Articles, Reviews and Measurements of Audio Products (As an Amazon Associate I earn from qualifying purchases)

This is a review and detailed measurements of the Matrix Audio Element i USB DAC and Ethernet/Wifi wireless streamer. It was kindly sent to me by the company and costs US $990.

The Element i embodies the beautiful design language of other (newer) Matrix Audio products:


The menus and settings are controlled using two buttons and rotary encoder. There is a headphone out but I did not get a chance to test it yet. Will do as a follow up.

The back panel shows the usual suspects:


Unlike other Matrix Audio products I have tested, the Element i uses an external switching adapter. It is about twice the size of a phone charger.

Both wired Ethernet and Wifi are there as is my favorite, Roon player streaming protocol. Roon however complains that the implementation is not certified. I had no trouble using it but I encourage Matrix Audio to get the certification.

For my testing I focused on...

This is a detailed look at temperature sensitivity of the ESS ES9038Pro DAC chip as used in SMSL USB DAC. In a separate thread it was shown that another unit had its performance improve with temperature/on time whereas my review sample performed the reversed. I purchased another M500 from Amazon Prime which means it was already in stock in US. It arrived today and I thought I create this separate thread on the performance of the two relative to temperature.

Taking out the PCB is a bit of a challenge but I managed to do so on both. Pulling the PCB out all the way disconnects ribbon cables form front panel which I have not figured out how to open yet! So I left the review sample (bottom) half out with cables still attached and the new retail version (top) fully removed:


Both PCBs look the same to me and both have the same version 1.2 indicated on them. The DAC has two boards but the top one is of interest to us since it has the...

This is a review and detailed measurements of the vintage (?) Yamaha RX-596 Receiver (stereo amplifier with tuner and video switcher). It was purchased by a member from local charity (Goodwill) for US $10 plus $18 shipping. No, that is not a typo. He did buy it for just $10. It was sold "AS-IS." Shipping was likely less since the branch of the charity is local to us. If the amp in it performs, it will be the bargain of the year.

RX-596 is not that heavy relative to its size and looks as modern as today's gear:

Please excused the bowed sides. I have not screwed the lid in as I plan to clean it more before giving it back to its owner. As shipped, there was an inch of dust everywhere. OK, it was just 1/8 of an inch but it is more dramatic to say an inch! More on this later. Here is the back panel:


Before testing, I exercised all the controls to get rid of some of the surface...

This is a tear down of the recently reviewed Schiit Magni Heresy Headphone Amplifier. This version of Magni is uses integrated circuits ("OpAmps") as opposed to discrete output stage which in my measurements, garnered it far lower distortion and won my strong recommendation.

The screws were a bit less tight than the Magni 3+ I disassembled:


The architecture here could not be simpler. AC input is rectified, filtered with good quality capacitors (Nichicon) and regulated to + and - 17 volts. Input signal is amplified by the OP1662 opamp/buffer.

A cluster of four OPA1688 headphone amplifier/opamps are used per channel. OPA1688 has exceptionally low distortion+noise...

This is a tear down of the Schiit Magni 3+ headphone amplifier which I just reviewed. Schiit has come a long way on objective performance. Question remains as to build quality.

Other than some really tight screws, taking the unit apart was easy and shows care in reducing cost. Putting all the components on one side helps a lot too.

Here is the main PC Board:

The architecture is quite simple. AC input becomes rectified, cleaned up with the caps and then regulated using the LM series variable regulators. High quality Japanese Nichicon capacitors are used here as well as the rest of the amplifier. Temperature rating is 85 degrees C as opposed to higher grade, 105. In this application though, I am fine with that as I did not detect the unit getting warm enough to cook the capacitors.

Input signal then goes...

I previously reviewed the Nord One NC1200DM Signature Stereo class-d amplifier. Here is a brief tear down of the same.

The NC1200Dm is a "dual mono" configuration with two power supplies, two hypex NC1200 amplifier modules and two NORD designed "buffer" (preamplifier) stages:


As I noted in the tear down of the Nord Three Purifi amplifier, I am not happy with the pair of voltage regulators in the buffer boards hanging in the breeze. Those heatsinks should be larger/heavier and soldered to the PC board.

I don't understand why the buffer stages are sandwiched between the noise power supply and power amp. They should be to the back of the unit.

I am pleased that no double stick tape is...

Recently I reviewed the Nord Three SE 1ET400A Dual Mono Stereo Amplifier. That unit came with the Sonic Imagery's 990ENH discrete operational amplifier ("opamp") in the buffer stage (pre-amplifier). The owner then ordered a set of Sparkos Pro SS2590 discrete opamps. This gave me a chance to compare the two in the same platform.

Alas, this analysis while of some value, won't be conclusive as power amplifiers can have temperature and run to run variations. Still, the Purifi 1ET400A modules are very low distortion so the data is more likely to be valid than not.

