OK I'm trying to understand the comment "going to replace". What are you using now?
With regards to AES/EBU to SPDIF, been there done that. I decided to get a converter and convert the coax to optical and then optical to the device. With the differential to single ended coax I didn't like what I saw on my digital oscilloscope and I seemed to be getting a lot of bit errors. This effect will be more pronounced on a longer cable run, so if it's short you may not have an issue. It's been long enough ago I might have built this, don't remember.
With newer stuff, just level conversion is probably good enough.
If you want to know way more than you need to about this issue, here is a great reference article. https://www.rane.com/note149.html
They also describe multiple schemes to achieve level conversion.
Oh and if you use the Neutrik solution mentioned above make sure to consider the cable ends, as the Neutrik is BNC and sounds like your device has a RCA plug.