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

Review and Measurements of ifi nano iONE DAC

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This is a review and detailed measurements of ifi nano iONE DAC. It is on kind loan from a member and it retails for USD $199 including Prime shipping from Amazon in US.

The unit is quite "cute" in a small and portable configuration (although somewhat chunky):

ifi nano iONE review.jpg

As you see from the front panel, beside the usual digital audio inputs of USB and S/PDIF coax, it also has a Bluetooth module/input. I will test that feature later. For now, my focus is on the DAC portion.

In addition to analog output, the iONE also outputs S/PDIF over the same digital input connector. It is a trademark of ifi to overload connectors this way, saving space but also creating confusion at times as to how to get the connector to act as one or the other function. As with Bluetooth, I did not test S/PDIF output for this review.

Let's get into measurements and see how she did.

As usual, I start with my Dashboard view of a full amplitude ("0...

Review and Measurements of Schiit Modi 3 DAC

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This is a review and detailed measurements of Schiit modi 3 DAC. It is a replacement for two previous products: the Modi 2 and Modi 2 Uber. I purchased the unit a few days ago for $99 plus $11.26 for shipping for a total of $110.26.

The Modi 3 DAC has the functionality of the latter with three inputs: USB, S/PDIF and Toslink which is nice. A front toggle switch (as opposed to momentary in Modi 2 Uber) selects the input. Schiit has fixed the output voltage so that it is now the full 2 volts as opposed to 1.5 in previous products. They say this is enabled by addition of an external switching power supply which you see here on top of the unit:

Schiit Modi 3 DAC Review and Measurement.jpg

For some reason I think having a black supply would go better with the black USB cord and overall gray look of the unit. Since this is a standard USB supply, I suppose you get your own version in however color or format you like.

Schiit says that this is the best measuring DAC they have...

Schiit Saga Grounding and Hum Issues?

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Readers of the forum probably remember a discovery I made regarding lack of proper grounding for safety and guarding against hum in Schiit Jotunheim. It seems that we may have a repeat of that same case with another Schiit product, the Saga preamplifier.

A forum member reached out to me regarding hum in his Saga preamplifier. He is in Europe and I don't have access to his unit so he sent me pictures of what is inside. Here is the overall shot of the inside of the unit:

Schiit Saga Hum Chassis Not Grounded.jpg

Looking at the chassis, the paint and protective coating remains which means that the top of the unit is likely not making a good connection to the rest of the chassis. As such, hum from the transformer can couple to the volume control just as it did with the Schiit Jotunheim.

Focusing on safety issues, just as well...

Review and Measurements of Fostex HP-A3 DAC and Amp

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This is a review and detailed measurements of Fostex HP-A3 DAC and headphone amplifier. Even though the product is current and listed on both Amazon and Fostex websites, I also found reviews dating back to 2011. So unless there have been some revisions, this is an "older" unit. It is on kind loan from a member and lists for USD $299 with prime shipping from Amazon.

Any memory of Fostex's long history and Japanese lineage goes out the window the moment you gaze at the ordinary and DIY-like packaging of the HP-A3:

Fostex HP-A3 Dac and Headphone Amplifier Review and Measurements.jpg

What is the deal with the huge washer on the headphone jack showing?

Functionality is not bad with USB and Toslink inputs but is missing S/PDIF. I liked seeing the RCA/Phones switch allowing me to test the RCAs as the DAC output. Note that the volume control changes the RCA levels so you can use it to drive active speakers and such, avoiding a pre-amp.

No gain switch is included which I like to see as mandatory feature...

Review and Measurements of iFi Ear Buddy (and iEMatch)

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This is a review and measurements of iFi Ear Buddy which is the cheaper, non-configurable version of iEMatch. I purchased it for USD $20 from Amazon. The purpose of both devices is to reduce the output power of a headphone amplifier. This is needed often when the headphones are too sensitive relative to the amplifier power (or volume control range), not allowing precise control of volume. In addition, many headphone amplifiers have channel imbalances at very low volumes or hiss, both of which are annoying. The idea of Ear Buddy and iEMatch is to reduce the output of the amplifier and with it, eliminate these issues.

The Ear Buddy comes in consumer packaging, hoping to embellish what is ultimately a little cable/dongle:

ifi iematch package review.jpg

Strangely, it has a pair of ear plugs in there. For a moment I thought that was their solution to reducing gain. You stick the ear plugs in your ear and then wear your headphones over that! :D

Even more strange...

