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REVIEW: HRT HeadStreamer Asynchronous USB DAC/Amp

post #1 of 29
Thread Starter 

 

HRT HeadStreamer Review
 
Introduction
 
The HeadStreamer by High Resolution Technologies (HRT) is a USB DAC/Amp combo device. It has one USB input and one 1/8" stereo output. The USB input accepts up to 24-bit 96 kHz audio. The device is powered from USB and has no external power adapter. It retails for $140.
 
The most striking feature of the device is its use of the asynchronous transfer mode over USB. The HeadStreamer is the most affordable USB DAC that includes asynchronous mode as far as I know. Asynchronous mode allows the DAC to decide when data should be sent over the USB connection using its own high-precision clock. This greatly improves the sound quality by removing many timing-related distortions in the audio signal.
 
Another interesting feature is when you adjust the volume in Windows, it controls an analog attenuator inside the HeadStreamer. It avoids digital attenuation which can cause a loss of resolution.
 
Packaging
 
The Headstreamer comes in a white cardboard box, wrapped in bubble wrap along with a white micro-USB cable. It comes in a protective black felt bag with a drawstring.
 
Build
 
The Headstreamer has a metal enclosure with plastic end pieces secured by screws. The PCB slides in and out of the enclosure. The case and the end pieces have a "rough" texture to them. The USB and headphone ports are attached directly to the PCB, so there is no possibility of loose wires inside the case. It has a manageable weight that's not too light, not too  heavy.
 
Pictures
 
IMG_2644.JPGIMG_2659.JPG
IMG_2646.JPG
 
Parts
 
Inside, we can see that HRT has decided to use the TI TAS1020B for USB transfer. Basically, it is a programmable controller that supports asynchronous data transfer over USB 1.1. 
 
There also seems to be a 6 MHz crystal oscillator on board. 
 
For the DAC, HRT has chosen the TI PCM1793, a fairly high-end DAC chip. 
 
Headphone output is handled by two Burr Brown OPA 2132 opamps.
 
Installation
 
Installing the Headstreamer was as simple as plugging it in to the USB port on my laptop running Windows 7 Home Premium. The device was immediately recognized as "Headstreamer" and the drivers were automatically installed.  It was also automatically set as the default audio device.
 
Setup
 
My preferred media player is StealthAudioPlayer 0.22, which uses WASAPI "Pro Audio" mode and can handle FLAC files. All files used for listening tests were FLAC encoded. I tested the Headstreamer using Phonak Audeo earbuds and modified Sennheiser HD580 headphones. 
 
The listening notes below are based on the HD580 because I could detect no significant differences between the Headstreamer and my laptop's headphone jack when using the Phonaks. However, there were significant differences when using the Sennheisers. For all tests I set the volume at 60 in Windows which automatically adjusts the analog attenuator in the HeadStreamer. I would say most people would not go above 70. However, even 100, while it would probably cause ear damage, is not as loud as it would be on other headphones with a lower impedance. The Sennheisers are 300 ohms.
 
Listening Notes
 
Ottmar Liebert - UnderWorld (from album "Up Close," 24-bit 96 kHz Binaural)
 
Wow. I actually forgot I was wearing headphones for this track. There is a guy slapping a pot to the right of me. I can also hear the breathing of the guitarist. There are two guitars on this track, they both appear on the soundstage as completely separate points of sound. The soundstage is wide, but it feels like I am in a small room. Every instrument is reproduced distinctly and with realistic texture - guitars, bass, drums. I would rate this a 7.5/10 on the scale of "how close to reality" the recording is.
 
Soundgarden - Black Hole Sun (from album "Superunknown," 16-bit 44.1 kHz)
 
Guitars are pretty crunchy on this track. The best part of this track for me is Chris Cornell's vocals. I can really sense the depth in his voice. The bass frequencies from the drums are very well-defined, but not very impactful. I think this has to do with the frequency response of the Sennheisers. Soundstaging is more deep that it is wide. I can detect several layers of instruments. Drums, then guitar, then vocals behind. Even in very congested parts of the track every instrument is distinguishable. The resolution and detail is very good - this is most evident with the cymbals. The vocals are never grating.
 
