Headphone Amps

A/B Comparison #12

• Sigma 22 power supply.
• Three-channel "Active Ground" topology.
• See http://www.amb.org/audio/beta22/

LCD-2

Interesting differences. The NFB-10ES amp sounded a little brighter on the very top end, and maybe the treble of the Beta 22 sounded a little smoother too.  Bass was great from both amps- the Beta 22 was somewhat more controlled, the NFB-10ES a bit less controlled which gave the NFB-10ES a sound that had a little more bass "action" in it. A little "fuller" bass, not woolly but almost littlemore bass, while the Beta 22 was tighter sounding, more emphasis on bass texture.  Even so, the NFB-10ES bass was not sloppy- it had good "punch'- but the Beta 22 was just more fully in control.

HD-800

The NFB-10ES exhibited the same slightly emphasized high treble on the Sennheisers, but somehow it was not quite as noticeable as with the LCD-2.  It was almost as if the Sennheisers bright sound gave an impression of a little extra treble in the ~6 kHz area no matter what amp they are paired with, and this masked any extra treble added above 10 kHz by the NFB-10ES. I couldn't notice any difference in the bass, both amps sounded great on the low end.  I think the extra bass resolution / detail that the LCD-2's offer showed the differences in bass between the two amps while the HD-800s just didn't allow me to discern this. 

MY CONCLUSIONS

It's possible that part of the slightly "brighter sound" of the NFB-10ES is inherent in it's amplifier circuit, not just the DAC. I preferred the Beta 22 sound by a small margin on the LCD-2's, on the HD-800's it was much closer, really pretty much of a toss-up.

This test is a little different- I cannot use the Cambridge DAC Magic as a source because the Audio-Gd NFB-10ES does not have analog audio inputs.  So, the Audio-Gd NFB-10ES is fed with SPDIF (RCA) and it's own ESS DAC is used; it's DAC line level analogs outputs (RCA) feed the Beta 22.  To switch from A  to B, one switches the headphone from the single-ended amp output of the Audio-Gd NFB-10ES to the output of the Beta 22, and simultaneously switches the Audio-Gd NFB-10ES to "Preamp" which sends the analog signal of the NFB-10ES DAC output to the input of the Beta 22.