Treble Grain? How to Eliminate?

I've had a DacMagic for about a year now, using it mostly with USB input. I recently began using it in a headphone system and am noticing that this dac exhibits a high amount of grain in the treble. It makes for some heavy listening fatigue. Is there anything I can do to improve this? What other dacs under $1000 have a notably smooth treble?

mhdt Paradisea or Constantine. Both are smooth as silk.
Have you tried it with another input? Some say the USB is inferior to RCA in a lot of DACs

Grainey treble huh?

As much as it 'may' stem from your DAC, other factors too might be contributing.

Without more to go on it's a tuff call as to who the culprit is.

I would suppose, as You've had this issue ongoing for some time, you've tried using different cabling, power ckts., filtration, or headphones, right? As well as the above note on a different interface apart from USB. Right?

I've found quite often, etched, hard, or grain in the highs to be the result of incoming power that hasn't been adequately addressed.

Good luck.
I've also always had a suspicion that treble issues can be related to noisy power. I've tried connecting the DacMagic wall wart both to the wall and to my PS Audio UPC-200, but the UPC-200 only makes a marginal difference. The headphones I use are Sennheiser HD650 with an Elekit TU882 tube amp. I've also had the Audio-gd Compass Dac/Headphone unit; the dac inside the Compass was considerably worse with treble than the DacMagic. Also, the power cable on the DacMagic unit seems very weak and unshielded, so this may be causing an issue also.

I have tried comparing the USB to the Coax, and could hear very little difference, if at all.

Also, I have considered an MHDT dac, but I wish I could audition one first before buying.
move the switch to the other side on the 200... it's underneath the box and hard to move as it's recessed.

Try another wall wart/power supply for the DAC.

Try another pc on the 200.

Past that the MHD DACs go rapidly here so if you don't like.. sell it.

Lavery Eng makes very musical sounding DACs and I think they still will allow a 30 day home demo... not sure if they've gotten around to USB & headphone though.

headroom also might be an option. I hear much good about those folks products.
Do you have ANY OTHER DAC's to compare with? From friends? See if you can observe this phenomenon with another DAC. I would agree about the MHDT...very reasonably priced for performance. ESPECIALLY if purchased used.
My guess: It's jitter on the USB input. The measurements in the recent Stereophile review of the DacMagic confirm this:

Their conclusion: "...its USB input is really of only utility quality and shouldn't be used for serious listening."

Jitter results in frequency modulation that can present itself as shrillness in the treble. I can tell you that, when I addressed jitter in my system (with a reclocker), my high frequency nasties improved dramatically.

Good luck!