Review & Measurements of Allo DigiOne Signature and DIYINHK Pro3Z

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This is a review, detailed measurements and comparison of two S/PDIF digital audio output converters. The Allo DigiOne Signature is a networked S/PDIF converter built on top of Raspberry Pi single board computer. It retails for $239. With the nice acrylic case, it goes for $259:

DIGIONE SIGNATURE PLAYER RPI SPDIF converter review and measurements.jpg

The benefit here is that you can convert any DAC with a S/PDIF digital audio input into a networked DAC. You can place your remote computer/tablet anywhere and have it stream the audio to the Allo DigiOne Signature where your audio system is. The above price does not include the Raspberry Pi which you have to add for a functional system (about $35).

My test system came with "DietPi" packaged Linux distribution for RPi which makes the unit turnkey with native support for Apple Airplay and Roon (RAAT) protocol. As such, I was able to simply power the unit and start playing files to it from my favorite audio player, Roon.

The DigiOne Signature requires two...

Review and Measurements of Oppo HE-2 SE DAC and Headphone Amp

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This is a review and detailed measurements of Oppo HE-2 SE DAC and headphone amplifier. It is on kind loan from a member. Retail price per Oppo website is $299 but I see it as used from $430 and up on Amazon. I wonder if that is because as with their Blu-ray player business, Oppo is getting out producing this device too.

The Oppo HE-2 comes in a luxurious packaging with the unit itself enshrouded in stitched leather:

Oppo HA-2 SE DAC and Portable Headphone Amplifier Review and Measurements.jpg

Intentionally or not, the look at feel of the unit seems to cater more to older clientele than the younger and typical market for headphone and DAC amplifiers.

The unit sports an ESS ES9028-Q2M so it targets high performance.

Boatload of cables and connectors come with the unit which satisfy every type of connection to every device imaginable including selection of right-angle adapters/cables.

I am sure you all are anxious to see how it measures so let's get into that.

Seeing how the HA-2 SE touts its DAC...

Rolling (replacing) Op-amps in Topping D10 DAC

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This is a study of whether changing op-amps in a DAC makes a measurable difference. Taking a lead form "rolling" tubes in tube products, a trend has started in replacing op-amps -- sometimes with much difficulty -- to improve performance of solid state products like DACs. A few months ago I tested the Topping D10 DAC and since it has a socketed op-amp, members asked if I could experiment with changing it to other pin-compatible parts. A couple of kind members supplied me with a good inventory of op-amps to test all the way up to esoteric discrete ones.

Here is the overall circuit diagram:

Topping D10 DAC PCB Board.jpg

You can see how the ESS DAC drives the OPA2134 op-amps that are soldered, providing current (I) to voltage (V) conversion. Their outputs in turn drive a pair of op-amps in the socketed Op-amp (circled) which are our output buffer/op-amps. That is the part we will be replacing.

EDIT: an earlier version of this review mentioned that we were...

Review and Measurements of Chromecast Audio Analog Performance

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This is a follow up to my review and measurements of Google Chromecast Audio's digital performance. As mentioned there, the Chromecast audio is a streaming device with integrated DAC. In the other review, I measured its Toslink digital output for usage with an external DAC. Here, I will be evaluating its analog output performance in case you want to forego the external DAC.

As noted there, the casting functionality of Chrome browser is poor and not bit-exact. So for this testing, I used Roon to play the test files and cast them to Chromecast Audio. This allows bit-perfect functionality so that we can see the performance of the hardware in best light.

The measurements are not extensive as with the digital output because my audio analyzer can't control the Chromecast Audio. But there is enough here to get a good idea of how well it does...
Review and Measurements of Chromecast Audio Digital Output
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This is a review and detailed measurements of Google Chromecast Audio digital output. The Chromecast is a tiny dongle that allows one to "cast" (stream) audio and video to a remote device. The audio version as the name implies, foregoes the video functionality and provides audio streaming. The retail cost is $35.

Chromecast Audio has dual outputs in the same 3.5 mm jack. One is the standard stereo analog. The other, by use of a cable you need to buy, is Toslink digital optical output. The appeal, and the scenario for testing in this article is that by addition of the Chromecast audio to your own DAC using Toslink you immediately turn your DAC into a networked streamer. Concern however has been raised that the Toslink output has too much jitter to be a good interconnect. In this article, I will be digging into this aspect of the device. In a future article I will measure its DAC and analog output performance.

The Chromecast Audio is a tiny round dongle. It has a USB...

