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

Review and Measurements of QuantAsylum QA401 Audio Analyzer

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This is a review and detailed measurements of the QuantAsylum QA401 audio analyzer. It was kindly sent by company principle and member, @QAMatt. Despite being a total hardware and software solution, the QA401 is ridiculously low priced at just US $449. To put things in perspective, my Audio Precision APx555 retails for US $28,000. Even cheaper models in their range and from Prism Sound clock well over US $5,000.

The QA401 comes in a surprisingly small package:

QuantAsylum Analog Input Audio Analyzer Review.png

It is no bigger than many desktop DACs and headphone amps. Better yet, the unit is entirely USB powered although it apparently pushes the limits of USB. I had no issue driving it with the USB 3 hub built into my monitor that I use for testing USB products.

The outputs and inputs are differential but in the form of dual BNC rather than XLR. If you use just one leg, then you need to put termination for the other which is what you see in the above setup.

Of note, there are...

Review and Measurements of Audiophonics I-Sabre V4 DAC

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This is a review and detailed measurements of the Audiophonics I-Sabre V4 DAC "HAT" for Raspberry Pi single board computers. It was kindly sent in by Audiophonics for review. The cost without VAT is 58.25 Euros which translates into US $58.25.

The I-Sabre V4 looks unusual as far as layout:

AUDIOPHONICS I-SABRE V4 Raspberry Pi HAT DAC Audio Review.jpg

A lot of board space is dedicated to the 3-pin IC to the center left. Lots of via stitches are used to allow the PC Board to act as an efficient heatsink.

There is a socketed 1701 op-amp which I assume allows people to scratch the itch of modding such devices. There is a proper oscillator in that larger "can" enclosure feeding the little ESS ES9023 DAC chip close to the RCA connectors. Speaking of those, as you see in the picture, they are quite beefy and high quality. And the large nut should allow secure connection to an external case.

There is a connector on the left for a display and different headers for switches and such.


Review and Measurements of Aoide DAC II Pi HAT

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This is a review and detailed measurements of the Aoide DAC II Raspberry Pi HAT DAC. It was kindly purchased by a member and drop shipped to me. He bought it from Amazon and it costs US $39.99 including Prime shipping. It uses an ESS ES9018K2M DAC Chip unlike the competing budget DACs which use the TI PCM series DAC.

Here is a shot of what it looks like:

AOIDE DAC II ESS ES9018K2M Raspberry Pi HAT DAC Audio Review.jpg

The Aoide DAC II has some of the cheapest RCA connectors you can imagine. I worried they would snap off as I inserted my test RCA cables into it that don't require much tension. Can't imagine using "audiophile" ones with their death grip on them.

There is a 3.5 mm jack in addition to RCA but they are hooked up to each other from what I can tell. This means it has high impedance and low power so don't use it for proper headphone listening.

As with recently Raspberry DACs, I used the same Pi board running Ropieee Roon player endpoint. So all the tests are done with Roon...

Review and Measurements of AUDIOPHONICS DAC I-Sabre ES9038Q2M

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This is a review and detailed measurements of the AUDIOPHONICS DAC I-Sabre ES9038Q2M Raspberry Pi DAC. This was kindly sent to me near a year ago by Audiophonics. The DAC I-Sabre ES9038Q2M cost 129 Euros from Audiophonics direct. I don't know if anyone sells it cheaper or not. Edit: US price which excludes VAT is $118.

The ESS ES9038Q2M chip certainly requires a lot more parts than we have seen in other Pi HATS:

AUDIOPHONICS ES9038Q2M Raspberry Pi DAC Sound Card Audio Review.jpg
I should say that it is a pain to identify these products as a number of them have no markings at all on the board as to who made them or what the model number or revision is. I have had to do a visual match of the components to determine this.

For my testing, I used the identical setup to recently tested PI DACs. I simply replaced the DAC, selected the appropriate driver in Ropieee software that runs on the Pi and tested the unit.

I expect good results here since Audiophonics includes Audio Precision FFT results...

Review and Measurements of PiFi DAC+ Pi Sound Card

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This is a review and detailed measurements of itead's PiFi DAC+ Version 2 Raspberry Pi sound card (DAC). It was kindly purchased by a member and drop shipped to me. It costs US $40 but company has it on sale for US $36.50. It competes with the HifiBerry DAC+ whose pro version I recently reviewed. Unlike that unit, the PiFi DAC+ does not have independent clock source and must be using I^2 S clock. It is said that this clock has more jitter so will be interesting to see if that is the case in measurements.

