I was asked to review the HLLY DMK-IV DAC/Headphone Amp by the manufacturer, who sent me a review loan sample unit from China. The unit seemed to be well packed...but… one of the RCA jacks had broken loose. There was nothing loose inside though, and the unit worked flawlessly in spite of the broken jack. The unit was labeled 220V, even though it was 115V – which I do not like – it should be properly labeled. That said, the product appears well made, and is handsome: This review is a PRODUCT review – not a company review. HLLY has been selling a tube amp which looks almost exactly like a Little Dot amp. Either they OEM it from Little Dot, which is fine, or they copied it, which is very much NOT fine. But the DMK-IV looks like nothing else I know of, and I have no idea what HLLY’s general business practices are. This review was written completely independently of such considerations, and I will request that those who comment on the review refrain from degenerating the thread into such a discussion. That can be discussed elsewhere. I broke in the DMK-IV for 100 hours before use. As a DAC/Headphone amp combo, I tested it with the Denon D7000, Beyerdynamic DT880 and T1, and the HifiMan HE-5. I used the DAC by itself from the analog outputs (fixed), but not as a pre-amp, although the DMK-IV does have pre-amp outputs (which I did not test). I compared the DMK-IV extensively to the Music Hall DAC 25.2, which makes for a great comparison since it has a very similar feature set, and is only marginally more expensive. While the DMK-IV has a preamp outs that the Music Hall does not, the Music Hall has balanced outs which the HLLY does not. Both have built-in headphone amps. The DMK-IV purports to use the Crystal Semiconductor CS4396, which is a 24-bit DAC. This must be the same chip that one of the many other DACs I have tested, since Windows did not install new drivers, it used one that was already there. The specs on this chip are very impressive – 100db s/n, 120db dynamic range, low clock jitter, etc. I used the DMK-IV both from USB and from Toslink. It sounded a little better from the Toslink input (which is what I normally find). It also has a COAX input I did not test. The DMK-IV comes with a little remote, which is nice and worked well. The control knob is a little cheap feeling, but works. The rear RCA jacks are chassis mounted and appear to be high-quality. Overall, the quality and workmanship seems very fitting of the price – nothing exotic, but very nice. I used the HLLY as a DAC, connecting it via optical to my Denon transport, and then connecting the DMK-IV’s DAC Out RCA connectors to the Audio-GC Phoenix headphone amp. In this application, the HLLY sounded truly excellent. It was very neutral, with excellent extension at the frequency extremes. The sound was well detailed, but not at all bright. Midrange was open, and while definitely not lush, it was not at all thin. “Neutral” really comes to mind over and over again. The DMK-IV did not call attention to itself as a DAC, but let the music flow in an un-colored, transparent way. The sound from the acoustic “We Lost the Skyline” CD from Porcupine tree was really outstanding – nuanced and clean, and the soundstage was great. I was very impressed with the quality of the sound that the DAC was capable of producing. The sound from the headphone out, on the other hand, was decent, but un-inspiring . The sound was a little soft at both frequency extremes. It lacked deep bass weight, and the bass was a little light overall, although punch in the mid-bass was good. The fact that even the Denon D7000 seemed to lack a little bass weight versus what they produce normally was a little disappointing. And the bass was even a little mushy with the Beyer DT880 – which is also not normal. There is a grain that overlays the sound from the HP out that I wasn’t able to listen past very easily – and as a result it lacks a little transparency. This is most noticeable in the treble, where the sound lacks purity. The treble wasn’t aggressive – but it wasn’t really clean, either. Compared to the Music Hall 25.2, this was quite noticeable, even though the 25.2 does not have the greatest headphone amp in the world either. Still, the only slightly more expensive Music Hall was definitely better sounding from the built in HP out. The mids were also subject to a slight lack of transparency, and were a bit forward. The combination of the forward mids and soft treble pushed the soundstage forward. The mids weren’t thin – they were reasonably smooth – but they again lacked a little transparency. Soundstage depth was only fair, and width was also only fair. Image specificity was also only fair. So my recommendation of the DMK-IV has to be somewhat lukewarm. It offers competitive sound as a DAC to the Music Hall 25.2. The headphone out of DMK-IV, IMO, doesn’t offer competitive sound –it just doesn’t have a very musically engaging sound. While it’s not very expensive overall, at $370 shipped, and is quite full featured, I’m not sure that it’s as good a value as it should be when you factor in that the headphone out isn’t that good. It simply didn’t offer the level of sound quality that is now available from products in roughly the same price range, and was definitely a step below the Music Hall 25.2, which, while more expensive at $500 street price, is well worth the extra money, IMO. I don’t want to seem too critical – the DMK-IV sounds great as a DAC – really very impressive sound. But as a headphone amp it doesn’t sound all that impressive – in fact, in that regard I found it disappointing. And even as a DAC, via USB it wasn’t even quite as good sounding via USB as the KingRex UD-01 w/PSU, which I still have on hand as a reference, which is similarly priced (although has less features). It DOES offer a lot of features for the money, though, and I suppose it’s possible that with certain headphones, it might synergize better. But for me, I did not find the DMK-IV to be a product I can recommend with any enthusiasm for headphone listening – you need to pair the DMK-IV ‘s excellent DAC section with a better, external headphone amp to hear the quality the DAC is capable of.