Pros: PRaT, accurate, unforgiving, natural, neutral, great internal DAC, digital attenuator.
Cons: Unforgiving, neutral, DAC section occasionally malfunctions, digital attenuator, gain and reset switches.
This amp was my first audiophile amplifier purchase, bought second-hand off Midnightwalker. I wanted a neutral-sounding amp with an integrated DAC for convenience which would allow me to use it both as a desktop amp/dac and as part of a portable rig. I used this with the MacBook Air using the integrated DAC at a desktop and am currently using it with the Aedle VK-1 and M-Audio Q40, paired with the DX50 and a ZY HiFi audio cable while on the go, having previously paired it with the HD25 ALU and the NAD HP50. I have also tried driving the HD650 with these and comparing with the C&C BH2 and the DX50 in-built amp.
First impressions when I opened up the box were that the build of the amp was outstanding. It is made using a kind of raw metal (I forgot exactly what) entirely different from the usual anodized coating which gives it a unique flavour. The face-plates are made using a thicker layer of metal and the writing, although having heard rumors that they rub off, are still entirely visible even after 4 months of frequent usage. It also feels solid and has a nice heft that makes me feel confident in the amp's build quality, and I have not been disappointed.
The digital attenuator is another unique feature that I find very convenient. Pressing it turns the amp on and off while moving it to either side changes the volume, while also changing the colour of the LED (oooooooo flashy). The volume the amp was previously set to is remembered the next time the amp is again turned on which I as a lazy person find extremely convenient. However, I am aware other people find this way of changing the volume imprecise as the volume steps may be too large for some people.
Using the HD25 ALU, I felt that the amp is very true to the source. It makes good files sound amazingly pure and accurate while making bad files bite into your ears with an ice-cold chill. This also means that it is very neutral and unforgiving. It is almost like a wire with gain in that the amp will barely change the sound produced. Each headphone connected to the Glacier has its own unique sound. The HD-25 ALU is lively and with plenty of PRaT, the HP50 is natural with its famous roomfeel effect audible in full effect, the VK-1 is dark, impactful and smooth while the Q40 is bass-emphasized with neutral mids and highs. A little PRaT is injected into the music, giving it a sort of liveliness that is reminiscent of the HD25/grado effect. I find this makes the VK-1 sound amazing with vocals and instrumental tracks and the Q40 with more electronic-oriented tracks.
However, the neutrality and unforgiving nature of the amp can be a bad thing too, as when paired with the HD25 ALU any flaws in the recording are immediately made apparent. It may perhaps be a slightly too analytical combination to some people. The Aedle VK-1, being a can with very respectable technicalities, suffers in the same way in that flaws in recordings are audible in all their glory. In the same way, when paired with the HP50, I found the bass quantity to be lacking, almost like the AKG K550, although the quality was still outstanding.
When connecting the Macbook Air, due to the UAC-1 standard, using the inbuild DAC was completely painless. It is practically plug-in and play and has great synergy with the amp section. However, the DAC very occasionally malfunctions but TTVJ has implemented a handy reset switch in the case this happens which resets the microprocessor, solving all problems. However as with the gain switch, a toothpick or other sharp tool is required to press this switch
Overall, I am very satisfied with this amp and I do not regret this purchase at all. However, there are some small nitpicks with the DAC section and the usability of the gain and reset switches that do not hinder overall usability.
Paired with the VK-1
Paired with the HP50.
Paired with the MacBook Air using the internal DAC.