Just purchased a used RV6A (nice) with a KX 155 TSO Nav-com unit. On running a radio check with the tower they were reading me 5. However my reception of them, though crystal clear and static free was very low volume and the same on three different head sets and after turning up all volume options on headsets and panel and playing with squelch and different frequencies. Seemed to suggest that the low volume reception issue is in the delivery from the unit to the headset or is something else going on? I wondered if there is an option to adjust for this within the unit itself or am I off to the Aviation electronics repairers to give them my money ? Any advice appreciated.