Review and Measurements of Allo Boss Raspberry Pi DAC

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This is a review and measurements of the Allo Boss V 1.2 audio DAC for the popular Raspberry Pi single board computer (SBC). It was kindly sent to me by Allo. Retail price as of this writing is $65. The Raspberry Pi retails for $35 so the combination costs about $100. For that, you get a networked DAC in a tiny enclosure.

Allo is one of the few audio companies that performs real measurements of their device and the Boss was no exception. They are also quite active on forums which makes it a plus in my book as far as support and listening to customers. They have been a supporter and long time fan of ASR Forum since inception for which, I am appreciative.

The package as sent to me had both the RPI and Allo BOSS DAC in a cute acrylic enclosure, complete with "DietPi" version of Linux on micro-SD card:

Allo Boss RPI DAC Review and Measurement.jpg

Dietpi is one of a few canned versions of Linux operating system that turns the RPI into a dedicated networked/streamer DAC. It...

Review and Audio Measurement of LG G7 ThinQ Smartphone

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This is the review and measurements of the audio performance of LG G7 ThinQ smartphone. It was purchased by my son a couple of weeks ago. It retails for USD $750. Its claim to fame is inclusion of an ESS quad (four paralleled) DACs ES9218P with integrated headphone amplifier.

LG G7 ThinQ Audio Review and Measurement.png.jpg

There are actually two DACs in there with Quad DAC by default not selected.

LG G7 ThinQ Audio DAC Selection.png

I suspect they don't leave it as default because it uses more power and would hurt benchmarks and battery life.

It even has fancy audiophile reconstruction filter choices:

LG G7 ThinQ Audio DAC filter Selection.png

Default was "short" (apodizing) filter. As seen above, we did our testing using Sharp filter.

Is this all fluff or does it perform? Let's find out.

Let's start with our usual dashboard view of a 24-bit, 1 kHz tone at 44.1 kHz sampling:

LG G7 ThinQ Quad DAC Dashboard Audio Measurement.png

Wow, that is impressive. SINAD...

Review and Measurements of SMSL VMV D1 DAC

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This is a review and detailed measurements of SMSL VMV D1 DAC. It is on a kind loan from a forum member. It retails for USD $1,299 including free shipping on Amazon. It is a super hefty unit, far more than you can imagine from its small enclosure:

SMSL VNV D1 DAC review and measurements.jpg

The box on the left which is permanently attached is the power supply. The bottom of the unit must be made out of lead as the entire thing is heavy.

The heart of the unit is ESS' flagship DAC, ES9038 Pro. Each channel has its own dedicated ES9038 Pro which has 8-channels internally and paralleled for better signal to noise ratio.

The display and functionality thereof are almost identical to SMSL SU-8 which I reviewed recently. In this configuration, it is way too tiny and unfitting of a device this expensive. I appreciate them leveraging what they already had but they...

Review and Measurements of JDS The Element DAC and Headphone Amp

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This is a review and detailed measurements and comparison of JDS Element DAC and Headphone Amplifier. It is on a kind loan from a member. I have been anxious to review one for a while due to attractive industrial design and JDS Lab's typically good work in producing desktop audio products. The Element retails for USD $349 plus shipping.

As noted, this is one nice looking unit and quite a departure from typical hobby box units we see from other companies:
JDS The Element DAC and Headphone Amplifier Review and Measurement.png.jpg

I was going to photoshop out the little scratches and marks but I thought I leave them there to show the propensity to show imperfections.

The ball in the bell is the large volume control. Alas, it feels looser than I had imagined. And while it looks beautiful mounted in the center, I would have wished it was pushed back so that you could rest your hand in front of it. As it is, your hand rests on the rather sharp front edge.

That said, it is very nice in use and has a very large range allowing...

Review and Measurements of miniDSP SHD DAC, DSP And Streamer

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This is a review and detailed measurements of the MiniDSP SHD DAC, audio processor and streaming appliance. It was drop shipped by a kind member to me. It retails for $1195 and it comes with a license for automatic Room Equalization software, Dirac (which I use personally on a PC). It even includes their ever popular measurement microphone:

I only had a few hours to play with it (my fault) so I only measured the DAC portion. Regular readers of the forum may remember my review of miniDSP 2x4 HD. Even though I loved its functionality, its DAC performance left something to be desired.

The miniDSP SHD is quite substantial coming in the 1 RU Rack mountable chassis (indeed it comes with rack "ears"). One of their ever popular measurements mics is...