Here is what it looks like:

iTead PiFi DAC+ Raspberry Pi DAC Audio Review.jpg

The common TI PMC5122 DAC chip is used which retails for $2.40. So not hard to imagine how these things sell so cheaply. There are a few extra bits on this such as a post regulator an IR input port and a 3.5 mm jack. The latter is just mirroring RCA connectors and as such, has...

Review and Measurements of HifiBerry DAC+ Pro XLR

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This is a review and detailed measurements of the HifiBerry DAC+ Pro XLR. It was kindly purchased by a member and drop shipped to me. It costs USD $59.90 which is quite cheap for balanced output. I think the cheapest stand-alone DAC with XLR output that I have tested was US $150 (Massdrop Grace SDAC Balanced). Even including the cost of the Raspberry Pi, you are less than $100 here and you get streaming functionality to boot.

Here is what it looks like:

HIFIBERRY DAC+ PRO XLR Audio review.jpg

The giant XLR connectors dwarf the rest of the board. They are sturdy though and had no trouble supporting the weight of my XLR cables although the rest of the unit as you can imagine, is quite unstable. You would need to weigh it down somehow to keep it from following the XLR cable to the ground or wherever it goes. :)

The Pro designation in the name...

Review and Measurements of HiFiBerry DAC+ Pro

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This is a review and detailed measurements of the HiFiBerry DAC+ Pro DAC for the Raspberry Pi boards to build your own low cost streamer. The unit was purchased and drop shipped to me by a kind member. The HiFiBerry DAC+ Pro costs just USD $39.90. So you could have a streamer and DAC for just US $70 or so.

The HiFiBerry DAC+ Pro distinguishes itself from the lower cost versions by having dual clocks to produce low jitter performance. The board is basically a TI PCM 5122 and a few passive parts and connectors plus aforementioned clock:

Hifiberry DAC+ Raspberry Pi DAC Audio Review.jpg

It comes with a set of stand-offs but you are on your own to provide a case and power supply for the combined boards. I used a switching power supply for my testing.

I performed my testing using Ropiee custom Linux install that simply provides a Roon endpoint. As such, I used my Roon player to send the bits to it. The initial install did not work and I had to mess with it by remote login using...

Review and Measurements of xDuoo TA-10 Tube DAC & HP Amp

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This is a review and detailed measurements of the xDuoo TA-10 DAC and Tube headphone amplifier plus pre-amplifier. It was kindly sent to me by the online store, Xtenik Audio. The TA-10 costs US $290.

I must confess, my impression of xDuoo is one of ultimate budget products, with looks and performance to go with that. So I was hesitant to accept this review when Steven from Xtenik Audio reached out to me. I warned him that I would write the review as I see it, bad or good. To my pleasant surprise, he was perfectly OK with that. So here we go.

Everything I thought about xDuoo as a brand went out the window when I pulled the unit out of the box and noticed its attractive and high build quality:

xDuoo TA-10 DAC and Headphone Amplifier Audio Review.jpg

The rotary control feels nice and very responsive. The gold accent on the 1/4 inch headphone jack adds some interest to the black face. The XLR output is for convenient, not for "balanced" output...

Review and Measurements of NAD C 320BEE PWR Amplifier

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This is a review and detailed measurements of the NAD C 320BEE power (speaker) amplifier. It is on kind loan. The C 320BEE is a vintage product, dating back to 2003 I think. The BEE designation is apparently a reference to Bjorn Erik Edvardsen who was one of their designers. Can't tell if he designed this version or this is based on work he did years earlier. Either way, I am told it is a "classic." I don't keep up with such things but I am sure some of you will set me straight if that is, or isn't so. :)

From what I can tell the original cost was US $399. So quite a budget piece for a mid-tier brand like NAD.

The C 320BEE is typical of NAD design language which is maintained to this day:

NAD C 320BEE Integrated Amplifier Audio Review.jpg

There are set of tone controls and balance which I appreciate in this day and age when it is removed from most gear.

I did not seek out the manual and remain unsure how this thing powers on. You hit the power button but nothing happens...

Review and Measurements of Massdrop Grace SDAC

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This is a review and detailed measurements of the Massdrop Grace Design budget DAC. I reviewed it when it first came out but it was with my old audio analyzer so it was requested I measure it again. As it happens, two members kindly sent the SDAC in at the same time! When available the SDAC costs US $70.

The SDAC as minimalistic as you can get:

Grace Design SDAC Audio Review.jpg
The back panel follows the same theme:
Grace Design SDAC back panel Audio Review.jpg

Micro-USB input and RCA plus 3.5 mm output finish the story. This suits me fine because there is less to test. :D

DAC Audio Measurements
Let's start with our usual dashboard:
Grace Design SDAC Audio Measurements.png

The output is a healthy 2.2 volt which is nice (nominal is 2 volt). What is not so good is the THD+N and hence SINAD (signal over noise and distortion). At an...

