Sony Walkman NW-ZX2

Introduction

I recently attended a media event organised by Sony Singapore to introduce the NW-ZX2 - the latest flagship Walkman from Sony. Mr. Katsumasa Yoshioka, Senior Electrical Engineer flew down from Tokyo to present the product and to take questions from the attendees. Yoshioka-san was the leader of the electrical design team for the ZX2.

Technical Design

Yoshioka-san presenting the technical design of the NW-ZX2

The ZX2 was developed to co-exist with the ZX1 in the product line-up. Taking on user feedback, the design team sought to achieve a sound that was sharp yet not piercing, as well as being classy and smooth. To achieve this goal, the design team made improvements in the chassis, battery and audio components used.

The chassis improvements warrant some explanation. The ZX2 shares a similar aluminum alloy chassis to the ZX1. However, the ZX2 adds an internal copper housing, which is gold plated. Yoshioka-san explained that this was done to exploit the strengths of the various materials used, with aluminum offering a good balance of sound, and copper offering both good high and low frequencies, and a warmer sound. The copper housing is plated with gold to provide resistance to corrosion, as well as to provide a stable and low resistance ground plane.

The production of the ZX2 starts off with the solid aluminum alloy block as shown in the upper left corner of the picture.

A teardown of the ZX2

The new battery has a much larger capacity (1,860 mAh compared to 960 mAh for the ZX1) and an astounding rated 60 hour playback time with MP3 or 61 hours with standard resolution PCM / FLAC. 

High resolution playback brings down battery life to 16-43 hours of playback depending on sampling rate and file format (43 hours for 24/96 FLAC, and 16 hours for  5.6 MHz DSD) .

There is of course no free lunch, and the trade-off is low output, at 15mW (no impedance rating specified).

The circuit was also improved by thick copper PCB traces, multi-layer capacitors and additional Sanyo oscon capacitors (an increase over the ZX1 from 4 to 7 pieces).   

Separate ground wires for each channel (to reduce crosstalk between the channels) connect the audio board to the 4 pole output jack. Compatibility with 3 pole unbalanced connectors suggests that this is a non-balanced output. Fans of balanced drive will need to fork out extra for the PHA-3 DAC/headamp.

The ZX2 also gets two separate crystal clocks (44.1 kHz and 48 kHz) compared to the single clock used in the ZX1. The clocks are special low phase and noise parts.

Features

Features wise, the ZX2 comes fully loaded, with Bluetooth, Wireless-N wi-fi, and even a GPS receiver.

Internal memory capacity is 128GB, and a micro SD card slot allows memory expansion. File format compatibility includes MP3, WMA, AAC, FLAC, AIFF, WAV, ALAC and DSD (2.8 MHz and 5.6 MHz).

The 4 inch display has limited resolution by today's standards (854x480), but playing back the sample clip looked acceptable in quality to me. 

Feel and Operation

The ZX2 certainly feels like a flagship product. It has the necessary heft and build quality which is commensurate with it's price tag and product positioning. It is probably a bit too big and heavy to drop into your front shirt pocket though.

It was quite intuitive to operate, and anybody who has handled an Android based device should feel right at home. The recessed buttons on the side are not the easiest to operate though.

The PHA-3 DAC/headamp is able to tap the ZX2's digital output via Sony's proprietary WM-port slot located at the bottom of the unit.

I did not explore advanced features given time constraints.

Sound Quality

The ZX2 certainly sounded very detailed and spacious, with good bass impact. The high-resolution tracks uploaded on the demonstration units really showed off the ZX2 in a good light, and the sound quality on offer is very promising.

Some thoughts on the drive ability of the ZX2 - 15 mW is not an awful lot of current to play with. You will need to choose your partnering equipment carefully unless you pair the ZX2 with a headamp.

Driving the MDR-1ABT (24 ohms, 98 dB/mW) was perfectly adequate though. Coming to the MDR-Z7 (70 ohms, 102 dB/mW sensitivity), I was close to 80 % of the ZX2's maximum volume at my typical listening levels - you almost certainly need a headamp with the Z7.  

Quick Questions with Yoshioka-san

I took the opportunity to ask Yoshioka-san some questions about the ZX2. The first question related to DSD implementation in the ZX2. Yoshioka-san explained that the ZX2 did not handle DSD natively but converted it to PCM first. 

I also asked for his thoughts on the ZX2's drive ability. He suggested that a headamp be used for best results. 

I noticed that the presentation slides stated that the ZX1 used a single clock at 48 kHz. Yoshioka-san confirmed that the ZX1 upsampled standard redbook files from 44.1 to 48 kHz.

Parting Words

There has been quite a lot of online criticism against Sony over the pricing of the ZX2 (local RCP is S$ 1,599), which is substantially higher than the price of the ZX1. Understanding the design and improvements made by Sony's team gave me appreciation of the effort and thought that went into the ZX2. Hopefully, the opportunity will arise for an in-depth evaluation of the ZX2.