Review and Measurements of Aune X7s and Arcam rHead Headphone Amps

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This is a review and detailed measurement and comparison of Aune X7s and Arcam rHead headphone amplifiers. I purchased the Aune X7s from ebay for $250. I bought the Arcam rHead used from a member in UK who also bought it used. The total cost to me shipped was £98.55 or $127. The retail price is $599 but I see them advertized for half as much online.

Note: John Dawson, the designer behind Arcam rHead is a long time professional friend and great designer. While I did not let that enter my review criteria, I thought I disclose that out of abundance of caution.

Both of these units are substantial in weight. Quite a bit more than any audio produce in this price category. You can get an idea of their size here:
Aune X7s and Arcam rHead Review and Measurements.jpg

Of the two, the Aune is much more attractive. They brag about getting the industrial design done in UK and it shows. It must be expensive to machine all those curves. Overall it is a very unique look in a sea of ordinary...

Review and Measurements of Allo Katana and ApplePi Raspberry Pi DACs

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This is a review, Measurements and comparison of "high-end" Allo Katana and ApplePi Raspberry Pi DACs. If you are not familiar with Raspberry Pi, it is an ultra-low cost small computer board that runs Linux operating system (primarily). For just $35 you get a full computer with networking, HDMI video output, multiple USB ports and expansion port that allows countless peripherals to be connected to it. These DACs are two examples of high-end audio solutions for "the Pi." The combination of the Pi and these DACs allows you to have a full networked, remote DAC that you can place next to your computer with the media server anywhere else you like. In contrast, few desktop DACs come with built-in networking and require close-in connection to your potentially noisy server connecting over USB.

The Allo Katana has been kindly loaned to me. A bit of background on this. Shortly after I created ASR Forum and started to measure audio equipment, Ioan from Allo contacted me and wanted me...

Do You Need an External DAC/Headphone Amplifier?

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A question is raised from time to time whether one needs an external DAC or headphone amplifier for desktop computer use. I thought I address that with a set of measurements in this article. There will be more to come because unfortunately, there is no one representative computer sound performance.

For this run, I will be testing my everyday laptop which is my main workhorse for a ton of work from listening tests to running my Audio Precision analyzer. It is an HP Z series Laptop that I bought 2-3 years ago at some $2,200. It has a Core i7 processor and is designed for "workstation/corporate" work as opposed to consumer.

As a way of reference I thought I compare its headphone output performance to that of Topping NX4 DSD portable headphone amplifier and DAC. See its review here:

The NX4 DSD retails for $160...

Review and Measurements of FiiO Q1 Mark II Portable DAC and Headphone Amp

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This is a review and and detailed measurements of FiiO Q1 Mark II Portable DAC and headphone amplifier. It is on a kind loan from a forum member. It retails for USD $100 from Amazon including free Prime shipping. The unit is attractively packaged and similar to build quality of Topping NX4 DSD which I used for comparison. Here you see them side by side:


The Fiio Q1 is about 25% smaller in volume so more pocketable than the NX4 DSD. As with Topping, they also have an excellent web page for the unit with the following rich set of specs:


The unit has both balanced and unbalanced headphone output per above. Alas, my balanced test fixture only has XLR (damn these guys for not standardizing on one connector) so I could not test that port.

Let's get into the measurements and see how she does.

Let's start with our usual dashboard in high-gain mode:
Fiio Q1 Mark II DSD DAC and Headphone Amplifier Dashboard Measurement.png

Ah, just 1.5 volt output...

Review and Measurements of Hifime UDA38Pro DAC

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This is a review and detailed measurements of Hifime UDA38Pro DAC which is built on the flagship ESS DAC chip, the ES9038Pro. I purchased this a few weeks ago based on suggestions from members that this is by far the cheapest implementation of ES9038Pro. I paid USD $260 including shipping from Hong Kong. I was told in the confirmation that I would get a tracking number but none came. I complained to Hifime and they never responded but the unit arrived the next day so I did not chase them anymore.

I must say, it is rare that I am so disappointed from the look of a unit as when I received the UDA38Pro. It is a cheesy, China-special box that should be retailing for $20 instead of over $200:

Hifime UDA38Pro DAC Review and Measurement.psd.jpg

As you can see, it is a tiny little box. It can be powered from USB or external adapter which was not supplied. A tiny toggle switch selects between USB and Toslink inputs.

Output is provided in both RCA jacks and 3.5 mm headphone jack. The...
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