Identifying an Auditorium 23 Step up transformer


Hi, I have an Auditorium 23 Step up Transformer but don't know whether it is the high impedance version - for Denon 103, EMT etc, or the low impedance version for Ortofon SPU. There are no markings that indicate anything on the case. Can anyone help please? Mine has a black earth wire coming from its innards.
Thank You
rogerstaton
Great info dekay..I had both and don't recall. I can tell you the standard SPU and Denon versions are priced in line (if not the same) with one another. The EMT I believe is a fair amount higher in price, yet below the Homage T1 and T2. I have tried SUT's by a few manufacturers, and always preferred the A23. 
I have an Auditorium A23 SUT, designated/purchased for a Denon 103D, that does have a black ground wire.                  Never have seen any further info, regarding how to identify other iterations, so- can’t swear to anything.     Input resistance measures 7.8 Ohms (plus probes/leads).