Articles, Reviews and Measurements of Audio Products

Review: Battle of Schiit Audio DACs

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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:

Schiit Modi Multibit Review Compared to Modi 3.jpg


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

Review and Measurements of Audirect Beam and AQ Dragonfly

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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:

Audirect Beam Portable DAC Review.jpg

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...

SMSL SU-8 Version 2 Balanced DAC

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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:
SMSL SU-8 DAC Version 2 Review.jpg

[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:
SMSL SU-8 DAC Version 2 Unbalanced Measurement.png


This...

Preview: Monolith by Monoprice Desktop THX Headphone Amp & DAC

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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:

Monoprice Monolith Desktop Headphone Amplifier and DAC Review.jpg


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...

Review and Measurements of Allo DigiOne RPI S/PDIF

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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.
Allo Digione Raspberry Pi SPDIF Output Jitter Review.jpg

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...

Tear down of Neurochrome HP-1 High Perf Headphone Amp

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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:

Neurochrome HP-1 Teardown PCB low res.jpg


For 4X higher resolution, click on this attachment:

Neurochrome HP-1 Teardown PCB med res.jpg

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...

Review and Measurements of Apogee Groove DAC and Amp

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This is a review and measurements of the Apogee Groove portable DAC and headphone amplifier. It is on kind loan from a forum member. As small portable DAC+Amps go, its retail price of $295 is quite high. I see factory refurbished ones at $149 though on Apogee website.

Apogee is best known for their professional audio products so their entry into personal audio is quite a departure for them.

As USB audio "thumb drive" form factors go, the Apogee is quite a bit more substantial:

Apogee Groove Portable DAC and Headphone Amplifier review.jpg


Volume wise, it is probably double the size of typical thumb drives. The larger size allows rubberized up/down volume buttons with excellent feel. There is no "plastic" feel to the unit either, making you think you can sit on it and nothing bad would happen to it.

The three LEDs roughly show the volume level. During music playback, they change to color to green and are fully analog. Each has individual intensity which once maxed out, lights up the one above it...

Tear down of Massdrop THX AAA 789 Headphone Amp

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With kind permission of the owner, I took apart the Massdrop THX AAA 789 headphone amplifier. If you have not seen it yet, check my my review of Massdrop THX 789.

The internal structure of this unit follows other models from Massdrop. I was impressed with the effort to keep all the components on one side using mostly SMT (surface mount) parts. The bottom of the PCB is only through-hole pins which I am assuming was wave soldered.

Here is lower resolution shot of the PCB with my annotations:

Massdrop THX AAA 789 teardown main PCB reduced2.jpg


Click on this attachment to get 4X higher resolution image.

Massdrop THX AAA 789 teardown main PCB reduced.jpg

I have 4X larger image yet again. Send me a message if you want that.

The biggest shock here is that there is no "THX module" of any sort! No custom or hybrid parts that I can see. Instead, we have a bunch of exclusively Texas Instruments parts...

Review and Measurements of Neurochrome HP-1 High-Performance Amp

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This is a review, detailed measurements and comparison of Neurochrome HP-1 high performance headphone amplifier to Massdrop THX AAA 789. It is on kind loan from company designer and owner, Tom Christiansen. I learned about Tom in chasing a review he had done of a passive volume control. I was very impressed with his depth of knowledge and thorough analysis using an Audio Precision analyzer. Tom is an analog designer, having worked for famous and large leaders in the industry (National Semiconductor and Texas Instrument). He is quite active in DIY audio forum, sharing his knowledge of engineering and audio. Needless to say, I was excited to get my hands on his products to test starting with his HP-1 headphone amplifier given its superlative measured specifications.

The HP-1 comes in all forms from bare PCB to fully populated board and finished package. I received the latter:

Neurochrome HP-1 Headphone Amplifier Review.jpg

The retail price for this version is $1,249. Bare...

Review and Measurements of Nobsound NS-DAC3 Pro DAC & Amp

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This is a review and measurements of Nobsound NS-DAC3 Pro DAC and headphone amplifier. It is on kind loan from a member. I see it on Amazon for USD $140 with free shipping from China.

This is the type of DAC you see in tons of Chinese websites with tempting features for the price. As you can imagine, there is nothing glamorous about such products. The packaging is as cheap as you can get. There is even a small CD with the drivers for your nostalgic feelings about computing days long gone. A couple of photocopied pages complete the picture as far as the manual is concerned.

The metal enclosure is not bad though and brings some uniqueness in this super crowded market:

Nobsound NS-DAC3 Pro DAC and Headphone Amplifier Review.jpg


As you can see, increasingly we see Bluetooth added to these small DACs. Also nice is dual headphone jacks.

In the back we have the usual S/PDIF, Toslink and USB inputs.

Anyway, let's see how she measures.

Measurements
Here is the dashboard view using the headphone jack...
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