After 1 day of listening, about 12 hours of use, varying circumstances. I have used my Monoprice M560 and Beyerdynamic Custom Studio headphones and my RHA S500 in-ear headphones. I have had the D30 connected to my SP3 via USB and my PS4 via optical. I even plugged in my little Blackweb Bolt bluetooth speaker via aux cable. My listening style is what some call "strange", I listen to mostly anything but my regular genres are new age, classical, classic rock, country and jazz. I also watch a lot of videos and shows off the web. So I have placed this setup thru some paces in the first day. I use several different music sources, I stream with Tidal premium, Groove Music, Youtube and have 200+ cs's that have been ripped to FLAC on my SP3 and OneDrive.
I do not claim to be an expert when it comes to sound and I am not musically gifted at all. But I do love music and making my ears happy. This is my first step into a desktop setup of any kind. All my previous expierance with an amp has been portable devices. So I have limited options to compare with it.
Let's get on with my thoughts.
Build quality is awesome. I like the size, fits great on my desk. Seems to be solid and durable. The switches and volume knob have nice feel to them and are responsive. Doesn't look cheap or feel cheap.
I didn't have any issue connecting the D30 with my Surface Pro 3 and Windows 10. As soon as I connected the USB dongle Win10 found it and loaded the driver. The only time I had an issue was when I had to restart my SP3 after a Windows update and a simple remove USB from port and reinsert, rectified the issue.
Sound is what I came to expect after reading reviews. I think the D30 does a very good job of cleaning up the sound and not coloring it in any way. The sound seems to be a little on the brighter side but not in a harsh way. The bass has nice quality and reaches deep if needed, very fast and responsive. The mids seem to be slightly recessed but not overpowered by the bass or treble. In some rock, guitar distortion can be a little troublesome, especially if it is on the higher end of things. I haven't heard any distortion or muddiness. I really like the sound of the D30, fits my style of laid back, relaxed , comfortable music listening. I do not like music to be forward, loud, in my face. I like to be able to sit and drink my coffee and read internet articles or creating a lesson plan while relaxing with my music pumping in comfortably from my M560's.
The A30 is an interesting amp that I am trying to get used to. I have never had an amp that had both a lo and hi power switch and a 9db and 18db gain switch. I am not sure of the ins and outs of all that. I am mostly using it without gain and low power. I do use the 6.35mm jack with both my M560 and Custom Studio's. I find that if I up the gain that neither of my headphones respond greatly, it seems to open the soundstage up a little but also makes them bright; especially the M560. I don't mind the 9db but the 18db is too much. If I move over to the 3.5mm jack the 18db is slightly less bright but still too much for my taste. I do think that the sound from the 6.35mm is preferable for me without gain. If someone can explain that for me in layman terms, I would love to learn more. As for the sound from the amp, it is pleasing to my ears; no coloring or extra boosting. I really like how it pushes my M560, the Custom Studios are a little less exciting but that is to be expected from them. The Custom Studios also take more on the volume dial and do respond better to the gain switches. I have spent, about 1.5 hours with it connected to my PS4 and it was amazing. A lot better than hooking up through the remote jack. The RHA S500 didn't sound good at all thru the A30; way too bright, only played a couple of songs on them. They will still remain my portable option with my LG V20. Hooking up the Bolt bluetooth speaker via aux cable was not bad. The A30 pushed it nicely, may have been a slight improvement in sound but not overly noticeable, bass was not as boomy, considering we are talking about a $40 speaker from Wal-Mart.
Overall, I am very happy with this purchase. I love the sound that is produced. I am trying to learn the differences with the lo/hi power and gain switches, a little help may help me further my love for my D30 and A30.