Review and Measurements of Gustard H10 Headphone Amp

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This is a review and detailed measurements of the Gustard H10 Headphone Amplifier with balanced input. It is on kind loan from a member. Seems like the H10 was released back in 2015 and is no longer available. It is listed for US $399 on some sites with no stock.

The H10 is quite large and heavy for a headphone amplifier:

Gustard H10 Headphone Amplifier Audio Review.jpg

The volume control is large which is nice. What is not so nice is its stiff feel despite the size of that knob. As shipped, the knob would slide past the max and min so I had to readjust and tighten the screw. Alas, the volume control shaft is round instead of notched so this problem will remain.

There is only a power switch and a 1/4 inch headphone jack.

Here is the back panel:

Gustard H10 Headphone Amplifier Back Panel Audio Review.jpg

As you see, there is a set of XLR inputs in addition to RCA. There is a dip switch to seemingly select between them but it doesn't do that. Instead, it just sets the gain appropriately...

Review and Measurements of E1DA 9038S BAL Portable DAC & Amp

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This is a review and detailed measurements of the E1DA 9038S portable balanced DAC and headphone amplifier. It is the brainchild of the member @IVX. He kindly sent me a sample for review. The cost is stated as "TBD($70)." He will have to tell us if the price is finalized or not.

The 9038S looks like most "thumb drive" DAC and amps with a USB-c connector at one end. Where it departs is that its output is only balanced 2.5 mm jack:

E1DA Portable DAC and Balanced Headphone Amplifier Audio Review.jpg

Given the 2.5 mm, 4 conductor jack, you must use a "balanced" headphone cable with it.

There is a blinking orange LED that shows USB activity that I like. It is not very bright so should not be a bother.

The 9038S weighs essentially nothing. It gets a bit warm but nothing of concern.

There are no volume controls so you have to use the controls in your operating system/player.

@IXV has an audio precision analyzer (series 2) and its claim to fame is very good measurements. BUt...

Review and Measurements of Schiit Valhalla 2 Headphone Amp

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This is a review and detailed measurements of the Schiit Valhalla 2 headphone amplifier. It is on kind loan from a member. The Valhalla 2 costs US $349 from Schiit itself.

I recently measured the older and discontinued Schiit Valhalla. This is what Schiit says about the improvements:


As you can imagine, the look and feel of the Valhalla 2 is almost identical to other Schiit units:

Schiit Valhalla 2 Tube Headphone Amplifier Audio Review.jpg

The volume control is large and feels good.

I am not going to bother showing you the back as it is just a input and RCA outs mirroring the headphone out. And built-in mains power supply.

The Valhalla had the worse distortion metric of any headphone amplifier I have tested. Has the Valhalla improved? Let's find out.

Headphone Amplifier Audio Measurements
I set the unit to low gain, fed it 2...

Review and Measurements of Weiliang Volume Control

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This is a brief review and measurements of the Weilang Volume Control and remote control input switcher. It also has a Bluetooth interface built-in. It is available on Aliexpress for under US $40. A member of our local audiophile society brought it to our meeting today for testing.

The case is budget category but still metal with built-in mains power supply:

Weiliang Audio Remote Controlled Volume Audio Review.jpg

Seems like a lot of companies brand this product. Here is a picture of its guts from the Aliexpress seller:

It is impossible to fathom how such a device can be built and sold for so little money.

There is a remote control which I did not see or play with.

The heart of the unit is the TI PGA2310 volume control IC. It has very good specs:


That is SINAD of 107 dB. Let's see if it gets there.

Audio Measurements
I tested the unit with 2 volt at max volume...

Review and Measurements of Sabaj D5 DAC & Amp

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This is a review and detailed measurements of the Sabaj D5 DAC and balanced headphone amplifier. It was kindly sent to me by the company. The D5 costs US $470 on Amazon in US. It uses the top of the line, ESS ES9038Pro DAC chip. So in theory, performance should be excellent.

The D5 is fairly typical of DACs at this price point although some attempt has been made to make it more unique:

Sabaj D5 DAC and Headphone Amplifier Audio Review.jpg

There is a very sharp OLED display. Alas, the font is small which is fine for menu adjustment. For status display as you see above, I wish they had used much, much larger font for the volume level instead of that large symbol.

There are both 1/4 headphone output and 4-pin "balanced" XLR headphone out. You have to select each one separately in the menu together with Line Out in the back.

The menus are easy to navigate with the click button and wheel. Hold the button down to exit the current menu.

A remote control comes with it which I did not...

