Audio Science Review: Articles, Reviews and Measurements of Audio Products

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...

Review and Measurements of Mytek Stereo 192 DSD DAC

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This is a Review and detailed Measurements of Mytek Stereo 192 DSD "mastering grade" DAC. It is on loan from a kind member and was released back in 2012 or so. Its market focus was for mastering engineers and hence that adjective. The retail price was $1,700 at the time. Someone should advise what it goes for used market today.

The unit won't win any beauty contests:

Mytek Stereo 192-DSD DAC Review and Measurement.jpg

It screams old school with that 7-segment display. Machining looks hobbyist although the unit is quite heavy.

The unit strangely supports both USB 1.0 and 2.0 using independent inputs. Plugging in the unit didn't result in it working so I had to install its driver package which gave me the ASIO interface I need for my Audio Precision Analyzer to talk to it over USB. Alas, selection of Mytek ASIO driver would lead to the AP software crashing no matter how many times I tried it, or plug and unplug the USB cable, power cycling, etc. Oddly fortuitously, the ASIO4ALL software layer...

Review and Measurements of Wyrd4Sound Remedy Reclocker

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This is a review and measurements of Wyrd4Sound Remedy Reclocker. It was sent to me by the owner of the Musical Fidelity V-90 DAC and that is how I tested it. It is an older product (circa 2014) although technology like this doesn't change much. Its job is to take S/PDIF input and resample it with a clean clock and output that over S/PDIF. By default the resampling is fixed at 96 kHz according to the company but other sampling rates can be requested. The retail price is $399.

The unit is pretty small, powered by an external switching power supply:
Wyrd4sound Remedy Recklocker Review and Measurements.jpg

It takes either S/PDIF or Toslink and outputs S/PDIF over BNC or RCA jacks. I only tested the latter.

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

Since the unit's claim to fame is reduction of jitter, let's start with a high-resolution FFT of Musical Fidelity V-90 DAC with and without Wyrd4Sound Remedy:

Wyrd4Sound Remedy Reclocker Jitter and Noise Measurement.png

Long time readers of...

Review and Measurements of Topping A30 and Schiit Magni 3 Headphone Amps

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This is a review and detailed measurements and comparison of Topping A30 and Schiit Magni 3 headphone amplifiers. I own both units and their accompanying DACs (Topping D30 and Schiit Modi 2). The review will be mostly covering the amplifiers but at the end, I will provide a snapshot comparison of both units "as stacks" with their DACs. Hey, that rhymes! :)

The Topping A30 is available everywhere and as of this writing costs USD $110 including Prime shipping from Amazon. Schiit only sells its products direct and the Magni 3 costs $99 but then you have to pay shipping which would make the cost comparable to Topping.

Both units are desktop sized as you see here stacked on top of their DACs:
Schiit Magni 3 and Topping A30 Headphone Amplifier Review.jpg

While the "design language" is identical between the two Topping products, as you can see in the picture, the two Schiit units have different finishes. What is that about? Did they change manufacturers for one of the units and didn't try to get...

Review and Measurements of Soekris dac1421 Multibit DAC

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This is a Review and Measurements of Soekris dac1421 Multibit DAC. It is on a kind loan from the designer and forum member, Søren Kristensen. In case you are not familiar with this class of DACs, instead of using an off-the-shelf dac chip, this unit uses a custom implemented DAC using a series of resistors and a custom FPGA (digital logic) controlling them. Technical term for their approach is "Sign Magnitude Discrete R-2R." The dac1421 is unbalanced only and has a retail price of around $1,000 (sold in Euros however).

The unit itself has a simple "design language" and fits in the class as far as fit and finish. Here you see it below SMSL SU-8 which I also tested against it:

Soekris dac1421 vs Schiit Yggdrasil review and measurement.psd.jpg

There is a useful clipping indicator as the volume control can go over reference. For this review, I did not measure the headphone amplifier. Will do that in a future installment.

There is interest in comparing the dac1421 against the Schiit Yggdrasil...

Review and Measurements of Massdrop Alex Cavalli Tube Hybrid (CTH) and JDS O2 Headphone Amps

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This is a review and detailed Measurements and comparison of Massdrop Alex Cavalli Tube Hybrid (CTH) and JDS O2 Headphone Amplifiers. The CTH is on kind loan to me from a forum member. I purchased the JDS Labs O2 last year but have not had time to review it until now.

Alex Cavalli Tube Hybrid (CTH) and JDS Labs O2 headphone Amplifier Review and Measurement.psd.jpg

As the name indicates, the CTH is a hybrid design meaning it uses a tube as a buffer/pre-amp which then drives transistors for output stage. This solves the problem of needing a transformer on the output of the tube amp to bring its impedance down. Like countless designs like it, it uses a low voltage external power brick meaning the tube is not really operating in the region it is designed for. So likely provides little to no gain.

The CTH came beautifully packaged with custom foam inserts in a pretty large package. The unit itself is very attractively finished and gives a feel of quality.
There is a protection circuit which cuts out the output...

