This post is just as an advice in case someone experiences similar problem as mine.
I got HD650 with stock cable and as stated in the topic subject, a while ago I’ve had an issue with my crack picking up radio station signal. It wasn’t loud sound and I could hear it only in between tracks or when really silent music was playing, but it was annoying enough for me to start looking for the culprit. Typically in situation like this the usual suspect is an input tube, so I tried to shield my 12AU7, then replaced it with another 12AU7 and even replaced it with 6SN7 using adapter, and all of that without any positive results. It was weird, because when I put my hand over 12AU7 tube or 6SN7 then the radio signal got louder, so I was almost positive this has to be an issue with the input tube picking up strong FRI signal. It wasn’t.
After a while I’ve noticed that when I move around with my headphones on, the signal weakens sometimes and then gets louder in the area where I usually seat when I listen to the music. That made me thinking that maybe my stock headphone cable causes the problem and it acts as an “antenna†when I move around. I was planning to replace the cable anyway, so I’ve ordered some well shielded Mogami Neglex 2534 and I build custom cable for my HD650s, and... BINGO! That was it. No more noises, radios, etc. just silence and music.
It’s also worth to mention that Mogami sounds way better to my ears than stock Sennheiser cable.
Hope someone can find this post useful.
Cheers,
Kris
