See pages 28 and 29 of the following paper for a description of how to feed a single-ended signal into a balanced input without major degradion of noise performance. My thanks to Shadorne for calling this paper to my attention.
http://www.jensen-transformers.com/an/generic%20seminar.pdf
Regards,
-- Al
http://www.jensen-transformers.com/an/generic%20seminar.pdf
Regards,
-- Al