Hello and thank you for your replies. I also have had a feeling that more gain somehow sounds better, however with my Theta Gen. V through Pass aleph P with 4bsst c balanced 2V input, I have a problem with too much gain (Theta has higher than usual output signal) and can only listen quite loud. Maybe a time for a change of Pass or/and Theta since the 4bsst c is so far the most satisfactory piece of audio gear I have come across for 12 years.
Regards. Marcin