HM-602 IMPRESSIONS: (I'll post this in the review section soon)
At RMAF 2010 last weekend I picked up a demo HM602 which had been burned in by Fang, and I've put an additional 24 hours on it since Saturday night. Low volume channel balance with the HM 602 is good with sensitive IEM, whether in low or high gain, just like the HM 801 which has enough power for HD800 and yet works great with IEM (and has no gain switch). I have not unpacked my full size phones from RMAF yet, and all my listening was with my best custom IEMs. I typically do not listen to full size phones with a DAP anyway.
GEAR: I did most of my listening with my Westone ES5 custom IEM because they are my best IEM and they can be ruthlessly revealing - I don't miss a thing with them. My JH13Pro have very good detail too, but with a little bit of added low-bass boost, so I tried these IEM at the end as well to look at synergy with all the players involved.
I initially began by comparing the 602 with my 16Gb 5G Nano (headphone out). While they are both a 16Gb DAP, the 602 can be expanded through the SD card slot and the Nano is stuck at 16Gb. The Nano has the advantage of syncing with iTunes, but it can't play 24 bit music like the 602 nor can it function as a USB DAC. I later included the HM 801 which is an upgrade to the 602, and the iPhone 4 which is an upgrade to the 5G Nano. I've always felt the iPhone 3GS/4 were my best sounding iPods, just below my previous 5.5G iMod. But in previous comparisons I felt the 801 beat my iMod as a source, and the built-in amp was very close to my best portable amps. So for the most part I left my amps out of this comparison because my biggest goal was deciding which was the best DAP for portable use, without needing to carry around extra cables and amps. I did do a brief comparison using the Pico Slim because it's my most portable amp, best with my ES5, and closest in timbre and tone to the 801's headphone amp.
MUSIC: I started with a 24/96 FLAC of Jimmy Cobb Quartet "Jazz in the Key of Blue" and Carla Lother "100 Lovers" in 24/96 on the 602, but a 16/44.1 Apple Lossless conversion of the same albums on the Nano, created with MAX on the Mac. It seemed fair to listen to them with the best quality music that they can handle, to extract their best performance possible. I believe the 602 down-samples the 96Khz music to 48Khz, but it does display the music as 24 bit on the display. After my initial listening impressions, I went back and listened to a 320K MP3 rip of Bella Sonus "Enamoured". This can be a bright or sibilant recording that would be good to test the players with a compressed format to see how they handle it, and it also has some very deep bass notes that go as low as approximately 25Hz in the beginning of the first song.
TREBLE: What first came to mind in the comparison is that the 16Gb iPod Nano 5G is a little brighter sounding than the 602. Although neither one seems too bright or too dark to me, the Nano seems slightly crisper but not actually more detailed or speedy. Without the forward or slightly aggressive highs of the Nano, the 602 still has a nice sparkle and shimmer in the cymbals, while the 5G Nano has a slightly harsh bite with the trumpets (although not sibilant or sizzling).
At this point I tried the HM 801 with this same 24/96 music, and I felt that it had slightly more treble presence than the 602, making the 602 sound slightly rounded off or soft in the highs in comparison. The 801 offers the same smooth refined highs with slightly better treble presence. The 801 also offers slightly better transparency and clarity than the 602 which I still preferred over the 5G Nano.
While the treble is where the 602 and 801 differ the most it's not a huge difference, with both being more refined and natural than the 5G Nano which is slightly boosted in the highs (but not too bright and better than my previous 4G Nano). I switched to my iPhone 4 with this same music in 16/44, and I felt the iPhone 4 probably has a similar treble presence to the 5G Nano, but it's more refined sounding and closer to the 801 in that regard. Throughout my listening I never felt the need for more treble with the 602, but it seems to be maybe 1-2 dB below that of the 801 or iPhone 4. My 48 year old hearing starts to roll off at 12.5KHz and is fairly well down at 16Khz, and you'd think that I'd prefer something brighter sounding but I don't, and I suspect that my brain has accommodated for this loss over the years.
MIDRANGE: The 602's mids are also a little fuller, warmer, richer and more life-like than the mids of the 5G Nano, making the 5G Nano's mids seem slightly thinner and slightly distant in comparison. This makes the jazz guitar on the Nano sit a little further in the background than with the 602. But the Nano also renders trumpets and guitars with less body than the 602. Overall the soundstage of the 602 seems slightly more forward than the Nano, due to the mids being more natural and solid. But without having done this comparison I would have never thought to call the 602's mids forward and I'd say they are just right.
The micro-detail, air/ambience and space is still very good with the 602, so I don't lose any of the size of the venue due to a more forward sound and rolled off treble, because I can still hear all the room echos intact with good separation. The listener is moved slightly closer to the stage with the 602, and farther away with the 5G Nano. The iPhone 4 is not as distant nor as forward sounding, but it's the 602 sound-staging that sounds more correct to me, and it comes very close to the 801 in this area. The iPhone 4 is very close to the 602 and 801 in the mids, and it's better than the 5G Nano as well, but it's still not quite up to the level of the 602/801. With iPhone 4 the trumpets and pianos don't carry quite the same weight or presence that they do with the 602/801. Again, there is not a huge difference but it's noticeable between iPhone 4 and the 602/801.
