- signal will be transmitted to the RCA without shorting either side. This requires the RCA side equipment to be floating, so NO 3 prong power cords anywhere.

It'll work fine, not as ideal as a transformer or active balanced to single ended circuit, but functional nonetheless.