looking for a quality BNC female to RCA male adaptor

The Purist Audio adapters all seem to be $150 plus each, which is kind of expensive just for an "adapter".  I have found that the Black Cat BNC-to-RCA adapters are excellent and are only $30/pair:

https://www.blackcatcable.com/collections/accessories/products/black-cat-bnc-rca-adaptors

They have the best resolution compared to every adapter I have tested.  The gold-plated adapters that come with the Nordost cables (and that you can get cheap on ebay) are nice and they warm up the sound some to give the cable a little more engaging sound, but they mask resolution in the end.  The Black Cat adapters do not mask resolution, but it may be too revealing on a cable that could be a little bit sterile.

The Canare adapters aren't good at all in my opinion.  They sound extremely warm and the high frequencies are soft and a mess (great if you like that sonic signature -- like listening to a warm Parasound amp).

Thank you auxinput!  Is there anyone out there who has a Nordost adapter that they don't need?  Many of the Nordost digital cables come terminated with BNC and include two BNC to RCA adapters so you have options.  I am going to my local audio store today and ask if they might have one laying around.  Thanks, Jim

What did you end up using here?

You could order the Black Cat from The Cable Company and send it back if you didn't like it...