Are You sure there is nothing near Your amp supplying noise, some sort of wireless communications device? Wireless speakers, WIFI... I had a media center bugging me, and it wasnt even wireless, still produced RF noise, I guess..
Edit: Oops, just realized You may not have read Doc's latest reply above mine before I add another one. Sorry.
« Last Edit: July 03, 2016, 08:56:52 AM by Strikkflypilot »
Home system:
Sources: Ibasso DX90, Google Chromecast Audio optical out
DAC: Schiit Gumby
Amp: Bottlehead Mainline
http://bottlehead.com/smf/index.php?topic=7463.0Phones: HD800S
Office:
Sources: Iphone/ Ipod
DAC: Dragonfly Red+Jtrbug
Amp: Crack/Speedball heavily modded
Phones: HD580,HD600 grilles