Articles, Reviews and Measurements of Audio Products

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...

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: https://audiosciencereview.com/foru...sd-dac-and-portable-headphone-amplifier.3507/

The NX4 DSD retails for $160...

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.

Measurements
Let's start with our usual dashboard in high-gain mode:


Ah, just 1.5 volt output...

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:


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...

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:



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...

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:

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.

Measurement
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:



Long time readers of...

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:

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...

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:


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...

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.


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...

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: https://audiosciencereview.com/foru...measurements-of-schiit-yggdrasil-v2-dac.3607/

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...