Are Measurements of Schiit Yggdrasil DAC Inconsistent?

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It is an understatement to say that my measurements of Schiit products create tons of discussions and arguments across multiple forms. So much so that I think they parallel any reality show on TV! Much of that is driven by passion people have on either side of the fence. What I like to address is the accusation that my measurement techniques are incorrect, or cooked in some ways as to generate unfavorable results for Schiit.

As a way of background, so far I have measured three different samples of Schiit Yggdrasil all from actual customers. You can see the review of the latest one here:

As shown there, the performance of Schiit Yggdrasil DAC is simply not competitive at almost any price, let alone at its retail price of $2399. Importantly though, I always measure two devices side-by-side. This has two benefits:

1. Any errors in measurement technique...

Measurements of Motu UltraLite mk4

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As mentioned elsewhere I have just purchased a Motu UltraLite mk4. I already use a Motu 8A for driving my active 3 way DSP speaker system, however being only 8 channels I am unable to run the centre speaker from it. The EasyLite mk4 caught my eye as it has been upgraded over the mk3 to include the same ESS9016 dacs as the 8A and has the extra 2 channels I require. I have measured the 8A previously and its performance is excellent. The paper specs for the Ultralite claim they have improved the THD+Noise figure by 2dB to 112dB over the 8A.

More info about the product below. Casework is an excellent. Cost is around $595 US.




This just the DAC section, I will test the ADC later.

First off is 1kHz 0dB FS - Note that the noise floor is in reality lower (maybe 20dB) as the Measurement ADC noise floor is...

Review and Measurements of Musical Fidelity V90 DAC

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This is a review and detailed measurements and comparison of Musical Fidelity V90-DAC against Topping D50. The unit is on kind loan from a member who has been patiently waiting for its review. :) The V90-DAC retails for $300 from what I can tell (it is sold through a dealer channel) so a bit more expensive than Topping at $250.

The V90-DAC is quite attractive and has a high-end feel to it despite the diminutive case:

Musical Fidelity V-90 DAC Review and Measurement.psd.jpg

There is a certain elegance to it that you don't normally find in this price category. Compared to it, the Topping looks decidedly industrial.

It comes with a nice little switching power supply no bigger than a USB phone charger.

From format support point of view, the V90-DAC trails the D50 by only supporting PCM up to 192 kHz and no DSD. The Topping goes up to 768 kHz and DSD512. And while the Topping has a volume control, the V90 has none.

Let's get into measurements and see how they do.

Let's start with...

Review and Measurements of SMSL SU-8 DAC

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This is a review and detailed measurement/comparison of SMSL SU-8 DAC and Topping D50. It is on a kind loan from a member who had it drop shipped to me from Massdrop. Since there has been so much interest in this product, I decided to test it immediately.

Overall, the first impression is quite positive. Package is very nice and the unit has quite a heft and quality feel to it. It is a far more substantial unit than the Topping D50 due to inclusion of mains power supply and balanced outputs:

SMSL SU-8 vs Topping D50 Review and Measurements.jpg

The display is kind of tiny but does the job. It came with a remote which is a great bonus (I did not unpack it). The only minor gripe is the very short AC cable. I think it is 2 feet or something as opposed to typical 6 foot. So like me, you may need to supply your own.

The retail price is $249 with free shipping on US Amazon right now. I am assuming Massdrop price was lower. The Topping D50 is also $249 so if the SMSL SU-8 matches its performance, it...

Review and Measurements of Schiit Eitr USB to S/PDIF Bridge

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This is a review and detailed measurements of Schiit Eitr. It is a on a kind loan from the same member that provided me the the excellently performing iFi iDSD Black Edition. It retails for $179 plus shipping from Schiit direct (they don't sell through any other channel).

If you are not familiar with it, the Schiit Eitr is a USB to S/PDIF converter. Yes, Schiit DACs already have USB interfaces but the quality there is not what it should be. So Schiit took the design of their "Gen 5" USB interface from their higher-end units and is providing it in the form of an external USB to S/PDIF bridge/converter.

The Eitr comes in the same enclosure as Schiit Modi 2 series. Here you see it below my Schiit Modi 2 Uber which I used for this review and testing:
Schiit Eitr USB Cleaner and Bridge Review and measurement.jpg

The unit is externally powered...

Fixing Hum/Buzz issues with Schiit Jotunheim Headphone Amplifier

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In my review of Schiit Jotunheim by chance I noticed that the upper part of the case is not grounded. As such, it allowed the transformer to induce hum into the output of the amplifier. Here are the measurements showing such:

A jumper between the drilled holes that are not insulated and the back RCA jack shield got rid of the noise:

This quick article is about accomplishing the same without said jumper.

Note that this is both a performance issue and potential shock hazard. Metal cases on a three-pronged outlet must be security connected to mains safety...