Review & Measurements of Talema Relay Pre-amp

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This is a review and detailed measurements of the Talema power Volume Remote Control Relay 128 Steps Constant input impedance 4 CH passive pre-amplifier. It is on kind loan from a member. You can find it on various online sites. An ebay listing shows it costing US $130. Given the four channel input and remote control, it seems like very good value.

The box won't win any design awards but is solid metal as is the remote:

Talema power Volume Remote Control Audio review.jpg

The knob on the left selects input and the one on the right changes volume. Max volume level is 128 by the way, not 100.

The remote is ugly but is made out of heavy metal. It has nice little green LED that comes on when you press any buttons.

The back panel is as you would expect:

Talema power Volume Remote Control Back Panel Audio review.jpg

The inclusion of power supply inside the box makes things tidy but of course, there is NO regulatory certification. The picture on ebay listing does NOT show proper grounding of the...

Review and Measurements of Schiit Valhalla Amp

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This is a review and detailed measurements of the Schiit Valhalla tube headphone amplifier. It is on kind loan from a member. The unit is discontinued. I think it came out in 2011 (?). From what I can tell, the cost was US $450 or so.

The sample I have has been through some war duty but otherwise matches the look of typical Schiit products:

Schiit Valhalla Tube Headphone Amplifier Audio Review.jpg

The volume control has a good feel.

There is nothing in the back but a set of RCA inputs, power and on/off switch so I will not be posting a picture of that.

The driver tubes were 6H1N Russian tubes. The output tubes were 6H6N.

The unit is very heavy for its size and gets incredibly warm.

Not much else to the unit so let's get into measurements.

Headphone Audio Measurements
Here is our usual dashboard:
Schiit Valhalla Tube Headphone Amplifier Audio Measurements.png

Even though I am at just 2 volt output, distortion was through the roof. I thought something was broken by Shiit specs the unit at 0.5% distortion so...

Review and Measurements of Schiit LYR 2 Amplifier

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This is a review and detailed measurements of the Schiit LYR 2 tube Headphone Amplifier and Preamplifier. It is on a kind loan from a member. The LYR 2 is discontinued but was a very popular device for its time. I think it sold for US $449 when new.

The unit fits the typical mold of Schiit products:

Schiit LYR 2 Headphone Amplifier Preamplifier Tube Audio Review.jpg

There is nice, heavy feeling volume control in the front and 1/4 inch headphone jack.

The owner was kind enough to not only send me his set of Octal LISST solid state tubes and a set of 6BZ7 tubes. I tested both. FYI I spelled the solid state tubes "LSST" in my slides.

The back of the unit is self-explanatory:

Schiit LYR 2 Headphone Amplifier Preamplifier Tube Back Panel Audio Review.jpg

I though the output was a real pre-amp but seems to be a direct tap from the headphone out (possibly with an inline resistor).

A power supply is included in the unit which makes it very heavy for its size.

In use, the LYR 2 cooks and cooks good. The entire chassis but...

Review and Measurements of Grace Design Balanced DAC

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This is a review and detailed measurements of the Massdrop Grace Design Standard Balanced DAC. It was announced a long time ago and finally became available last week at which time, I purchased it. It costs US $150. The initial quantity of 472 got sold in two days so you have to wait if you want to buy it.

The Balanced DAC enclosure is similar if not identical to the classic "O2" DACs:

Massdrop Grace Design Balanced DAC Audio Review.jpg

There is a switch for USB input versus optical/coax. The business end is the rear:

Massdrop Grace Design Balanced DAC back panel Audio Review.png

A pair of XLR balanced connectors is the reason for anticipation for this DAC. I think it is the cheapest brand name DAC with balanced output at this price.

For my testing I used USB. There is that combo 3.5 mm coax/toslink which I don't like as I seem to never find my special cable for that. However, it is better to have it than not.

Despite the name, there is also unbalanced output but it too is 3.5 mm jack. These...

Review and Measurements of Totaldac d1-six DAC

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This is a review of the Totaldac d1-six DAC and headphone amplifier. It was kindly shipped from europe to me for testing by a member at a high shipping cost of over 200 euros. The d1-six costs 13,500 euros including VAT in Europe and $12,400 for export. The latter translates into US $13,816. This is the most expensive DAC to be reviewed as of this writing.

The d1-six is a two-box solution with the power supply in an external box:

Totaldac D1-six DAC and Streamer Audio Review.jpg

The black plexiglass is meant to give it a touch of class but it is not very successful. I darkened the image above to get rid of the myriad of reflections it shows. The trapezoidal case is not my cup of tea either, in this product or elsewhere.

The yellow OLED display is nice but too small for viewing in a main system configuration. Strange to see 44.1 kHz sampling shown as 44K1. This convention (replacing the decimal point with the unit) is used among engineers sometimes when giving measurements of...
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