RCA to XLR Adapter

Hi,
Use single ended only or balanced only. Adaptors are not such a good idea for sound quality no matter how fancy they look.

@ebm  +1
I use the Neutrik between my HT Processor and the subwoofers.
Loosing sound quality there is not that important. 

ebm6 is correct - adapters in the path will degrade SQ

Concerning the “mixing and matching” connecting single ended to balanced or the reverse - some degradation can occur. 
My cables are the adapter - XLR on one end, RCA one the other. My balanced gear is forgiving - some is not😡 As I posted, one day better cables w/better connectors. Better ingredients better 🍕😊. 

You will always loose sound quality with adapters no matter how good.I think you best bet is to look at an amp that does single ended well such as PASS etc. 

https://www.neutrik.com/en/product/na2f-d2b-tx
https://www.neutrik.com/en/product/na2m-d0b-tx
I use them without any issues.
you have XLR male or female input choice.

If you make your own, be patient, twice check your connections, and try one channel at a time. 
If you get hum, obviously something is incorrect, check again😊
Been there, ”doing that,” satisfied w/the results. One day I’ll upgrade the cabling. Right now too many other, bigger fish to fry. 
Tony

@almarg Thank you for the thorough and helpful reply.  

The section of the Moon Audio writeup cautioning against using adapters is talking about a completely different situation. There is no risk of damage in using RCA-to-three pin XLR adapters at the input of a power amp, and connecting RCA cables between the preamps’s outputs and the adapters. Of course, sonics most likely won’t be as good as if you were providing the amps with a balanced pair of signals for each channel.

There are a few preamp designs, especially some of those having transformer-coupled outputs and some others in which the outputs are "floating" relative to circuit ground, in which a hum might result from doing that. But that would be unusual and is not applicable to this case.

The need for caution usually arises when adapting XLR outputs to RCA inputs, not the reverse.

Also, you mentioned Cardas adapters. Like most other such adapters, most of those short pin 3 to pin 1, but some of them don’t. In this case I’m pretty sure it would be best to use the kind which shorts pin 3 to pin 1, which is what Cardas supplies as standard.

Finally, there are a few unusual designs, such as many or all of the Audio Research Ref series amps which only provide balanced inputs, for which using an adapter (and therefore not providing the amp with a balanced pair of signals) will result in a drastic reduction of the amp’s power capability, and an increase in distortion. I suspect that is NOT the case with the amps you are considering, as the ARC amps are unusual in that respect, but it would be prudent to check with the manufacturer on that point. If that turns out to be a problem, a pair of suitably chosen Jensen transformers (together costing ca. $300) connected between the preamp and the amps would provide the amps with a true balanced pair of signals for each channel, and resolve that problem.  And the Jensen transformer approach is very likely to be better in terms of sonics than an adapter approach in any event.

Regards,
-- Al

Make sure the amp is wired in the usual pin 1 ground, pin 2 +, pin 3 - 

https://www.amazon.com/Monoprice-XLR-Male-RCA-Cable/dp/B001UJH0XU?th=1

You just need to find out the wiring of the pins on your amplifiers input and have a cable made or modified. My preamplifier (Doshi, not full balanced circuit anyway) has XLR out and I called the distributor for the information. My amplifiers are RCA.

Moon-Audio's site says, "Balanced adapters are always a bad idea for single-ended cables because they can damage your gear."
https://www.moon-audio.com/blog/balanced-audio-always-better?gclid=CjwKCAjw7-P1BRA2EiwAXoPWA-1hDXu2b9-vCCsy8-tVD_Mw6dY2QpIcofGL4pTgAs681YwXFH-3oRoCRz8QAvD_BwE   z

I'll take their word for it and avoid going that route.

May be downsides to asking the question here tho... ( couldn't resist:)  You can always terminate IC cables with XLR on one end which I did in one case. Otherwise Miller is correct as usual!

You mean besides the cost, the additional connection, and the loss of balanced in a component whose whole reason for being is being balanced? No. Not a one.