DO I SELL OR DO I KEEP

WHEN I MOVED ABOUT A YEAR AGO, I WAS TOLD MY STEREO EQUIPMENT WAS OBSOLETE AND THAT I SHOULD PURCHASE A SONOS SYSTEM.  I DID AND WHEN IT WORKS, ITS WONDERFUL; WHEN IT DOESN'T, ITS AWFUL AND THIS HAPPENS WITH SOME FREQUENCY.

I OWN THE FOLLOWING EQUIPMENT AND WOULD LIKE TO KNOW IF IT IS GOOD EQUIPMENT AND WHAT ITS WORTH IF I WERE TO SELL IT:

1.  SONY 5 DISC AUTO DISC LOADING SYSTEM

2.  NAD/RDS STEREO TUNER C 420

3.  NAD STEREO INTEGRATED AMPLIFIER C 370

4.  MARANTZ AV SURROUND RECEIVER SR5300

I'M OBVIOUSLY NOT AN AUDIOPHILE AND APPRECIATE WHATEVER OPINIONS I CAN REVIEW.

THANK YOU.

KENNETH