Smashing Pumpkins - Bullet with Butterfly Wings (from "Rotten Apples," 16-bit 44.1 kHz)
 
First thing I notice is Billy Corgan's voice seems a little artificially compressed. I never would have noticed this with a less revealing source. The guitars sound amazing on this track. The drums and bass are very deep yet crisp, and together create a ambience that involves you in the music. The vocals are always on the edge of being grating, but the HeadStreamer/Sennheiser combo is able to keep them just energetic and not over the edge to painful. This is my favorite song.
 
Mumford and Sons - The Cave (from "Sigh No More," 16-bit 44.1 kHz)
 
Guitar is clear and detailed with great realism. After the first few lines of the song the sound changes subtly - the guitar is pushed into the background. The vocal is clear and crisp, with great depth and texture. There are a lot of very congested passages which are handled perfectly by the HeadStreamer - 5 or more instruments playing at the same time and all of them are distinct with full detail intact. Not a big soundstage on this track.
 
Tinariwen - Le Chant Des Fauves (from "The Radio Tisdas Sessions," 16-bit 44.1 kHz)
 
This track really shows off the bass frequency capabilities of the HeadStreamer. Even with the bass roll-off of the Sennheisers, the drums in this track are deep, controlled, perfectly timed and powerful. Overall the drums are very pleasantly rendered. They are hand drums, and every strike is reproduced with exacting detail. Guitar is fine, but not very exciting. Vocals are okay, but the effects of amplification (on the recording side) can be be clearly heard. The resolution of the this setup leaves me wanting a more realistic recordings.
 
Alicia Keys - If I Ain't Got You (16-bit 44.1 kHz)
 
Piano is 6.5/10 in realism. Can hear the reverb in Alicia's voice. The layering of the piano/guitar/vocal/drums is very clear and distinct. The upper range of Alicia's voice is very nicely rendered, again without grating or sibilance, unlike my laptop's audio jack.
 
Conclusion
 
The HeadStreamer clearly reveals the flaws of recordings that are not perfect. At the same time, for well-recorded material like the Ottmar Liebert HD binaural track it can deliver a true virtual-reality experience. My listening session leaves me wanting to upgrade my headphones (DT-880 600 ohm) and find a dependable source for 24/96 quality recordings.
 
While in absolute terms there are definitely tweaks and upgrades (maybe LM4562 instead of OPA2132?) that can be done to turn this device into a true giant-killer, in comparison to other devices in its price range I really do not see an alternative with the same level of sophistication in design. As part of the "first generation" of affordable asynchronous USB audio devices, the HeadStreamer stands out as an affordable, great-sounding device that will probably stand the test of time.
 
The HeadStreamer also has the same USB interface and DAC as HRT's other product, the Music Streamer II. I suspect that people with high-impedance headphones can opt for the Music Streamer II and an external amplifier for more voltage swing, albeit at a higher cost than the all-in-one HeadStreamer.
 
Rating
 
Features 7/10
Packaging/Build Quality 6.5/10
Ease of Setup 10/10
Sound Quality 9/10
Value 8.5/10
post #2 of 29

Nice review :). One question. One (only as of now) review in Amazon mentions that treble is a bit hot. Do you also feel like that?


Edited by adreamer - 2/25/12 at 10:58am
post #3 of 29
Thread Starter 

On some tracks the upper-midrange is pretty strong, almost to the point of grating. This may be what the reviewer meant by the treble being hot. However, it is even more so on my laptop's audio jack than it is on the Headstreamer. I think this has to do with the recording quality and not the Headstreamer, because on some tracks this quality is absent.

post #4 of 29

Thank you for the review!! Do you think you (or anyone) could do/show me how to do the math to determine voltage swing and other vitals of the headstreamer and audinst hud-mx1 so I can determine which will better drive my AKG K702s. Thank you!

post #5 of 29
Thread Starter 

The pdf on HRT's website says the HeadStreamer can output 130 mW max power and 1.4 Volts rms. Dividing by .707 gives 1.98 V peak to peak output. 

