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

Review and Measurements of Asus Xonar U7 MKII ADC/DAC/HP

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This is a review and measurements of the Asus Xonar U7 MK II multi-channel DAC, Headphone Amplifier and Analog to Digital (ADC) converter. A member overseas prompted me to purchase this unit to test by donating to the forum nickel jar. :) At just US 90 on Amazon with prime shipping, this is quite a bargain if it lives up to its specifications.

From the outside, the U7 leaves a very positive impression:

Asus Xonar U7 MK II Audio Review.jpg

There is somewhat nice feeling rotary control for volume control. Alas, it is just changes the PC/Windows volume level so don't expect it to have good resolution. It is clickable and selects between "speaker" (really line out) and headphone out. There is also a S/PDIF out but only controllable through their app.

The back panel shows the connectivity and continued good looks:

Asus Xonar U7 MK II Back Panel Audio Review.jpg

Overall the hardware leaves a very good impression despite the plastic housing and such. Sticky feet keep the...

Review and Measurements of Benchmark HPA4 Headphone Amp/Pre

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This is a review and detailed measurements of the Benchmark HPA4 headphone amplifier and preamplifier. The company was kind enough to loan me one for testing. The HPA4 retails for US $2999 so not cheap. It is a collaboration between Benchmark and THX to implement the "888" standard. Will it outperform the much cheaper THX designed Massdrop/Drop AAA 789? That is what we will attempt to determine later in this review.

The HPA4 is a departure from other Benchmark products with the addition of a color touchscreen:

Benchmark HPA4 Preamplifier and Headphone Amp Audio Review.jpg

The screen looks better in person (and in my picture) than what I have seen elsewhere. Still, it is a juxtaposition of industrial/professional look.

The display does not do a lot but hugely simplifies the configuration of the HPA4.

Volume control is a stepped attenuator implemented with a ton...

Review and Measurements of LG G5 Hi-Fi Plus DAC/Amp

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This is a review and detailed measurements of a bare board LG G5 Hi-Fi Plus DAC and headphone amplifier. As the name indicates, it is an accessory piece for the LG phones to increase performance. However, it seems that it is available as bare board which is sold in Asia for as little as US $20. A member kindly purchased one of these and sent it to me.

The version I have came in a clear case which is much needed given the delicate nature of the two board solution:

LG G5 Hifi Plus Headphone Amp and DAC Audio Review.jpg

The included case does not do a good job of containing the USB-C connector which moves with ease as the cable moves (not good).

I was unhappy with the cut-out for the headphone jack as it did not allow me to use many of my cables. It requires a skinny headphone plug which fortunately is the case with many modern headphones.

Typical of these devices, there is sensing of the headphone jack to both enable the device to function and also set the output voltage. You have to...

Measurements of COWON PLENUE L DAP

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PLENUE is High Fidelity audio brand of "COWON" wich is once a leader in the MP3 market with iriver. It is a brand that corresponds to the Astell&kern(AK) of iriver. PLENUE L is PLENUE's flagship product. PLENUE is only a DAP that is specialized for sound reproduction. It uses embedded Linux instead of Android, and there is no wireless communication function including BT, WIFI, NFC. The price is lower than AK, despite the amazing performance.

Below is a diagram of my equipment.

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I use apple music to explore new music, but I don't use it frequently. Because I like to own music rather than streaming. PLENUE L has 256GB of internal memory and a micro sd card slot which can expend to 2TB, so I can store more music than my own macbook pro.

I also set up PLENUE L to build a complete silent system. Combine with a stand-alone DAC, the LYNX HILO, to get rid of PC fan noise and HDD noise.

In speaker system, PLENUE L and LYNX HILO...

Review and Measurements of Schiit Mani Phono Stage

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This is a review and detailed measurements of the Schiit Mani Phono stage/pre-amplifier. I was prompted to purchase it a while back due to its popularity. The Mani costs US $129 plus shipping.

Naturally, the Schiit Mani adopts the look and feel of other Schiit desktop products:

Schiit Mani Phono Preamplifier Audio Review.jpg

I was expecting gain and MM/MC switch but there is none. Instead, dip switches under the unit perform these functions.

A 16 volt, 500 milliamp AC external transformer powers the unit.

