I found the following statement in a review of the PBN Mini-Olympia:
The Mini-Olympia has a switch on its rear panel so that the input impedance can be set three different ways: 75 ohms for BNC connection, 3.3k ohms for balanced, and 100k ohms for RCA.
I believe that your BAT preamp only provides balanced outputs, so you are most likely connecting it to the balanced inputs of the PBN amp, and their 3.3K input impedance. I strongly suspect that 3.3K is too low an impedance to be driven properly by the BAT preamp, and that the resulting impedance incompatibility is the cause of the symptoms you described.
I suggest that you contact BAT and ask for their recommendation as to the best way of adapting the preamp’s outputs to RCA inputs. Using a simple adapter or adapter cable may or may not be suitable, depending especially on whether or not the particular adapter or adapter cable connects XLR pin 3 to ground (XLR pin 1); and in any case a suitably chosen Jensen transformer (costing approximately $300) is probably a better approach.
Good luck. Regards
-- Al