 

According to HeadRoom, the K702 has 105 dB SPL/V and impedance < 100 ohms across the audio frequencies. That's all I really know.


Edited by m3_arun - 3/5/12 at 9:40pm
post #6 of 29

 

In response to m3_arun's comment on the "...peak to peak.." voltage swing, their math is incorrect.  1.4 Volts RMS is 3.959 Volt peak-to-peak an error of 2:1 which is considerable.

 

As for Rockofeller's question about math to determine the compatibility between any headphones and a HeadStreamer, I wrote a simple to use Excel worksheet that will allow you to quickly determine the characteristics of any pairing.  If you are interested in obtaining a copy of this tool, please email our Support department and request the headphone calculator.

 

Kevin Halverson

CTO

High Resolution Technologies, LLC

 

post #7 of 29

Hi Kevin,

Please maybe tell us the hardware specs for the Headstreamer as well as if it works on Linux?

post #8 of 29

Hello gontadu,

 

I am not certain that I understand your question of "...hardware specs..." but would offer that you can download a data sheet on this or any HRT product from the HRT website.  If there are questions not answered, please list them and we will be happy to respond.

 

As for Linux compatibility, as long as the OS is class compliant, then the HeadStreamer would be compatible as it does not require any drivers.  Most, if not all, modern operating systems would fall into the category of being class compliant.

 

Kevin Halverson

CTO

High Resolution Technologies, LLC

post #9 of 29

Thanks Kevin!

 

I got all the answers via our email discussion!
 

Quote:
Originally Posted by Kevin_Halverson View Post

Hello gontadu,

 

I am not certain that I understand your question of "...hardware specs..." but would offer that you can download a data sheet on this or any HRT product from the HRT website.  If there are questions not answered, please list them and we will be happy to respond.

 

As for Linux compatibility, as long as the OS is class compliant, then the HeadStreamer would be compatible as it does not require any drivers.  Most, if not all, modern operating systems would fall into the category of being class compliant.

 

Kevin Halverson

CTO

High Resolution Technologies, LLC



 

post #10 of 29

GREAT to see Kevin Halverson here!

He's a TOP-NOTCH engineer, and NO BS

 

It's one of the reasons I was proud to work for HRT - they're products are hot.

 

 

post #11 of 29

And I see you are from another top brand! ofcourse I wish i could afford centrance :D
 

Quote:
Originally Posted by mikemercer View Post

GREAT to see Kevin Halverson here!

He's a TOP-NOTCH engineer, and NO BS

 

It's one of the reasons I was proud to work for HRT - they're products are hot.

 

 



 

post #12 of 29

Is this better than the X-Fi Titanium HD soundcard?

post #13 of 29

Now that's interesting. The OS controls an analog volume control on the device itself, and it's class compliant? I'd like a screen shot of Alsamixer showing the controls of the Headstreamer... Does it works like a standard PC audio card, with a "master" volume control, besides the PCM one?

post #14 of 29

Thanks for the review and the comments here. The new HeadStreamer arrived on my desk a couple of days ago thanks to my birthday and my generous brother-in-law, a software engineer and fellow fetishist of elegant DAC headphone amps. This replaces my first-generation HRT MusicStreamer, now almost an antique.

 

I’m still evaluating but the first impression is that the HeadStreamer offers a big leap forward in realism, soundstage presentation, and detailed dynamic range. A really sweet hi-fi sound. And the built-in ability to adjust volume via the Mac OS X system sound output control (or, say, the iTunes volume control, or both) is a great improvement over the plain-vanilla line-out of the old MusicStreamer.

 

 

 

 

post #15 of 29
Quote:
Originally Posted by mindstarr View Post

Is this better than the X-Fi Titanium HD soundcard?

The stand alone music streamer 2 would be the preferred choice. That is, if you have a separate amp.
Cheers!
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