A note of thanks to Sony Singapore (in particular Mr. Leon Pereira) for inviting me to this event.

Plixir Elementa Power Cable

Introduction

Sound Affairs recently launched their in-house Plixir Elementa Power Cable. This is almost certainly a sign of things to come - Mr. James Soh, principal of Sound Affairs, hinted that a number of other cables are expected under the Plixir label.

Description

The Elementa is a supple and flexible cable which should minimise routing headaches. James advised that the Elementa is designed for low current applications, e.g. source equipment. It is also available in a variety of lengths and termination options. 

The review samples provided were terminated in Japanese Meikosha AC and Schurter IEC plugs. In use, they provided a firm and reassuring grip.

Sound Quality

The modest price tag is likely to appeal to audiophiles on starter systems, or with tight budget constraints.

In comparison to a stock power cord, bass notes took on a tighter, deeper and more articulate quality. Midrange was a bit laidback with a smooth and warm tone. Some subtle detail was lost there, but as a trade-off, this flattered sibilant and harsh recordings. Treble had a slight uplift, with increased clarity and separation. There was also a noticeable improvement in image definition and soundstage stability.


Conclusion

The Elementa power cable is a sensible and cost-effective upgrade, far exceeding my expectations. 

There are better power cords out in the market, but at much higher price brackets. The Elementa does a lot of things right and given the very reasonable price tag, this is definitely a winner.

Highly recommended.

Pricing

1 m    $89

1.5 m $119
2 m    $149  

Sound Affairs Pte Ltd

100 Beach Road, Shaw Tower
#02-34/35
Singapore 189702
http://mysoundaffairs.com

Sounds Affairs Plixir Balanced DC Power Supply and Balanced AC Power Conditioner

Introduction

Sound Affairs is a relatively new name in the local hi-fi scene, although it's principal, Mr. James Soh is a name familiar to many local audiophiles, especially for his previous work under the banner of Effective Audio Mod. 

Sound Affairs marks his move into a full-time retail business, with both sales and distribution of a complete range of hi-fi equipment, while continuing with modification work.

Sound Affairs offers a number of unique made-to-order products, including a DC power supply, and balanced AC power conditioner, which are the subject of this review.

I took the opportunity to ask James some questions about his approach to design in coming up with these products.

Design and Philosophy

James explained that that the Plixir Balanced DC Power Supply takes a unique approach. The custom wound transformer provides a balanced AC voltage supply (read on further for benefits of balanced AC power). Only two diodes are used for rectification instead of four. James believes that this is beneficial as all diodes create noise and distortion, so the less diodes used, the better. This topology, however requires the transformer to be double in power rating, increasing size and cost. The voltage regulation is done in two stages. The first regulation stage eliminates most of the voltage ripple, leaving an easier job for the second stage to handle. This also allows the heat to be distributed across both regulators, lowering temperature conditions. As a result, you get lower thermal noise and drift, better reliability etc. James mentioned that many single stage DC power supplies boast high attenuation of ripple at lower current, but as load current increases, the ripple increases as well. Only a two stage (or more) design can effectively solve this issue to ensure a low noise power supply to the load at high current.

Other design features include high speed, fast recovery diodes, and used of snubbers across these diodes.

Coming to AC power conditioning, I asked James on his views on balanced AC power versus other methods, e.g. noise filtering using capacitors, chokes or power regeneration. He drew parallels between the use of his balanced transformer to the output transformer of a tube amplifier. A tube amplifier output transformer couples the high impedance of the power tubes to present a low output impedance on the amplifier's output. Similarly, his  balanced transformer is designed to couple the high impedance of the power line to present a low output impedance source of AC power. He mentioned that balanced power is commonly used in professional audio to resolve ground loop and noise issues. The transformer used in his Balanced AC Power Conditioner is also lossy at high frequencies, while being efficient at the 50 Hz mains frequency used locally. This helps to filter out high frequency pollution on the mains line.

In comparison, James felt that mains filtration using capacitors is a hit-and-miss affair, as there is guesswork involved in the effective range of the filters. Further, the choice of capacitor influences the tone of the system. As for inductors, his view was that these limit current and adversely affect impedance by adding resistance, and distort the AC wave form.

James acknowledged that power regeneration has many benefits but had reservations on the transient speed and dynamics. The AC/DC/AC conversion was to him an unnecessarily complicated approach. The "speed" of DC supply was also a question mark, as the chemical conversion to electricity (whether through the discharge of capacitors, or drawing from a battery supply) may not be quick enough to cope with fast fluctuations in current demand. Long term reliability is also impacted by heat and the complexity of the design.

Plixir Balanced DC Power Supply

The Plixir Balanced DC Power Supply is a compact power supply housed in a simple but smartly finished aluminum box. The rear panel contains the IEC inlet, a fuse holder, the power switch, and a socket for the detachable DC lead. The supplied lead is of high quality and comes with a locking collar.