The back panel as you would expect:

Schiit Mani Phono Preamplifier Back Panel Audio Review.jpg

There is a stout grounding terminals which I did have to use. Lowest noise/hum was achieved with my Audio Precision analyzer with its unbalanced inputs and outputs fully floating.

Back to the dip switches, there are two stages, each with a High Low setting. So overall, you have a choice of four gain settings. By experimentation, I used High on Gain 1 state and low on Gain 2 for Moving Magnet...

Review and Measurements of SONOS Connect Streamer

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This is a review and detailed measurements of the SONOS Connect Audio/Multi-room streamer. It is on kind loan from a member and costs $349 on Amazon including Prime shipping.

The Connect has the look of earlier SONOS products which is attractive:

Sonos connect streamer Audio Review.jpg

Functionality takes a backseat to looks though as you get to decode blinking LED that can change its color. Better have the manual handy to know what it is saying.

The back panel better shows the capabilities of the unit:

Sonos connect streamer back panel Audio Review.jpg

The only inputs are Ethernet/Wifi and analog in. There is both Toslink and Coax and they are output only. This made my testing quite difficult as my Audio Precision analyzer cannot control such a device.

Initially I fired up Roon and was pleasantly surprised that it saw the Connect and happily streamed my test signal to it. But all of a sudden it started to get errors talking to the box and I could not get it to work no...

Review and Measurements of FX Audio DAC-X7 DAC & Amp

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This is a review and Measurements of the FX Audio DAC-X7 DAC and headphone amplifier. An overseas member was interested in it and donated the shipping cost for me to buy it locally. The cost on Amazon is US $189 with free shipping in US. DAC-X7 uses the same AKM 4490 as Topping DX3 Pro so makes for a good comparison as you will see later. DX3 Pro costs more though but includes Bluetooth.

While typical of this class of products, the DAC-X7 adds a touch of class with a blue display:

FX Audio DAC-X7 DAC and Headphone Amplifier Audio Review.jpg

The display while very small, is more legible than likes of SMSL for example.

The back panel is more or less what you expect:

FX Audio DAC-X7 DAC and Headphone Amplifier Back Panel Audio Review.jpg

There is however an Aux in which I did not have a chance to measure as all of my testing is with USB input.

The external power supply is a...

Review and Measurements of Purifi 1ET400A Amplifier

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This is a review and detailed measurements of the Purifi 1ET400A Class-D amplifier module. Company was kind enough to send me a complete, assembled kit consisting of two modules, power supply and case, ready to go. They have not disclosed the cost of the unit. Modules will be available to DIY channel in Q4 of 2019.

As cases go, the prototype unit came in an attractive one:

Purifi 1ET400A Class-d Amplifier Module Audio Review.jpg

A touch of color on the lid goes a long way to break the monotony of DIY aluminum cases. Someone should take this case, put two giant VU meters in the front and make me happy! :)

Here is a quick teardown:

Purifi 1ET400A Class-d Amplifier Module Teardown.jpg

A single Hypex SMPS1200 is used to power both channels. That feeds two 1ET400A amplifier modules.

A single "Amp Connector Board" feeds both channels using balanced input through an optional gain stage of 13 dB. Here is more detail from documentation on the features of this EVM board...

Review and Measurements of Yamaha WXA-50 Streaming Amp

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This is a review and detailed measurements of the Yamaha WXA-50, multi-function DAC, pre-amp, power amp, streaming and multi-room unit. It is on kind loan from a member. Even though it came out a few years ago (2016?), it is widely available. Amazon shows it costs US $478.

Success of SONOS as a multi-room audio solution has been the envy of many traditional audio companies. Many have tried to chase them with Yamaha being one of the earlier ones.

The WXA-50 is a surprisingly heavy unit although looks somewhat unremarkable:

Yamaha WXA-50 Streaming DAC and Amplifier Audio Review.jpg

The case is metal as best as I can tell which is good as the unit generates good bit of heat. Strangely the heat is concentrated on the left side yet the vents are on the right!
There is an IR hole on the left which confused me to no end, constantly wanting to push it to turn on the unit.

I am not a fan of a single light indicating input and overload condition of the amplifier. Worst part of the interface...

