[Bsimmer3000]

Hey guys. Just signed up because it seems you lot know your stuff with computer audio.
 
I have a desktop PC i have added some Rokit5's too. I am getting some really strange issues. I first tried to run then from a phono to RCA cable. They worked great on my iphone but the PC had horrible ground loop type hum. I took PC apart and re routed and screwed everything back tight. It was still there and its def coming from the PSU side but no other speakers have ever done this on my system.
 
I then tried a power conditioner and no help. then a Behringer UCA202 which didn't help either. as soon as the USB even touched the PC case i got the ground issue. I tried cables with no ground pin also.
 
I also noticed i get noises when ever i open a program or switch windows and scroll also.
 
I then tried a OREI DA9 Digital to Analog Audio Converter - 192kHz/24bit Optical and Coaxial DAC which took away 99% of the issues but now i am having issues with a static noise every 30 seconds and a very slight power hum. i guess the power supply for the DAC could be causing this issue as it stops when i unplug that from the unit.
 
Getting to the point I'm ready to just get rid of these speakers. they sure are fussy on the equipment they like to be used with.
 
Do you guys have any tips on getting this to run correctly?

 

[PleasantSounds]

Looks like you have tried pretty much all the tricks.
The hum between DAC and speakers is also a ground loop - it's just subtler as the DAC's power supply is cleaner.
I suspect the speakers are either faulty or have some design issues, but everything is pointing in their direction. 
You can still try one more thing: google "rca isolation transformer" - this will break the ground loop, but I have no idea if it will be 100% neutral to the sound quality.

 

[Strangelove424]

What kind of PSU do you have and what are the specs of your system? Noises while opening programs points to a PSU issue, particularly since it happens while the computer is under load. A good PSU will supply clean, flat power under all kinds of loads conditions. Also, for the DAC, have you tried plugging it's power supply into a separate socket than the PC? It's usually suggested to plug them into the same socket to minimize ground loops but I found in my setup that I got less noise when they were on different sockets (and different circuits). 

 

[Bsimmer3000]

Thanks for the reply guys. I will check that isolation transformer out right now.

I have a 1000w BFG supply that was very high end at the time. I think I paid about $250-$300 for it so it's not a cheapo. I'm running a pretty basic setup with asus pq5 turbo, 8gb ram, 2.6ghz quad core over clocked to 3.2ghz, 3 hard drives, 1 GeForce gtx660, water cooling, 2 blu-ray drives a few fans and that's about it. Well within my PSU specs.

Tried different circuits and different circuits with conditioners also. Def seems to be the power adaptor to the DAC unit. I have some ferrite core clips on order and a different way to power the DAC which gives me some more options to power it.

 

[peepr]

I am having similar issue.  Just got a magni today and have issues with static/hum from fiio e7 as my dac.  Like you, when I even touch the usb to the back of the computer or any metal on it, I get static in my headphones.  Trying to figure this out as I don't want to spend more $$ on a dac w/ optical.

 

[peepr]

Ok i solved this. My powerline adapter, when plugged into the same wall as my magni would cause static even without having rca cables plugged in. I removed the adapter and use wireless on my desktop now.