The opamps are socketed in the buffer board provided by Nord making swapping out easy. I especially appreciated the beefy gold coated pins which made it easy to pull them out and insert. Here is the original configuration with Sonic Imagery 990ENH:

...

This is a review, detailed measurements and comparison of Schiit Magni 3+ and Heresy Headphone Amplifiers. It was kindly sent to me by the company. They both cost US $99 plus shipping from Schiit.

The Magni 3+ is a discrete amplifier implementation whereas the Heresy uses integrated circuits ("opamps") creating a race as to which is better.

Both units come in classic Schiit enclosure but the Heresy has burgundy accent with black top:

The Heresy has a nice red LED indicating if the power is on or not. The Magni 3+ does not. Why? Half the time I could not tell if the Magni 3+ was on or not.

The volume control on both is rather close to the 1/4 headphone jack. As such, even though I have thinner fingers, I could not comfortably change the volume control. Wish the headphone jack was on the left side and volume on the right.

Both units are powered by the classic AC transformer (15 volts AC @ 1.5 Amps) Schiit ships with a lot of...

This is a review and detailed measurements of the Soncoz SGD1 Audio DAC. It was kindly sent to me by its designer. You can be forgiven for not knowing this brand. It is a new company formed by our member @Ben1987 who had previously designed the super popular Khadas Tone Board DAC! He has left and designed this much higher tier DAC. The SGD1 costs US $469.99 plus shipping from Amazon.

The design is unique for a desktop DAC:


The volume control is a rotary encoder. The ring around it indicates volume level. I sort of expected a numerical display to the left of it. You can easily set the input and filter types by how long you push the encoder in, and then rotating it.

Lots of inputs and outputs are available:


Nice to see Coax output and USB-C jack.

I don't see an external antenna but there is Bluetooth and one of the videos indicates Wifi capability!

DAC Audio...

This is a review and detailed measurements of the Vantec USB Audio Adapter NBA-120U. It was kindly sent to me by a member. This thing has both microphone input (and hence ADC) and DAC+headphone amplifier. You get all of that including Prime shipping from Amazon for just US $10! Could be the bargain of the century....

The design departs from the usual shapes in a good way:


The unit is plug and play with windows. Alas, I could not get the ADC input to be recognized properly by my ASIO driver interface I have to use. Did not try to dig further to get it to work. Playback worked fine though so that is how the measurements are performed.

USB DAC Audio Measurements
As usual we start with our dashboard. Usually I drive the DAC at full digital amplitude ("0 dBFS") but the Vantec seriously distorted the output that way. So I dialed it down until that limit went away:



SINAD (measure of noise and...

This is a review and detailed measurements of an "old friend," the Speaka portable USB DAC and Headphone dongle. I say old friend as it is one of the first devices I tested and I gave it high marks. The unit was donated to me from a member in Germany. Shortly after the unit was no longer available at least in US. But another one, the
XtremPro X1-1 seems to be the same guts and is available for US $31 from Amazon including prime shipping.

I was requested -- and literally bribed with money -- to remeasure the Speaka with my new analyzer and metrics so comparisons become easier.

If you have seen one dongle, you have seen them all:


There are a couple of LEDs on it but I did not pay attention to what they do.

USB DAC Audio Measurements
Here is our usual dashboard:


I had to dial down the input by 1 dB as otherwise it clipped and performance dropped good bit.

SINAD (distortion and noise) is...

This is a review and detailed measurements of the original Schiit Modi DAC. It was sent to me by a member who was anxious to have it measured. I said not but that I would be open to a bribe to think otherwise. And the bribe came so here we are. If you are not interested in tests of these older products, please move along. I need money and will do anything to get some!

The original Modi DAC came out in 2013 I think at the same US $99 price that today's products come in as. At that time though, $99 was more of an amazing price for DAC than it is today. The enclosure of the unit looks just like today's DACs:


Schiit has over the years changed the color/texture of the enclosure so it may not match your modern Schiit gear. I think there are still variations even among the new gear. Not sure.

The back of Modi 1 has the bare minimum of connections:
This is all the functionality I need...

This is a review and detailed measurements of the Nord One NC1200DM Signature Stereo Amplifier. It is on kind loan from a member. With the options as tested, the cost is US $4,212. As the name indicates, the amp is based on Hypex NC1200 class D amplifiers plus some value add in the form of Sonic Imagery 990Enh buffers, very fancy speaker terminals and even directional fuse from Synergistic Research!

The enclosure is the same elegant design I have tested before with Purifi modules:

And here is the back panel connectivity:

The massive speaker terminals had no trouble handling my heavy speaker wires.

The trigger input is unusual in that it is supposed to fully shut of the unit, consuming no power (?).

The amps are mounted to the bottom of the case as is...

This is a review and detailed measurement of UpTone Audio's Ethernet "audiophile" switch. It is on kind loan from a member. The EtherRegen costs US $640.