Great Interview with a Music Producer/Engineer

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This is a great interview about the technical ins and outs of studio work. It is with Alex Sterling, owner of Precision Sound studio. He has a very nice, pragmatic, down-to-earth way of explaining things that I like. Very informative and not too long so give it a watch. It covers everything from use of studio monitors and headphones to preference for mixes and such.

Review and Measurements of Denon PMA-50 Amplifier

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This is a review and detailed measurements of the Denon PMA-50 Audio (speaker) amplifier with included DAC and Bluetooth. It is on kind loan from a member. It seems to be discontinued but when available, it cost US $599. I see it on ebay and such from $370 to $450.

The enclosure is more stout and nicer looking/feeling than a lot of products in this category:

Denon PMA-50 Digital Amplifier Audio Review.jpg

The volume control is large and nice feeling. It works a bit odd though in that when you first turn it, it switches the display to volume level but doesn't do anything with respect to changing the level. You need to keep turning it to have it take effect.

There is a headphone amp which I did not test yet. May do that later.

Back panel shows a nice suite of digital and analog inputs but no line out for the DAC:

Denon PMA-50 Digital Amplifier Back Panel Audio Review.jpg

I performed all of my testing with USB and a bit with analog Aux input.

Included mains power supply gets rid of the...

Review and Measurements of New Topping D50s DAC

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This is a review and detailed measurements of the brand new, Topping D50s. Yes, this is a new revision of one of our favorite DACs, the D50. The new version brings Bluetooth, remote control and better performance (see measurements below). It was kindly sent to me by Topping. I don't see an announcement on it but Topping has shared with me that it will cost US $250. The unit I have is production version but lacks manual, stickers and such.

From the outside, the D50s looks pretty much the same as D50:

Topping D50s DAC Audio Review.jpg

You can see the antenna in the back for Bluetooth. The remote control is the same as recently Topping offerings. Indeed I used the one from Topping DX3 Pro to control it. It uses two AAA batteries so there should not be any issue with coin cells.

The back panel is what you expect:
Topping D50s DAC Rear Panel Audio Review.jpg


For my testing, I just used the round 5 volt cable to USB that Topping provided. I simply plugged that into one of...

Great Talk on Design of Benchmark AHB2 and THX Technology

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Someone post this jewel of a video where John Siau of Benchmark and Laurie Fincham of THX talk not only about design of the Benchmark AHB2 amplifier but many concepts in general from dynamic range to content production and speakers. Definitely worth a watch. It is less than an hour so put aside some quality time and listen.

Review and Measurements of Little Dot MK III Tube Headphone Amplifier

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This is a review and detailed measurements of the Little Dot MK III Tube Headphone amplifier. It is on kind loan from a member. It costs US $289 including Prime shipping. The unit has been sitting for a while (my apologies to its owner) so please excuse a bit of dust in the pictures below. I tried to dust them off while the unit was on and the right rear tube burned my finger and burned it good!

A few touches in the industrial design sets this amplifier apart, giving it an elegant, higher-end look:

Little Dot MK III Headphone Amplifier Audio Review.jpg

The volume control has a nice feel -- not too lose, not too tight. And large enough to fit in the hand well. And the unit is heavy enough to stay put and not get dragged around by any wires.

The Little Dot MK III is mains powered which further gets rid of clutter on your desk:

Little Dot MK III Headphone Amplifier Back Panel Audio Review.jpg

The stickers likely don't mean anything as far as safety certification.

I was surprised to see US made tubes in...

Canjam SoCal Headphone and Audio Show 2019 Part 2

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As you may have noticed from my comments on day 1 at SoCoal CanJam, the first day was busy so I could not talk to many industry people. For some reason I thought today would be worse but it was the exact opposite. There were maybe 30% of the number of people on day one. This made the day hugely more fruitful for me in networking, chatting with companies, etc. Some will be reflected in the trip report. Others will reveal themselves in the future. :)

Anyway, my initial mission was to hit the suites that were too busy the first day. And that started with Woo Audio's table, starting with this GES Electrostatic tube amplifier:

6T5A3080.jpg


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It sounded good but like my Stax tube headphone amp, can't play super loud.

The next product was the WA11 Topaz which is a portable DAC and headphone amplifier...

Canjam SoCal Headphone and Audio Show 2019

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So I finished my first day at the Canjam southern california show. I attended three talks and spent the rest of the day mingling among the vendors and visitors.

