None of our gear uses balanced-line inputs or outputs in stock form, at this point. There are ways to connect balanced to unbalanced gear, though they generally reduce or eliminate the potential benefit of balanced lines. The Jensen Transformers web site has several technical white papers on the subject, which are actually quite good.
The Foreplay is optimized for nominal unity gain operation. It has 10-12dB total gain, so with the control a bit above halfway the gain is unity and the output voltage equals the input voltage - this leaves plenty of extra gain for the rare occasions when you need it, with plenty of lower volume settings for late-night listening.
Consequently, you want an amp whose input sensitivity, combined with your speakers' sensitivity, gives normal listening levels with 2-v peak inputs. Very many amplifiers are much too sensitive, especially if you have sensitive speakers or purchase an amp with much more power than you will actually use.
I have a white paper on the Bottlehead Community page, discussing signals and noise in some detail. It might be of some help. I'm afraid the subject is a bit technical, but I'm glad to help when needed.