The EtherRegen as the name indicates, "regenerates" and Ethernet signal. This is a functionality that is provided with any Ethernet switch that exists in the market. There are however claims of improvement which I will get into later. For now, the EtherREGEN comes in the same small aluminum enclosure rest of UpTone products come in:

Even though this seems to be the "back," it is the business end of the unit in that it has one special port ("B") that is supposed to be isolated from the ports on the other side:

The power supply is private branded but I am assuming that is just a sticker and UpTone has not really applied for FCC and regulator certification itself. This always puzzles me as companies like UpTone make a lot out of noise...

This is a digest of an interesting study I posted elsewhere on the impact of color on our perception of loudness. It is based on the paper presented at the International Congress on Acoustics (ICA):

Colour-influences on loudness judgements
Daniel Menzel, Norman Haufe, Hugo Fastl
AG Technische Akustik, MMK, Technische Universität München, Germany

Hugo Fastl is one of our authorities on psychoacoustics so when he talks, or rather writes, I take notice .

The test was simple enough:


In a nutshell, the listener would have to determine how loud something is while a color image was displayed in front of them on the LCD monitor. Different images were used for each trial. I will just post the one using controls that may be on some audio gear:

Depending on the color of said control, this is how the perception of identical sounds...

This is a review and detailed measurements of the Matrix Audio HPA-3B Balanced (input and output) headphone amplifier. It is on kind loan from a member. Even though the HPA-3B still a current product, I can't find a reliable price for it. Seems to have gone for less than US $500 and came out in 2017 I think. [edit: it came out in 2015]

Like the HPA-3U, the HPA-3B comes in a beefy and very deep enclosure:

The volume control is a bit stiff and slippery for my taste.

The gain control is in the back unfortunately:

Inclusion of AC mains power supply though is very nice in the way it declutters your desk.

Note that unlike the HPA-3U, there is no DAC in this unit. Nor is there any RCA inputs. The latter can be easily solved though with an XLR to RCA cable...

This is a review and detailed measurements of the AudioQuest JitterBug USB data and power noise filter. It is on kind loan from a member. The Jitterbug costs US $60 from Amazon including prime shipping. I purchased a JitterBug back in 2015 when it had recently come out and my measurements showed it to have no positive effect. If anything, it seemed to add some noise that wasn't in the output of the DAC. As if to get revenge, my dog got a hold of it and chewed up the case but magically, the circuit itself survived! Anyway, this is a second look at a non-chewed up version.

The Jitterbug is an inline USB device with non-remarkable look:


You just put it inline with your USB cable and it performs its magic. That magic is this according to AudioQuest:


From prior testing of other USB decrapifiers, if real error is induced in USB transmission, the result is severe static and audible flaws...

This is a review and detailed measurements of the Focusrite Scarlett 2i2 Audio Interface (DAC/ADC). I was talked into buying it recently. The 2i2 costs US $140 including free Prime shipping so very reasonable for amount of functionality.

For a budge device, the Scarlett 2i2 looks pretty good:


Yes, I have left the plastic cover on the front and back. Leaving it there in case I decide to sell the unit.

I found the controls more logical than Behringer budget products. Like the separate volume control (small one) for headphone and the larger one for the line out for example.

The inputs are kind of strange in that depending on what type of cable you use, the gain changes. If you use XLR, it assumes microphone input and hence higher gain. If you use TRS/1/4 inch plug, then it assumes "line" input. This works but you better have the right cables to mate with it this way.

The back panel doesn't have much other than a USB-C...

This is a review and detailed measurements of the Hegel HD12 DSD USB DAC and Headphone Amplifier. It is on kind loan from a member. The HD12 came out in 2015 and cost US $1,400. It is now discontinued.

While the enclosure is the typical understated Hegel design, it seems too plain and uninteresting to me:


The remote is the dirt cheap units with membrane keys. It weighs nothing and can be easily lost. Only the lower buttons work with the DAC even though one would think the filter button would be useful here.

The 7-segment LED display is of course quite primitive but does the job.

The back panel shows lousy attention to fit and finish:


The case is literally bowed up in the middle because of some kind of foam insulation. The sharp edges of the stamped steel has no place in such an expensive DAC.

For testing, I downloaded their drivers as the standard one truncated to 16 bits with...

This is a review and detailed measurements of the vintage Audio Research D300 Power Amplifier. It is on kind loan from a local member. The D300 came out circa 1995 and initially cost US $3,500 but then price rose to US $4,000. Quick search shows used ones going for US $1,500.

The D300 is built like a tank:


I am confident you could drive over it and nothing will happen to it. Even the handles are massive which is a blessing as an ultra heavy transformer sits vertically behind the front panel. I could carry the D300 by myself so it is not too heavy to be unmanageable.

The back panel is as you expect:

With one exception: the non-detachable power cord. What is there though seems amply sufficient as it is supple yet quite thick.

Heatsinks are very thick gauge and in use, they got warm but not hot. The rest of the case got warm as well. The amp never complained no matter what I did to...