Bel Canto Pre2 Preamp plays in mono.

Glad that worked.  The Bel Canto gear is usually bulletproof and awesome.

That was it!  I can't thank you enough.  The tech guy at Bel Canto was on a wild goose chase so I've let him know.  The back of the preamp is situated so that it's very difficult for me to see the inputs, that's my excuse and I'm sticking to it.

Maybe double-check your connections, as RCA's are paired vertically and XLR's are paired horizontally?

I've tried pressing Enter, holding it etc.  The only options I get are for configuring the inputs, Enable Disable, Name etc. The manual does reference setting Mono / Stereo using the Enter button, but the only in regard to the phono stage and this is a Pre2 and only the Pre2P has a phono stage.   I've emailed Bel Canto and am waiting for a response.

Thanks.  I've been trying that and will try again.  I couldn't find any mention of that in the manual I found on line, searching for mono in the manual text. 

The manual says: Press the ENTER button, then use the up/down arrows for mono or stereo.