Hi, I used to own a PD170. Its audio should not be that bad unless you did some of the followings;
1) Forgot to turn on the Phatom power?
2) Left it on Mic AGC?
3) Connect only chnl 1 but left the settings for separate chnls?
4) All of the above?
If in doubt can always refer back to their manual which is quite clear with all the settings. all the best!