Articles, Reviews and Measurements of Audio Products

This is a review and detailed measurements of the Musiland MU2 portable USB-C DAC and Headphone amplifier to be used with modern phones without headphone jacks. It is on kind loan from a member. It costs US $85 which is on the high side of what these costs.

I previously measured the Musiland MU2 Plus and this looks identical to it:


It looks slick and much better than the tiny dongles we normally see for $9 or so. You have up and down volume buttons. I thought "M" stood for Mute but it actually cycles through three different output levels. I only tested it at the highest level.

Let's get into measurements to see how it does.

Audio Measurements
As usual we start with out dashboard at 1 kHz:



The output level is 1.4 volts which is below nominal value I like to see for DAC...

This is a review and detailed measurements of the JDS Labs Element II DAC and headphone amplifier. It was kindly sent to me by JDS Labs. The Element II costs US $399 and is a marriage of the JDS EL DAC II ($299) and EL AMP II ($249). So you save good amount of money by purchasing the combination.

From the outside, the Element II looks just like the EL AMP II which is a good thing:


The same marquee volume control adorns the Element II as it did with EL AMP II. The back side is a combo of the two products:


You lose the coax and s/pdif digital inputs which the EL DAC II has.

The gain button does what you imagine. The power button has double function where you hold it...

As promised in my review of the Nord Three SE 1ET400A Dual Mono amplifier, here is a tear down of its construction. Since the individual modules are known quantity, I didn't try to take close up pictures of them. Instead, my focus is on the overall assembly of the unit:



From high level, assembly seems neat and tidy. I checked the grounding and was pleased to see that anodization coating was properly removed and nice ground lug attached to it.

I was also pleased to see custom length power supply to power amp wiring harness. The one closer to the amp has a shorter lead which is nice. This however does point out the asymmetry in design. The top amp has to have a longer power lead and over that drapes over the amp. Two independent boxes would be superior in this regard. We can see the same lack of symmetry in the way...

This is a review and detailed measurements of the ATI AT522NC Stereo power amplifier. It is on kind loan from a member. The 522NC costs US $2,195 but I see it on Amazon for US $1,995. The AT522NC is part of a series which starts with 2 channels of class D amplification and goes up to 4 channels in the same enclosure.

The industrial design of the AT522NC has some unique touches, some of which work, some that don't:

The part that detracts is ironically the ATI logo.

The power button has a very nice feel and gives one impression of quality.

Looking at the back, I was surprised by choice of input power connection:


It is a 20 amp IEC connection rather than the most common, 15 amp variety. This is partially due to use of linear power supply and massive/heavy toroidal transformer. But the most common reason is that the same setup is used in higher channel count amplification.

The...

This is a review and detailed measurements of the JDS Labs EL AMP II Headphone Amplifier. It was kindly supplied to me by the company and is the companion to the EL DAC II I just reviewed. The EL AMP II costs US $249. JDS previously set a record with the Atom headphone amp which produced superlative performance for just US $99. Many people have asked for that performance but in a metal enclosure. Is the EL AMP II the answer? We will find out.

The EL AMP II uses the sexy enclosure of previous generation product with its massive volume control:


As you see, it stacks nicely on top of the EL DAC II.

All controls are in the back:


The power button plays double duty controlling whether the headphone or line out is active. I limited my testing to headphone out.

The gain switch toggles...

This is a review and detailed measurements of the JDS Labs EL DAC II USB DAC. Company asked me if I want to wait to get a unit from customers or a sample from them. In the interest of timely disclosure of its performance, I opted for the late option. The EL DAC II costs US $299.

The EL DAC II enclosure is made out of metal and looks slick:


The front control both powers the unit and cycles through the three separate inputs. There are no other controls making the unit easy to use, albeit, with possibly less functionality.

The rear of the unit shows the typical connectors:

The usual large, AC transformer that JDS ships universally for all of their products is needed to power the EL DAC II.

As noted, it is very comforting to know that the product has met both US and European safety and emissions standards. To often audiophiles worry about "EMI/RF radiation" only to buy products that are...

The Behringer ULTRA-DI DI20 is a cheap DI Box. DI boxes are usually used on stage to convert an unbalanced source into a balanced source for transmission over longer distances, e.g. from a keyboard to the FOH mixing console:

• use a short unbalanced cable between the keyboard and the DI box
• use a long balanced cable between the DI box and the mixing console.

DI boxes also offer a ground lift switch to break a ground loop which may induce hum into the system. Therefore you can use them also in a stereo or HT system if there is a problem with ground loops or hum, e.g. when a satellite receiver is connected to the amplifier.

DI boxes come in two flavours:

• passive - using an audio transformer. They can handle large voltage differences due to galvanic decoupling.
• active - using an amplifier with balanced output. Power is supplied by 48 V phantom...

This is a review and detailed measurements of the Nord Three SE 1ET400A Dual Mono Stereo Amp with the optional Sonic Imagery 990Enh gain stage. With that option, the cost is £1,979.00 excluding VAT. This translates into US $2,554. The unit was purchased new and drop shipped to me by a kind member. I had previously measured the reference design from Purifi so will be good to see how this version rates with a different input stage.

The Nord dual monoblock comes in a very attractive enclosure (most of which is not visible in this image):


Efficiency of class D amplifiers and switchmode power supply enables such slim case to be used. There are two rows of heatsinks on the sides but they are decorative for the most part. I will do a teardown separately. For now, the amplifiers dissipate heat into the...

This is a review and detailed measurement of the Android basaed HiBy R6 Pro Portable Digital Audio Player (DAP). It was kindly loaned to me from an overseas member. The R6 Pro costs US $549 from Hiby's own store.

Any resemblance to a modern mobile phone ends with the Android OS. The R6 Pro is very heavy, thick and chunky compared to any mobile phone:


One advantage over any mobile phone is hard switches for standard transport control (play, pause, etc.). Another advantage is ability to act like a DAC over its USB-C port and a Coax digital input.

Personally I think Android brings way too much software for just a music player. Changing the language from Chinese to English for example required digging deep in settings to do (thanks to members who helped me do this).

While I did not play with the unit much, the touchscreen was quite responsive. The display looks dull but this could be due to settings for it.

For my testing, I...

This is a review and detailed measurements of the ifi Zen balanced DAC and headphone amplifier. I purchased it from Amazon last week. The Zen DAC costs US $130 including free shipping.

I must say, I am not a fan of the look of the Zen DAC. It hearkens back to 1960s furniture style which would look out of place on most desktops:


Despite commonality of aluminum in audio products today, the Zen must be using some kind of steel for its shell as it is quite heavy for its size. And sturdy to boot.

The controls are confusing. "Power Match" seems to just be extra gain/power and nothing to do with ifi's "IEMatch" products which lower output volume. Despite having plenty of space on the front, the "balanced" headphone output is 4.4mm jack which is much more rare. These guys have made such a mess out of this business of "balanced" headphones with so many connectors. I had to pay $25 to buy an XLR to 4.4mm adapter as I could hardly find...