February 10, 2010

Donald North Audio Sonett

I just picked up a DNA Sonett headphone amplifier. I first heard it at a headphone trade show last year and was extremely impressed. I currently have it hooked up at my workstation and being fed by a Neko Audio D100 Mk2 DAC. The higher output voltage of the Mk2 is necessary because the Sonett's gain is limited; I usually have it set to a volume level around 4 out of 10. I'm using AKG K 702 headphones.

The Sonett is a class A triode design and the first piece of tube gear I've owned. The nicest thing about it is the lack of obvious and subtle smearing so music is quick, accurate, and I can hear more of what I'm supposed to. This is partially due to the zero-feedback design. It also has absolutely no noise floor. The D100 has no audible noise floor either, and so the music is the only thing you hear.

Another interesting feature of the Sonett is the ability to switch its output impedance from 28 ohms to 120 ohms which matches the IEC 61938 specification. The HeadWize Headphone FAQ mentions this, and in particular says well designed headphones should have a fairly flat impedance curve. In that case, the higher 120 ohm output impedance shouldn't result in a difference in the frequency response. The AKG K 702 sounds pretty much the same with either output impedance setting, which implies its impedance curve is basically flat and thus "well designed" according to that FAQ.

Posted by josuah at February 10, 2010 4:32 AM UTC+00:00