RCA to XLR adapters?

Kirk, thanks very much for another of your exceptionally knowledgeable big-picture perspectives, which certainly makes a persuasive case for the conclusion expressed in your last paragraph.

The Cardas adaptors we have seen do not do anything with pin 3

It amazes me how so many manufacturers, both pro-oriented and audiophile-oriented, seem to have it backwards when it comes to rca-to-xlr adapters. Rca to xlr-female adapters, which would be used on xlr outputs, should leave pin 3 unconnected, but almost invariably ground it to pin 1. Rca to xlr-male adapters, which would be used on xlr inputs, should ground pin 3 to pin 1, yet here we have an example of a respected high-end manufacturer leaving pin 3 open.

Best regards,
-- Al

I think most of the responders here have missed the Question . Bobheinatz wants to use a single ended ( 2 wire cable ) in a balanced set up , Which will require a 3 wire cable . You can use adapters or reterminate , but you won't get a balanced signal with a 2 wire cable .

12-16-10: Tmsorosk: I think most of the responders here have missed the Question. Bobheinatz wants to use a single ended ( 2 wire cable ) in a balanced set up , Which will require a 3 wire cable . You can use adapters or reterminate , but you won't get a balanced signal with a 2 wire cable.

The discussion has focused mainly on the EFFECTS of putting an unbalanced signal into a balanced amp, so I don't think the question has been missed.

12-15-10: Kirkus: A common example is this notion of a "balanced amplifier" being simply two amps stuck in a chassis wired to different pins of an XLR connector. In this instance (as you correctly postulated) any voltage imbalance between the two amplifier stages will disturb the necessary null for cancellation of even-order harmonic distortion products. And this voltage imbalance will be affected by any impedance OR voltage imbalances in the preceeding equipment, cables, or the input termination resistances . . . not to mention any differences in gain, distortion performance, or bandwidth between the two amplifier stages.

I think it's also worth noting that using an adapter to put an unbalanced signal into that kind of design would result in up to 75% of the amplifier's power capability being unable to be utilized, since the voltage swing capability between the two output terminals would be cut in half.

Best regards,
-- Al

Almarg ... I'm aware of where the discussion went , I just don't think we helped out the poster much , probably confused him as much as I .

Ralph,

The protection circuit issue with the ARC amp may be weird, but it doesn't mean the amp needds to be fixed, either. I learned of the issue not because I had a problem, but because I called ARC before I even tried the approach. They explained the issue to me as an inevitable result of the amp's design. Now, it may not be broken, but that doesn't mean you have to like the design.

Of course, it is possible that I "misremembered" the explanation, but I don't think so.

Marty