[manbear]

 
Review: HRT Music Streamer II and JDS Labs Cmoy 18V

This is a review of the HRT Music Streamer II and JDS Labs Cmoy 18V taken together as a whole. I have not used either component independently of the other, so my judgments only apply to the combination of the two. While this may not be helpful to those who are only interested in one of these products by itself, those who are considering pairing an Music Streamer with a Cmoy should find it informative.

My setup consists of the following: Lenovo Thinkpad running Windows 7 → 16/44.1 and 24/96 FLAC → Foobar2000 running the ASIO4ALL driver → generic USB cable → HRT MSII → Monster RCA to mini cable –> JDS Labs Cmoy 18V → Beyerdynamic DT990 250ohm.

Before, I listened to the DT990s straight out of my laptop's headphone jack, so that is my reference. I hope that my impressions can be useful for others making the jump from a stock headphone jack to a dedicated amp/dac combination. I think that people notice audio quality relatively, as a change in relation to what they were previously used to. Thus, my comments should be relevant for those who are wondering what kind of difference an amp/dac really makes.
 
Surprisingly, I noticed a considerable difference between using ASIO4ALL and the default drivers in Foobar – ASIO4ALL noticeably tightened up the sound. I didn't notice much difference between the two using the stock headphone jack.
 
I noticed the following improvements to the sound with the addition of the amp and dac:
 
- Increased detail, especially in the bass. Sounds have more texture and better microdynamics, they become more tactile and palpable. The sound is just tighter and cleaner. .
- Increased low-level resolution – ambient effects are much more noticeable.
- At first I thought that the treble was more emphasized, but after a few weeks of listening it's settled down. The DT990s are a little bright to begin with, but now the treble is smoother and more detailed, more resolved and less grainy.
- Better separation of sounds – soundstage isn't necessarily bigger, but it is clearer and more focused. Individual instruments stand out separately and more clearly.
- Way more headroom – I frequently had my laptop's internal volume up all the way and wanted even more oomph, whereas 11 o'clock on the Cmoy is about as loud as I can stand.
- Background is much more silent – with no music playing, I have to turn the volume knob to around 3 or 4 o'clock to hear any hiss at all, compared to around 11 o'clock being the loudest I can stand for listening. There is no noticeable hiss at all with the volume at 11 o'clock and no music playing.

If the jump from my old Sony MDR V6 to the Beyer DT990, using the same laptop headphone jack, is a 10, then the jump from DT990s through the stock headphone jack to the DT990s through the amp and dac is around a 5. There is a noticeable improvement but not it's not jawdropping. Not that one would necessarily be right to expect the same level of improvement, but I wanted to put it this way in order to give some idea of how much improvement to really expect.

However, putting it this way is a little deceptive. When I go back to the stock headphone jack, the drop in sound quality is more readily apparent than the increase was the other way around – everything sounds loose and muddy, like low bitrate mp3. In some ways, it's easier to get a sense of how these devices improve the sound in reverse, by listening without them. Putting the amp and dac back in the chain, the improvements can be easy to overlook because the music just sounds more natural. I suppose this is the ultimate goal of audio equipment, to get out the way and let the music sound like itself.