High Resolution Technologies dSP Review

The newest product from the long-standing High Resolution Technologies (HRT) is a small one, both in size and pricing. The dSP line consists of two products (estimated $69/each). i-dSP can handle an Apple Lighting connection while the regular dSP is intended for use with a computer (via USB) and Android devices. The i-dSP still requires the purchase of Apple’s Lighting to USB Camera adaptor to work properly, so add another $30 on to the price to get things going in that scenario.

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Normally when I review a portable DAC there is quite a handful of options to compare it against within a similar price range. The new HRT dSP breaks away from the rest of the pack in that it is probably the least expensive portable converter I’ve come across that also includes a headphone amplifier option. The closest competitor I had at my disposal was probably the AudioQuest Dragonfly v1.0, which retailed for just under a $100 for a hot second when the replacement v1.2 first came out. Even so, the most current Dragonfly version retails for around $150, which is a far cry away from the $69.99 projected cost for the dSP. Probably the biggest competition to this new ultra budget range is Schiit Audio’s new Fulla ($79, still $10 more). Now granted, it may be possible to pick up a USB “sound card” made overseas for $5, but for the intent of this review we can keep the competitive analysis focused on products intended for higher sound quality over mere utility.

The build of the dSP is light. The bright red outer shell of the unit is clearly made of plastic, capped with two grey bookends that feature a small headphone jack on one side and a micro-USB on the other. The entire production is just over 2 inches long, the package here is even smaller than a pack of old school Big Red gum. The weight feels nearly the same and in the hand is very slight, weighing in at a mere .2 ounces. It really feels like something that you could take with you on the go with no issue, more so than most of the heavier, higher priced aluminum competition. The early issue model I was given had a slight jiggle to the internals that was noticeable, but this could very well be due to the pre production distribution and not something that I would expect from a regular model. The dSP should ship with a short cable for full size USB connections.

Connecting the device was a standard plug-and-play experience and operated as normal without a driver for my MacBook Air. A quick spec rundown from the company website reveals a 24/96 kHz resolution max and a .5 ohm output impedance to the small headphone jack. A quick spot check with a pair of sensitive JH16 IEMs provided a fairly black background for amplification. An insignificant hiss could be detected at very loud levels, but nothing that would be noticeable at normal playback listening and no background noise was detectable with full size headphones.

Comparisons to products twice the price start to tread an unfair border, which is even more problematic given that it really doesn’t take much to double the cost in the already saturated audiophile market. So I thought it logical to start at free, and see what grows out from there. The headphone output from my computer is somewhat of a smeared mess when it comes to reproducing music. It is nearly lifeless and fuzzy in nature and serves fairly well as a baseline to gauge the bottom of unaltered sound quality available to the average consumer. With the dSP plugged in the first noticeable quality was volume. The relative volume was higher than the internal headphone jack on the Macbook Air even at the same volume setting. The dSP does not come with an external volume control, similar to AQ’s Dragonfly, but unlike the Schiit Fulla which features a small physical rotating knob. The digital volume adjustments worked well, no problems with either the iOS controls or even fine-tuning from dedicated software like Audrivana Plus. Those looking for a little more gain than your average computer jack will find it here.

Aside from a little extra volume push, the little red DAC-that-could was able to extract a tic more acoustic information from playback files. Eric Clapton’s Lay Down Sally provides a nice even sound with a wide variety of instruments laid out in proper order across the stereo field. Compared to our baseline here, the dSP was able to provide a slightly more in-focus image for guitar, keys and vocals. After the first phrase the backup singers kick in on both sides, separated equally from the Eric’s main vocals in the middle. This fun little touch to the mix allows you to sense the relative space for each vocal with greater ease. Through the dSP, it was slightly easier to make out each back singers individual’s voice in terms of focus, detail retrieval and overall dimensionality. Using both a DSD file and Tidal streaming service, the jumpy guitars from the track felt even more dynamic via the little guy than through the Macbook Air’s default amplification. In relation to the jack, the dSP’s treble was a little less unwieldy even offered up a slight improvement in terms articulation. But there were a few shortcomings that kept the budget device from being a runaway hit.

