Balanced Output to Unbalanced Input

I am very close to pulling the trigger on an Oppo BDP-95 Blu-ray player. Is there any benefit to using the XLR stereo outputs even though my Marantz SR7005 A/V receiver does not have such inputs? Is it worth buying XLR-to-RCA cables to take advantage of those connections?

Emmanuel Margetic

The short answer is no, there is no benefit to connecting balanced XLR outputs to unbalanced RCA inputs. Balanced connections are used to reduce the effect of noise induced by stray electromagnetic fields, especially in long cable runs. They include two signal conductors and a ground conductor, and the two signal conductors carry the same audio signal at opposite polarities as depicted above. Any noise picked up along the cable will presumably be at the same polarity in both conductors and thus rejected by the differential amplifier at a balanced input. Since there is no differential amplifier at an unbalanced input, any induced noise will not be rejected, and it will be amplified along with the intended signal.

Not only that, it's possible that connecting a balanced output to an unbalanced input might be detrimental to the signal, depending on the design of the balanced output stage. In most cases, the negative output of a balanced output can be connected to ground, but in some cases, it should be left disconnected. Assuming the Oppo player and Marantz AVR will be in close proximity to each other, I recommend using short unbalanced cables with RCA connectors on both ends in your case.

If you have an A/V question, please send it to askhometheater@gmail.com.

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COMMENTS
ialvarad's picture

RCA unbalanced vs XLR balanced when connecting the Marantz separates AV7005 with MM7055, can you tell the difference? any advantage? Thks

Scott Wilkinson's picture
You probably won't be able to tell the difference if the cable lengths are short. On the other hand, using XLR balanced connections between these two components adds a bit of assurance that no induced noise will slip into the signal. Also, it reduces the chance of ground-loop problems, though that depends on how the grounding of each component is designed.
kbn's picture

Thank you for this write up! Although, I did notice a tremendous difference between unbalanced and balanced cables when I was testing my Martin Logan Descent i via LFE. I'd really like to take advantage of the Line Level In on my two Descent's. The obstacle I'm having is the distance from my Mcintosh C50 to the sub woofers (roughly 15ft; 50ft in cable length to get rid of the eye sore). I was actually thinking the same about using a balanced cable to unbalanced adapter to conquer this. The only other option I can think of would be running RCA terminated RG6. So, a new question! Since RG6 does very well with low frequencies... how would either connection help or hurt what I've been seeking to accomplish?

CJLA's picture

At KBN, I think another option for you would be to pull Cat 5e/6 wire in the wall and use an audio balun (which stands for BALanced UNbalanced). This is what we use for installations of long wire runs where we need to carry audio video signals for long distances. If you think you need additional protection from EMI, you could use Cat 5e/6 shielded cable and connectors as well.

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