Hello, after rigging up those cables and starting recording i have noticed that channel 1 and 4 on this deck is slightly more hissy than channel 2 and 3 with channel 1 being the most hissy. I am aware this deck was biased for the tape i used and calibrated but since the controls to adjust this are right on the deck i would like some advice on what i would have to bias or calibrate to adjust and lower the hiss on this decks first channel and even out the noise across all 4 channels?