Nice headphones prep. The glossy version of Max's? I like both.
BTW, just got the TH900 today. Good headphones, but not as good as the HD800s (or HE6s). Nothing surprising. More suited for low-volume listening perhaps.
Couple things. Read my post again please. I said if your power is bad, then conditioning and especially regeneration are beneficial. Otherwise, it's a waste of money...or atleast very poor value for your money. Secondly, I've always found cheap power conditioners and especially surge protectors to harm SQ compared to directly plugging into a wall-socket. Once again, assuming you have decent power in the area to begin with.
I'd focus on the DAC and transport from what you've described. Digital tech is moving ahead at a furious pace. Next would be the amp, and then power issues.
From what you've posted, I don't think it warrants any power conditioning. Just sounds like some ground loop issues. That money would give you greater gains being invested in a source/amp.
I think it's source-related mainly. I've found power conditioning to provide little to no gains for an unreasonably high cost if your local area is new and power is clean to begin with. It's a different matter if you live in an old building or are running multiple appliances or major electronics in the same room. Source and amp is where I'd focus my energy. If you can hear cable differences, then your hearing's not the issue. If you're using a computer, the transport...
x2. They replaced one of my HE6s last year without delay or hassle. Excellent communication too. BTW, my opinion of these cans hasn't changed since last year. Still one of the best I've heard, and tied with the HD800 for favourites. It was the silver cabling that really pushed them to the Senn's level IMO. Tight, jackhammer-like bass and a more energetic, involving but less fatiguing sound.
All mods I tried that involved adding material reduced the openness of the sound. None of them were worth it for me, especially since component and cable upgrades yielded improvements without such drawbacks.
Up for sale (preferred) or trade is a mint condition Black PWD MK2, bought from an authorized dealer last month. Product has been registered and warranty is active for 3 years (from now). Comes with all original accessories (most of them unopened). The DAC has been burned-in for a solid 400 hours, which it really benefited from.
This is the most resolving, lush and forgiving DAC I've heard, but selling for needed funds.
Read about the DAC here (reviews):