Audible Hum

I had the same problem with my ReQuests.What you're probably seeing is a common ground loop. This occurs because of of all the grounds (e.g., the grounding pin on the power cords) on your equipment and the interaction with the shielding on the interconnects (grounds also). The most common solution is to use a 'cheater plug' (the small three-prong to two-prong devices)on the power cord of one component in you system. Experiment to see which component/power cord is the culprit.I actually had to use two on my system and it is absolutely quiet. Someone on another chat request suggests starting with the amp; I've also seen others suggest doing the experiment to identify the offending component. Remember though, you will be lifting the ground (Safety) from that component. That said, it is a fairly common problem and a fairly simple fix.

P.S. Checkout the chat topic "AC grounding" on the same list as your post

I had the same problem with different components, but the fix was the same. I put a cheater plug on my preamp and my system has not had any hum problems since.

One thing I recently found helpful, is try unplugging the inputs to your preamp to see if it goes away. I had my TV connected into the aux input, TV's are a great culprits of hum because there antennas are grounded. This solved my hum problem, and it wasn't present with the previous preamp.