Articles, Reviews and Measurements of Audio Products

This is a review, detailed measurements and comparison of Schiit Jotunheim Headphone Amplifier (with its optional Multibit DAC) and iFi micro 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...

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:



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.

Measurements
Let's start with our Dashboard view as usual:


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...

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...

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).

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



(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...

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.

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



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

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)...

This is a review and measurements of ELE EL-D02 ebay-special DAC and headphone amplifier. It is on kind loan from a member and the balance of budget DACs he has sent me. I see this unit selling on ebay for $16 including shipping.

From over build quality and feel, this is one of the most crusty, and cheap feeling DACs I have laid my hands on. It is light, and feels like there is nothing in there. An attempt at texturing the front and back panels results in even cheaper looking:



I suggest hiding it behind something if you care at all about your audiophile image!

Measurements
Unusually this DAC has both line out and headphone output with up/down volume controls no less. Let's start with our dashboard view of line out:



"Good news" is that nothing is badly broken. The displays were stable. Bad news is that 0.7 volts of output is quite anemic for line out (2 volts is more like it) so unlikely it is able to...

This is a Review and Measurement of Cheap Ebay CM108 Bare Board USB DAC. There are a number of these with the cheapest one retailing for just USD $8 (https://www.ebay.com/itm/CM108-TDA1...833370?hash=item467db6a85a:g:9hwAAOSwkJZbEbqj). It is part of a collection of USB dacs to test from a kind member.

Here is what it looks like:



The white solder mask saves the thing from looking crusty and cheap. Let's see how it measures.

Measurements
Starting with our dashboard we see this:


Distortion is about 100 times worse than the best products we test. Admittedly this is at max volume (but with 100 kohm load). Still, we are talking bottom of the barrel performance here.

Of note, the frequency counter was jumping up and down. Likely due to use of adaptive USB mode instead of async interface. FFT shows high noise floor and lots of...

This is a Review and Measurements of budget SMAKN X5 DAC and Headphone Amplifier. It is on kind loan from a forum member. It retails for just $25 on Amazon including prime shipping in US!

It is a cute little box with sturdy build:

It worked plug-and-play in Windows 10 Creators Edition so no driver install was necessary. I tested it using ASIO4ALL wrapper to create an ASIO driver for my Audio Precision APx555 analyzer in bit-exact mode.

Let's see how it measures.

Measurements
As you know, I always start with my Dashboard view and this is sort of what it looked like:


I say sort of because while the scope, output voltage and frequency were stable, the distortion figures were jumping all over, varying by as much as 20 dB! You can't see that in the static display so I put the analyzer in real-time mode and asked it to show the THD+N distortion figure as time marched on:

...

This is a detailed comparison, Review and Measurements of Sony PHA-1 and Teac HA-P50 Portable DAC and Headphone Amplifiers. They are on kind loan from forum member. The Sony retails for $250 and seems was released back in 2013. The Teac is likewise being sold on Amazon for $200. Both have that "cool" rack-mounted style albeit in tiny packaging. Here you see them on my Keysight/Agilent bench power supply for scale:



Between the two, the Sony feels more solid. On the test unit, the headphone jack on the teac is all but lose. It could barely hold the headphone jack. With owner's permission, I plan to open it up and see what is going on.

Both have high/low gain. I tested only the high gain.

Plug-and-play worked on Windows 10 Creators edition with no driver install for either unit. For my testing, I used ASIO4ALL virtual ASIO interface as that is the only one that my Audio Precision APx555 understands.

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