Review and Measurements of Schiit Jotunheim and iFi iDSD Black Label DACs and Headphone Amps

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This is a review, detailed measurements and comparison of Schiit Jotunheim Headphone Amplifier (with its optional Multibit DAC) and iFi iDSD Black Label DAC and Headphone amplifier. Both are on kind loans from members and arrived on the same day. Seeing how their prices are similar, I decided to compare them to each other. The iFi however, has built-in battery, is far smaller and less power hungry, making it suitable for portable use in addition to desktop. The Jotunheim on the other hand, is firmly a desktop product, in a pretty heavy case for its size and is mains powered. Here they are together:


I say the minimalist look of Schiit products is best represented in this form factor. I also like the heft and feel of the large volume control.

The ifi is quite cute and nicely done from style point of view. Alas, I don't like switches spread everywhere on the side and bottom. Placement is more optimized though so perhaps that is good for...

Review and Measurements of Benchmark DAC1 USB DAC

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This is a review and detailed measurement of Benchmark DAC1 USB DAC. I recently reviewed the much newer Benchmark DAC3 which did very well. So question was posed how much progress has been made since the original DAC1. As luck would have it, someone brought a DAC1 USB over for me to measure at our latest Pacific Northwest Audiophile Society meeting.

From overall form factor and design language, not much has changed:

Benchmark DAC1 USB DAC Review and Measurement.jpg

It had maybe a little bit less polish than current units.

TIme was limited so this review will be short. Let's get into measurements and see how she did.

Let's start with our Dashboard view as usual:
Benchmark DAC1 USB DAC Dashboard Measurement.png

As you can see from the bottom text in green, all the measurements are for unbalanced analog output driven by AES balanced digital input. I think we tried USB but it was...

Review and Measurements of Sony MEX-XB120BT and Dual AM505BT Car Stereos

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This is a review and detailed comparison of two car head units: the Sony MEX-XB120BT and Dual AM505BT. Yes, you read that right: car stereos! I needed to replace the Pioneer car stereo in my boat with something that had bluetooth and much more power to play over the loud engine noise. I was pleasantly surprised to see both of these models sport much higher power/more efficient class-D amplification. This allowed me to get more volume without having to mess with an external amplifier.

The Sony MEX-XB120BT retails for $200 with Prime shipping on Amazon. The Dual costs more at $253, again with Prime shipping from Amazon.

Searching I was surprised to see that there is no measurements or detailed review of either unit. Specs are wild in car stereo and is hard to know what is real, and what is fantasy when it comes to power and such. So I decided to buy both from Amazon and return the one that didn't perform as well.

The Sony is a traditional CD player plus new formats such as...

Measurements of Klyne 7px 3.5 Phono Pre-amp

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This is a very brief measurement of Klyne 7px 3.5 Phono pre-amp. It is designed locally in washington state where I live and was brought to me for measurement at our local audiophile society meeting. It originally retailed for $2,500 and I think the owner said he bought it for $1,800. So not cheap.

Alas, I did not save much of the measurements other than one spectrum of 1 kHz. Before that, the unit looks pretty nice inside:

The unit came out in early 1990s so not available anymore (company doesn't seem to be building phono pre-amps anymore).

As noted, I did not save the rest of the measurements but the 1 kHz distortion and noise tells the story anyway:

Klyne 7px 3.5 phono preamp measurements.png

(please ignore the cursors). As we see, the noise from mains is highly dominant with the primary spike at 60 Hz just 40 dB down from our main tone. That causes a spray of...

Review and Measurements of Auralic Vega DAC

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This is a review and detailed measurements of the Auralic Vega DAC. From my quick search seems like this DAC was released sometime in 2013 but it is still current (about to be replaced?). It was brought to our local audiophile society meeting for me to measure so my time with it was very limited. As such, this review gets right to the point with measurements. Retail price as of this writing seems to be around $2,000 with the original cost of $3,500.

If you are not familiar with Auralic, they are a chinese company whose streamers are a fixture at audio shows. They have cornered the market for "high-end" audio streamers.

I have to say going into this review I just assumed this is an over-priced unit, surely with some faults. Read on to see if that came through.

As soon as I fired up the dashboard measurements, I knew my bias was incorrect:

Auralic Vega DAC dashboard measurement.png

113 dB SINAD (signal above power of noise+distortion)? This is near the top of any DAC...

Review and Measurements of Oppo UDP-205 UHD Player

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This is a review and detailed measurements of the Oppo UDP-205 UHD player's audio subsystem, specifically its DAC performance. It is on loan from a kind member. The retail price of UDP-205 used to be $1,300. Alas, Oppo has discontinued the unit so it is no longer for sale as a new unit. I see crazy prices like $4,000 now for them!

NOTE: My company is a dealer for Oppo. "Dealer" is a stretch of the term here as the discount for dealers will buy you a cup of tea and not the usual margins that exists for audio. But you should take this account in reading my review here.

There are probably hundreds of reviews of the Oppo UDP-205 out there. My focus here is only as a USB DAC to see how it compares to dedicated DACs. For this evaluation, I am testing its USB input and balanced analog outs. As a way of comparison, and as you see below, I also compared it to Schiit Yggdrasil DAC ($2,400), RME ADI-2 Pro (DAC version of which is $1,000), and Topping DX7s ($499)...
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