AMB Labs have been known for making fine audio products, and the Gamma2 is no exception. I find the sound out of the Gamma2 to be very enjoyable. It manages to present a very balanced presentation. Its sound can be considered warm, but not too warm and still enough sparkle to please people who likes detail. There is enough forwardness in the upper midrange to present some intimacy, but it’s never too agressive in its overall presentation. Like other AMB Labs products, the Gamma2 links technicalities with musicality very well.
When I compared the Gamma2 to the Audinst HUD-MX1, I found the two to have quite a similar sound, and that most people won’t even notice the difference outside of long term A-B listening. I do find the Gamma2 to possess a wider soundstage and a little more detail than what’s found in the Audinst HUD-MX1. The upper midrange on the Gamma2 is also more forward, which adds a nice sparkle and intimacy to the music. In contrast, the HUD-MX1 is a little more laid back in the sound presentation. What I did like about the HUD-MX1 is that soundstage image is more coherent, and that there is more connection between the left and the right soundstage.
I also compared the Gamma2 to the Dr. DAC Prime. The Dr. DAC Prime is more detailed, but at the same time it does have a more recessed midrange (although not as bad as the Ibasso D10). For classical music, a little recessed midrange it’s not an issue, and the added detail on the Dr. DAC Prime is definitely welcome. And also, on some headphones that have enough body in the midrange like the Grado HF2, the HP1000, the HD600, you probably won’t notice the recessed midrange as much. But other than that, for the majority of music that has vocals, I would probably recommend the Gamma2 over the Dr. DAC Prime.
So, the Gamma2 has found a nice spot in between the $179 Audinst HUD-MX1, and the $499 Dr. DAC Prime. Although if I think about it, for almost $300 in the current configuration (with internal clock and ASRC chip installed, and the Sigma25 power supply), there seems to be little added value in the DIY section, seeing that the Audinst HUD-MX1 is able to sound very close to it, and even throw a headphone amplifier in one package. I think the law of economics is at work here, and that having the advantage of high volume production, the Korean manufacturer is able to still maintain competitive price over the DIY product, where you don’t get discount pricing for the parts, and likely to pay multiple shipping fees to get all the necessary parts from different sources.
This particular Gamma2 build comes with the Wolfson WM8741 which adds a built in digital filters that gives you an option of how you want the frequency response to fall off (likewise the WM8742 also gives that capability):
– Filter C has the most extension, but also comes with the sharpest cutoff.
– Filter B trades some top end extension for a more gradual cutoff.
– Filter A is the compromise between C and B.
I did play around with the filters, and found C to have more sparkle, yet rougher on the edges and more fatiguing, where filter B is softer and more pleasant to the ears. Keep in mind that we’re talking about frequencies way above the audible range. Filter C will go all the way above 40Khz, and filter A and B above 30KHz. How these frequency cutoffs above the audible range affect what we’re hearing in the music? I’m probably not qualified enough to explain.
What about USB input versus the S/PDIF inputs? I ran a cable straight from the MacPro’s optical out, and I compared it to the USB input, and I found no audible difference. I really can’t compare the USB to the coaxial, as the MacPro doesn’t have a coaxial output.