BASS: I also think the 602's bass is slightly more present or full-bodied sounding than the 5G Nano. The 602/801 and iPhone 4 are similar in that regard and they give a little better foundation to instruments like drums or string bass, although the 5G Nano is not lacking in bass nor is the 602 bass heavy in comparison. Typically the bass is one of the things I think the 5G nano does better than its mids or highs. However, the Nano and 602 headphone out still do not go as deep as when I use an LOD with an amp like the Pico Slim. Here I found the 5G Nano and the 602 to both be slightly rolled off at 25Hz, and even more so at 20Hz when comparing them to 31Hz and 40Hz tones (Bink Audio Test CD). The 801 and iPhone 4 were both a little stronger at 20Hz and 25Hz than the Nano or 602, although still not as strong down there as the Slim. So while the 602 bass is slightly fuller with slightly better impact than the Nano, its extension or depth is about the same.
AMPLIFIED: In a brief comparison, adding the Pico Slim amp to any of these DAPs adds more bass extension, and slightly more channel separation, soundstage, air and space. The improvement over the iPod's headphone out was bigger than over the 602/801 headphone out. But with the JH13Pro + Slim the bass is boosted a little more than I like for medium to loud volume listening, and I preferred the DAP's headphone out unless listening at lower volumes. The ES5 sounded great with any of these players, but I have to admit that they were still a little better when using the Slim. Again, the 801's and 602's line-out (with jumbo cryo silver X mini-mini) served as a better source to feed the Pico Slim than the iPods with TWag LOD, but their sound was still very good on their own.
For un-amplified listening the 801 is my first choice by a small margin, but the 602 is not far behind. Even my old iMod as a source for the Slim didn't have the same sense of space or refinement as the 801, so the iMod is gone now. I suspect that as close as the 602 is to the 801 that it would be ahead of the iMod as a source as well. In this sense the 602 is a bargain compared to a $500 iMod + $300-500 for LOD and amp. The money saved could by a lot of 32Gb SD cards for more music, or a nice set of IEM. I did feel that the Gap between players narrows when using the 602's line-out to the Pico Slim, but I don't feel like I'm missing much at all with using the 602's built-in amp and keeping the package more portable. I would not give up my iPhone 4 for the 602, but the 602 can offer a better musical experience while saving the iPhone 4's battery for phone calls, web surfing, movies or games.
USB DAC: Unlike the iPhone 4, the 602 can be used as a USB DAC/amp to upgrade your computer's built-in sound. The USB DAC sounds better than the Macbook Pro's built-in output, but it's not as detailed and spacious as my upgraded iBasso D4 or DACport. In the end I feel that both the 602 and 801 sound better listening to music on the SD card than through USB (although the 801's coax input is quite good too). Maybe sometime in the future I will do a more in depth review of the 602 as a USB DAC only, but I don't see that as its primary purpose and I wont be using it that way.
PROS/CONS: As far as Pro's and Con's go, I see the biggest problem with the 602 being the lack of Apple Lossless file support. Most of my lossless music is stored as ALAC, and not FLAC, AIFF or WAV. I do have several 24/96 hi-res downloads that came as FLAC files, and they play great. In addition to that, I converted my favorite 25-30 albums from ALAC to FLAC for the 801/602. But I'm not willing to convert another 70Gb (approx 250 albums) from ALAC to FLAC and store it for possible use with the 602/801 later. Plus I have another 250 CDs to rip into iTunes and don't want to do both ALAC and FLAC. However, most of my ALAC music has a second copy stored as a 256-320K MP3 to fit more music into portables with limited memory, and the 602 sounds very good with these lower bit-rate files. So, I'm not locked out of listening to most of my music library, only from listening to most of my lossless music unless I'm willing to put in the time to convert everything once again.
A second con is the 602's size, as it is about as thick as three stacked 5G Nanos, and 1.5x wider - making my 5G Nano + Pico Slim a smaller package. On the other hand, while the 602 is thicker than my iPhone 4 + Pico Slim, it's not as long nor as wide. Still, it will never be as portable for front pants pocket carry as a thin un-amped iPod.
The SD card expansion is nice, because one can add more music without having to carry around a laptop to sync music onto the device. I have three 8Gb SD cards filled with music, which can expand the internal 16Gb with music that wouldn't fit otherwise. The line out using a normal 3.5 mm jack is another plus, because it can be connected to other amps, docks and car connection kits without needing a proprietary dock connector.
SUMMARY: The HM-601 is a respectable portable DAP which provides better performance than the iPods I've tried, and doubles as a USB DAC/amp to upgrade your computer's sound. It's not cheap, but still in the ball park price of an iPod + LOD + amp and offering as good or better performance for the price. Its slightly muted treble extension doesn't take away from the experience for me; but some may not like that aspect of the sound, especially with a rolled-off treble or dark sounding earphone. It has an inviting musical quality which draws me into the performance just a little better than an iPod + amp, although my iPhone + Pico Slim comes close. And it has better synergy with my JH13Pro than my Pico Slim.
