Articles, Reviews and Measurements of Audio Products

This is a detail measurements of the iconic, Nakamichi Dragon Vintage cassette deck. It was kindly brought to me at a meet at our local audio store (Gig Harbor audio).

For those of you too young to know , the Nakamichi Dragon has the reputation of being the best cassette deck available at the end of the cycle for the format. It came out in 1982 and retailed for USD $2,499. That would be $6,500 today's dollar so quite a lot of money. I was too poor to afford one at the time so it was a pleasure to get my hands on one finally for this test.

We were testing it in a dark room and this is just with the light of a phone so please forgive the poor lighting:


Unlike digital products and amplifiers, we are at the mercy of calibration tapes for testing such products. The owner had a few of them and that is what I used for testing.

I unfortunately did not capture the results...

This is a review and detailed measurements of Audeze Deckard DAC and headphone amplifier. It is on kind loan from a member and seems to be discontinued. Seems to be a product of year 2016 with retail price of USD $699. Owner has bought it used for much less.

The unit has rather unusual hefty metal enclosure with super sharp extruded aluminum edges that can easily pierce your fingers:


Other than that, the volume control feels very nice. There are RCA outputs and inputs in the back. The RCA out is variable and seems to just be connected to the output of the headphone amplifier. I only tested the unit as a DAC+Amp combo. With the front toggle switch, seems like you can use it as just a headphone amp/pre-amp if you wanted.

Looking for information on it, I ran into a CNET review saying this:



Is Steve Guttenberg right? Let's find out!

Measurements
I adjusted the output to typical 2 volt...

This is a review, detailed measurements and comparison of Apple's USB-C adapter to the current and last version of Google Pixel headphone adapters. The Apple adapter costs just $9 including one day shipping for free. The Google dongle costs $12.

Not that any of these are large by any stretch but Apple's is also the smallest of the three:


Oddly there is no apple logo or markings on the device. The others don't have it either but I thought Apple would insist on that.

All three adapters work in Windows with the appropriate adapter and that is how I tested them, allowing my analyzer to fully control and quantify their performance.

Format wise, Apple's supports the key ones:


So very similar to Google Pixel V2 and better than V1 which only supported 48 kHz.

Note that volume control in Windows is active at all times even if you use WASAPI exclusive mode!

Not much else to talk about than getting into...

This is an analysis of whether you are better off using low or high gain mode in a headphone amplifier in their overlapped region. Traditional rule of electronic design says there is no free lunch: higher gain means higher noise. While this has become the "conventional wisdom" and one that I routinely state myself, forum member asked if there is any hard data to back this. So I decided to test the theory on two headphone amplifiers: the Schiit Magni 3 and JDS Labs Atom.

The test matrix here is infinite in scope. What volume does one choose for each gain to test? After pondering for a second or two , I decided to go the defensible route of setting low gain to max and then matching the same in high gain. Both of these amplifiers have analog volume controls and in high gain, they can be touchy as far as getting accurate levels out of them but I managed to get close enough.

Let's see what the measurements say.

Measurements...

This is a review, detailed measurement and comparison of Schiit's Modi 2 (uber), Modi 2 Multibit and Modi 3. I have reviewed the Modi 2 uber and Modi 3 before so this is mostly focused on how the Modi Multibit compares to them. I have purchased all of them personally at different times. The Modi 2 Uber is now replaced by Modi 3 with the latter costing USD $99 plus shipping. The Schiit Multibit fetches quite a premium compared to that to the tune of USD $249 plus shipping. Is the extra cost worth it? This is what this review is about.

Starting from the top, Schiit seems to be playing with its design in each one of these units:



Switch type, color and finish seem to vary some...

This is a review, measurement, and detailed comparison of two "thumb drive" sized combo DAC and headphone amplifiers: the Audirect Beam and Audioquest Dragonfly Black. I had reviewed the latter last year but it was with my old measurement gear so I thought I perform a fresh set of data on it given the popularity of Dragonfly. I purchased the Audirect Beam from Amazon a few months ago for USD $104 (about $114 with tax). I purchased the AQ Dragonfly for USD $99 from Amazon just the same. The Audirect Beam is on sale for $80 on massdrop and hence the reason I thought I review it now just in case you want to take advantage of its sale.

The Audirect Beam is the smallest DAC+amp I have seen, sans the phone USB-C dongles:


It has a spring-loaded, nice feeling momentary rocker switch for turning the volume up or down. Sadly in practice it would not change level correctly, requiring multiple toggles.

The volume control changed the...

This is an update to my previous review of SMSL SU-8. At a retail price of USD $212 on Amazon and balanced outputs, the SU-8 could provide a very compelling proposition. Unfortunately the performance of the balanced output in my first review sample was disappointing, showing significant switching noise. SMSL was kind enough to send me a second unit recently and I put it to test.

There is no functionality difference so see the previous review for details of that. Briefly here, you get a nice looking unit with a tiny display and remote control:

[the 44.1 kHz on the display is not showing all the way due to my camera shutter not being in sync with its refresh rate.]

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

Measurements
Let's start with our unbalanced dashboard:


This...

This is an early look of the Monolith by Monoprice Desktop Headphone Amplifier and DAC with THX amplification technology. The unit was kindly purchased by a forum member and drop shipped to me. And that is where the trouble began but more on that later. The Monoprice THX amp and DAC retails for USD $480.

The Monoprice THX amp and DAC has the same design language of other "monolith" units which translates to a serious look. There is brushed metal on front and very shiny and glossy enclosure which instantly shows fingerprints:



Let's backtrack a bit. I have ordered three products from monoprice. The first one never came and I only found out about it a few months later. I then ordered two other products from them both of which were sent to a remote neighbor. Their street and house number are one digit off from us. Hard to imagine how someone could be this bad at reading addresses yet be in delivery business.

Worried that this unit would also...

This is a review and detailed measurements of the Allo DigiOne Raspberry Pi digital audio (S/PDIF) interface. It retails for USD $99 and is on kind loan from Allo. Unlike its higher-end brother (DigiOne Signature), this is a single board implementation at half the price.

When combined with a Raspberry Pi, and a suitable "audio operating system" (e.g. Volumio used in this review), you have a $135 networked S/PDIF interface. Hook the output of this board to your favorite DAC and you automatically add networking to it, allowing you to place the computer server elsewhere and stream content to your audio system.

Testing digital audio outputs is quite different than our typical analog measurements. Here, we are interested in how pure the digital output is as to produce good performance out of any DAC regardless of how good its S/PDIF interface is. I took a shot at this when...

This is a tear down of the Neurochrome HP-1 High performance Headphone amplifier. My review of HP-1 showed exemplary distortion and high power handling. With kind permission from its designer, here is a look at what is inside.

Here is a lower resolution shot of the PC board:



For 4X higher resolution, click on this attachment:



You may have seen my tear down of massdrop THX AAA 789 amplifier which had plenty of empty space. Not so here. As you see, nearly every inch of space is used.

Unlike the massdrop THX 789, the power supplies for the HP-1 are internal. We have two switching supplies from the reputable Mean Well Taiwanese company. I am assuming one...