It is a relaxing show for me compared to the massive ones I usually attend. There was one hall and a few small rooms around it and that was it. Here is the major hall:
6T5A2941.jpg


I was disappointed to just get a wrist-band for admission. No name badge so no one could tell who you were. I had to keep introducing myself and handing out business cards. Manufactures couldn't tell if I was a customer or not without such a name tag. Exhibitors all name tags. Don't know why could not give visitors some, even if it were hand written.

Review and Measurements of VMV VA2 Headphone Amp

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This is a review and detailed measurements of the (SMSL) VMV VA2 Headphone Amplifier. It is on kind loan from a member. It seems to have come out back in 2016 but online sellers are still selling it from USD $96 (Amazon) to $140. So in that sense it competes with the likes of JDS Labs Atom and Schiit Magni.

VMV is SMSL's higher up brand and as such, the VA2 comes in a solid aluminum case that weighs a good bit but otherwise is ordinary:

SMSL VMV VA2 Headphone Amplifier Audio Review.jpg

The volume control can only be grabbed from the top which I found a bit hard to turn and adjust. If the music is too loud all of a sudden, you will have have a hard time lowering its volume as you have to lift your finger when you get to the end of the slot and start over.

The two headphone connectors made me think one had higher gain, and the other, lower gain. Turns out this was a mistake as you see later in the measurements section.

The back panel is simple and has nothing other than an...

Review and Measurements of Sony STR-ZA1100ES AVR

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This is a review and detailed measurements of the Sony STR-ZA1100ES Audio/Video Receiver. It is on kind loan from a local member. It costs US $999. It must have price protection as Amazon price is only $1 cheaper.

Being part of the ES series from Sony, one expects good look and feel and performance. The latter we will see in measurements. Overall, I say it has a more elegant look among the crowded AVR market:
Sony STR-ZA1100ES AVR Audio Review.jpg

Sorry about the dark picture. Took this at night. In person the display is nice and gives the unit a more formal look. There is a panel with magnets that hides all the buttons if you wanted. The volume control has good feel unlike the stiff one I have used.

The back panel is full of connectors as you can imagine:

Sony STR-ZA1100ES AVR Back Panel Audio Review.jpg

For my testing, I focused on left and right channels of the amplifier. For DAC testing, I used Zone 2 output and S/PDIF input.

I did not test HDMI. It is a pain...

Review and Measurements of Audio-gd NFB2 192 DAC

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This is a review and detailed measurements of the Audio-gd NFB2 192 khz DAC. It is on kind loan from a member. It costs US $450 from Audio-gd website.

The overall package while heavy and functional, is not that exciting:

Audio-gd NFB2 192 kHz DAC Audio Review.jpg

The back panel has the usual connection plus the current mode "ACSS" proprietary connectors which I did not test:

Audio-gd NFB2 192 kHz DAC Back Panel Audio Review.jpg

I see no safety or regulatory marks on the unit which is concerning for mains operated units (i.e. NOT using external power supplies).

The unit was plug-and-play on Windows although oddly exposes inputs in addition to outputs! That threw off ASIO4ALL wrapper I use to talk to it in my analyzer. Once I shut down the input, it worked fine.

"NFB" stands for no negative feedback which Audio-gd goes to great lengths to sing its virtues:

1560541700522.png


DAC Audio Measurements
As usual, we start with our dashboard using USB Input...

Review and Measurements of Matrix Audio Element X DAC/Streamer/Amp

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This is a review and detailed measurements of the Matrix Audio Element multi-function audio streamer, DAC, and headphone amplifier. It is on kind loan from a member who purchased it and had it direct shipped to me. As it turns out, the company also contacted me to send me the same unit so kudos to them for volunteering to have their product tested. The Element X cost US $2999.

The Element X leaves a positive impression as soon as you unbox it:

Matrix Audio Element X streaming DAC Audio Review.jpg

There are elegant strips on each side and the case overall fits well in the portfolio of any high-end audio company.

You have dual unbalanced headphone jacks to the left (or balanced pair?) and a single 4-pin for balanced out. The button with circle next to it lets you quickly select rear outputs, unbalanced headphone or both. The latter nicely light up with subtle white LEDs when enabled.

There is a nice high resolution display which as you see indicates MQA content being decoded and...
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