Recommendation for USB audio interface, Low output impedance, low absolute noise level Options

[googlebot]

I have a pair of excellent IEMs with 119 dB SPL/mW sensitivity, that aren't too easy to drive on conventional higher-impedance headphone outputs (2-way balanced armature, <27 ohms). I'm looking for a desktop USB interface with manual volume control, a headphone jack with low output impedance (~0 ohms), and a low absolute noise floor (due to the low sensitivity). Many manufacturers post their SNR figures, which do not help me decide, whether the latter requirement is really fulfilled. For example, with the IEMs plugged into an onboard Realtek ALC261 output, which has got a SNR close to 100dB, I can hear the SSD working.

I had a look at the E-MU 020x devices, which seem to be great, but their 22 ohm headphone output jack looks like a constraint for the intended usage.

Could you recommend anything else?

*** Edit: I just noticed: Sorry, wrong forum. Please move to 'Audio Hardware' if you find the time.

This post has been edited by googlebot: Mar 31 2012, 13:14

[googlebot]

After extensively testing the Yulong U100 I can report that I'm more than happy with it. Sound and both relative and absolute SNR are exceptional.

IEMs provide an opportunity to drive 16 bit to its limits without damaging your ears, since a good portion of the baseline noise, that you have to live with in an usual listening environment, is kept out and you're feeding sound directly into your ear canal. Even with the maximum, pain-free listening level, recordings (and sometimes their recorded noise) seem to ascend from a floor of absolute silence - or the sound of my blood circulation (but my brain usually takes care of filtering out the latter).

The Westone UM2 has got an impedance curve like a rollercoaster. The U100 doesn't seem care, great bass, no perceivable roll-off whatsoever.