[Navyblue]

I used an Electroswitch 3 pole rotary switch as source selector in an amp I built. The ground is switched along with the L and R channel.
 
Let's say I have source A connected to position 1, and I have noting connected at position 2. When the switch is at position 2, at very high volume level (near max level), I could hear the music that is playing at source A along with some whirring noise. The volume is soft, but enough to hear what is being played at source A with AKG K501 (a pretty inefficient headphone). I imagine with other more sensitive headphones it will be much much worse.
 
I have a lot of cable connected and jammed together at the switch, is this the cause? The cables are all shielded though. Or is it the rotary switch?
 
Thanks in advance.

 

[cyberspyder]

Switch. Although alot of rotaries have this problem.

 

[Navyblue]

Thanks.