Aux input sound quality
Also the Aux, depending on the Audio 20 unit, has a -6 to -12 dB engineering fault in its input. Try and see if you have the Aux BOOST activated. If not, then PHP Audio sells the "Sound Shocker", an impedance matching transformer that can restore the attenuated signal.
http://phpaudio.jigsy.com/passive-preamp
Make sure you put the Aux volume on BOOST. And the iPod volume on "8" with the EQ on "POP" for best sound quality. If this is still too low (also for an MP3 player which should never be used on its max volume) get a PHP Sound Shocker here:
http://phpaudio.jigsy.com/passive-preamp