I was lucky enough to receive a review pair of the new Layla universal in-ears from Jerry Harvey Audio just days before I started critical listening. The new flagship (which is sold by DAP manufacturer Astell & Kern) is one of the most revealing IEMs I have heard to date. Amplification duties can sound very different as you make the leap over from a full-size driver to the balanced armature technology that handles reproduction duties for most in-ears. A great amp for IEMs does not always yield the same results for headphones and vice versa. In terms of playback through the uber transparent Laylas, the dSP felt a little rough around the edges in the treble region at times, something that wasn’t apparent from other sources. These abnormalities weren’t quite as present though a pair of Audeze LCD-3s, but still left me with a feeling of detail over grace on many tracks. While initially the dSP’s mid section felt quite tidy and immediate, sometimes that same immediacy felt a little to forward around the human voice. If vocals are your thing, than this subtly may not even peak your radar, but in my never-ending quest for balance, I found myself reverting back to pink noise tests to confirm that things weren’t being overcooked. The results were actually very reassuring; I couldn’t pick up any major spikes in frequency along the entire spectrum when compared to my reference rig. Still, the sum of a rig is made up of much more than just frequency response, and perhaps the dSP reflects that. All in all the new HRT effort does bring the music a few steps closer which is most welcome, but it often made me wonder if it was possible to squeeze out a few more, if only baby ones.

$69 will hardly net you a decent portable player, and occasionally it seemed that through the dusty cellar of my memory, I had heard cellphones that produced decent sound (my old Galaxy S3 wasn’t half bad all by itself). A small step up to the AQ Dragonfly (original version on hand) will claim more gains for more money, the rule of diminishing returns almost seems less diluted on the more affordable side of audio in which these products call home. While an improvement over bare bones amplification, the lack of natural delivery from the dSP often made me long for my reference rig at times. Smooth, natural playback tied hand in hand with a high-end resolution makes for a very enjoyable listening session. Still, the gains over standard issue computer audio stand firm. More detail and more dimensionality push sonic rewards farther into view from the muddy, thin canvas of noisy computer vessels. Raw volume enhancements will undoubtedly complement less sensitive cans, and the portably factor is flushed out here at its maximum. Depending on your needs the <$100 wonder could still find its way into the appropriate rig. The “appropriate” window is unfortunately hamstrung by all of the tasty competition that floats just above the dSP’s price point in the $150+(and even the $300+) range. The small adjustment to your computer could come in handy for a quick improvement, but the serious audiophile perusing the market is probably already familiar with the alluring digital products upstream. The overall design effort against this market is very complementary, if not a necessary move for pricing in the grand scheme of things. What audiophile fare can be produced for the masses at a digestible cost? A leap up in quality at the cost of dinner and drinks is a good first effort, but can we squeeze a few more droplets of value out of the equation? The dSP gets the conversation moving the right direction and reminds us that it is still an exciting time to be involved in computer audio.

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Product Information:

• Product - High Resolution Technologies dSP
  
• Price - $69
  
• Product Page - Link
  

Associated Equipment:

• Source: MacBook Air
  
• DAC: AudioQuest Dragonfly (original version)
  
• Headphones: Audeze LCD-3, Audeze LCD-XC, Sennheiser HD650, Sennheiser Momentum, JHAudio JH16
  
• Amplifier: The Calyx Integrated
  
• Loudspeakers: Zu Soul MkII
  
• Playback Software: Audirvana Plus
  
• Cables: AudioQuest Victoria, Zu Mission RCA Mk.II-B
  

About The Author

Brian Hunter

I’m a recovering musician turned audio reviewer. I currently manage and write reviews for Audio-Head.com and freelance with several other publications. I love tech and the tools of music, especially the ones involved in reproduction. After I finished my undergrad degree in business I went to the local community college and got one in photography, which was way more fun. I like it when people have unbridled enthusiasm for something and I have the utmost respect for individuals who try to create, even more for those who are good at it.