I think I will get an RCA to xlr converter until I get the real thing. Seems like these are available from pro-audio shops.
Given the previous comments by Docknow (thanks!) and myself, I assume you are referring to an active converter, i.e., one that contains powered circuitry. If so, a point to keep in mind is that like many and probably most ARC line stages and preamps the input impedance of the device to which the SP9 MkII is connected should be relatively high. From its description at www.arcdb.ws:
Recommended load 60K ohms and 100pF. (20K ohms minimum)
A lot of pro audio equipment will not meet that requirement, not even the 20K minimum.
A transformer-based converter, by the way, such as the Jensen I referred to earlier, will easily meet that requirement when used in conjunction with your particular power amp, and when used with many and probably most other amps as well.
Regards,
-- Al