In operation, it runs cool to the touch even when left on permanently. 

I purchased a 15 V DC model to power my Auralic Aries. Prior to that, I was using another well regarded linear power supply, which sounded better than the stock switched mode power supply,  but too dark and lacking in air for my taste. 

The Plixir was noticeably superior in all aspects, sounding more open, faster, while retaining a solid bass foundation and quiet background. Unlike most upgrades that involve some kind of trade-off, this was an all round improvement and easy to recommend. 

Plixir Balanced AC Power Conditioner

Plixir BAC 800

I was provided two different models for purpose of this review, a BAC 150 and BAC 800 (the model number denotes the rating of the conditioner in watts). 

A number of build options are offered, including upgraded AC outlets, UPOCC internal wiring and Bybee Quantum Purifiers. The units I tested were stock models, which were supplied with high quality Meikosha outlets from Japan.

Similar to the DC power supply, both units ran cool (neither were loaded beyond 50 % of their maximum rating throughout my period of review).

A number of combinations were tried in both of my setups.

1. BAC 150 with source equipment in my main listening room

I tried the BAC 150 first with an Audio-Gd NFB-10ES2 headamp / DAC and also my Cary CD-500, which are in my main listetning room. The power quality there is the highest and most of the audio equipment do not share power lines with noisy household appliances and the like.

Bass quality improved with a nice increase in heft and slam. There was also a noticeable reduction in the noise floor, and the enhancement of detail. The midrange took on a smoother and more laidback feel. I felt that this came at the expense of a darker tonality and a slight reduction of "air".

I did not try my amplifiers with the BAC 800 as their current draw exceed the unit's rating.

2. BAC 800 with Antelope Zodiac Platinum and Job 225

My bedroom setup is less fortunate. It sits on the same line with a whole range of things, including a Plasma TV set, a cable set top box, alarm clock and a computer. 

First, I tried the much bigger BAC 800, with both my source and amplifier plugged into the conditioner. 

Interestingly, I did not notice any mellowness, or reduction in "air" here. I would think that most people would be suitably impressed with this combination. 

Bass was tighter, more extended, and dynamic. You could really feel the added extension, drive and energy of bass lines.

Soundstaging also improved in depth, while there was improvement in detail, separation and refinement. This was most noticeable on heavy mixes, where the additional coherence and detail retrieval allowed you to follow the separate instrument lines clearly. 

3. BAC 800 with Antelope Zodiac Platinum

I also tried hooking up just my source to the BAC 800, with the Job 225 plugged directly into the wall.

The reason I tried this was to see whether the conditioner was restricting current to the power amplifier. This did not seem to be the case here.I actually thought that this sounded worse compared to having both my source and the Job 225 plugged into the BAC 800.

4. BAC 150 with Antelope Zodiac Platinum, and BAC 800 with Job 225

James had in fact suggested that I try out using two separate conditioners,and had supplied me with two sets for this purpose. 

While the system tonality was similar to just using the BAC 800 alone, there was significant improvement in soundstaging, high frequency extension, low level resolution, and a modest improvement in all the other audiophile niceties observed earlier.

I happened to be listening to a live recording, and you could really feel the acoustic space of the venue, and the reverb from the vocalist and accompanying instruments. 

In fact, I would rate the step-up in improvement moving from one to two balanced power supplies to be on par with the improvement going from stock to a single balanced power supply. I had no reservations using this combination and it was nice to be able to have your cake and eat it too !

Conclusion

I was very pleased with the performance of both products. The DC Power Supply makes an excellent alternative to the multitude of other power supplies out on the market, and the ability to work with someone locally to provide custom options is a boon.

While the benefits of the Balanced AC Power Conditioner is more dependent on the quality of your mains power supply, I was suitably impressed with the BAC 800, and even more impressed using the BAC 800 in combination with the BAC 150.

The Plixir line impressed me with it's good build quality, reasonable pricing and outstanding performance. Highly recommended.

I would like to thank James Soh of Sound Affairs Pte Ltd for his time in answering my questions and for supplying the review units.

Specifications and Price

Plixir Balanced DC Power Supply

Specifications and dimensions vary with voltage and maximum current.
Price - S$ 449 upwards

Plixir BAC 150 Balanced AC Power Conditioner 

150 watts
Two outlets
Weight - 4 kg
Dimensions - 220 mm x 50 mm x 225 mm
Price - S$ 450


Plixir BAC 800 Balanced AC Power Conditioner

800 watts
Four outlets
Weight - 9 kg
Dimensions - 144 mm x 155 mm x 250 mm

Price - S$ 1,190

Sound Affairs Pte Ltd
100 Beach Road, Shaw Tower
#02-34/35
Singapore 189702
http://mysoundaffairs.com