RCA to XLR - How bad are the current crop of adapters ?

I do, so much appreciate the responses thus far. I am sorry if I mislead anyone, as I should have been more specific and detailed about my inquiry. I have actually been listening to the amplifiers for a few weeks now, with a pair of inexpensive cables I had purchased off the Bay ( $10., shipped ), locking male xlr to male rca. I like the amplifiers very much, but I am attuned to using much better cables, and I do hear the weaknesses and limitations of these cables. I am not needing to go balanced, as my passive pre is very close to the amplifiers. The amplifiers are by Kelmar Systems, model 120 +, removed from a movie theater. The front panels say " United Artists Communications ". These are, basically, Hafler 220 amplifiers, but, on steroids. I have a few other " theater " amplifiers around my house ( all removed from movie theaters ), under the name Smart Theater Systems, which use barrier strips for the inputs and outputs, also designed around the Hafler circuits and chassis. My understanding is, Hafler did a lot of this kind of business (  before Fosgate got involved ). Back to these mono amps. I am having zero impedance or voltage issues, and, will actually spring for a good set of xlr / rca cables, because, after making this post, I have concluded, that these amplifiers, are definitely keepers, in a working system ( not sitting in my closet ). In fact, I am actually thinking, now, to send them out for upgrades / rebuilds, to someone such as Musical Concepts, or Jensens Stereo shop ( in my earlier days, I could do some of this work myself, accumulating the necessary parts ). If it has not crossed anyone's mind at this point, I happen to enjoy amplifiers using the original Hitachi mosfets. Sound wonderful through my horn systems ( I have many Hafler and Soundcraftsmen pieces I never sold during my closet clean outs, 2-3 years ago ). Anyway, thank you, again, for all of your attention and feedback. Always, and Enjoy ! MrD.

Hi MrD,

FWIW, if it were me I would perform the assessment of the amps using either the Neutrik adapter Jtcf suggested, or a similarly priced adapter offered by B&H Photo Video under their pro-oriented house brand "Comprehensive."

Consistent with Bob’s suggestion just above, if I decided to keep the amps I would then purchase a pair of single-channel Jensen transformers, which would convert each of the unbalanced signals into a pair of true balanced signals. The cost would be roughly $300 for the transformers plus the cost of a pair of very short XLR cables, assuming you already have suitable RCA cables having the necessary length.

I’ve used the Comprehensive adapters with fine results, btw, although in conjunction with a couple of relatively non-critical sources (a vintage Tandberg 3004 cassette deck and a vintage REL Precedent FM tuner, both of which are very highly regarded albeit within the limitations of their respective formats).

Finally, if by any chance the amps happen to be Audio Research models, be aware that many of their amps which are fully balanced **and which provide only XLR inputs** will not work properly if provided with unbalanced inputs via adapters or adapter cables.

Best regards,
-- Al

Only Jensen for me.
Bob

I've used Neutric adapters with no ill effects.$8 from Parts Express.

If it’s a temporary situation, I would buy these adapters. They are the best connectors! 

https://www.amazon.com/Cardas-Audio-Female-Adapters-FRCA-MXLR/dp/B00KVMCJIS/ref=pd_aw_sim_23_2/135-4...

Cardas makes the best. They have a Clear version and a regular version. They are $120 and $200 a pair. Expensive, but they are the best. The cheap adapters are different degrees of crap.