The Well-Tempered Computer, an introduction to computer audio

Friday, December 31, 2010

Calyx DAC 24/192

Calyx Audio of South Korea will launch launched its minimalist 24/192 DAC at the upcoming CES2011.  Specs looks very promising indeed.

  • Asynchronous USB 2.0
  • 24-bit/192kHz capable via USB (Drivers in Windows, Native Mac OSX 10.6.4 and above)
  • 32-bit/192kHz capable via S/PDIF
  • 8 x ESS SABRE ES9018 32-bit DAC chip per channel (Total of 16!!)
  • Two word clock generators, one for 44.1/88.2/176.4, another for 48/96/192 kHz
  • Selectable power from USB or 5v DC via back panel rocker switch
  • USB or Coaxial SPDIF via back panel rocker switch
  • Aluminum monocoque chassis
  • Two sets of analog output RCA and balanced XLR
  • THD of 0.00005%
  • 123dB signal to noise ratio
  • Output voltage RCA 2.2v, XLR 6.6v (higher than average even with 5v input voltage, that's what the parallel DAC chips can do)
  • 220 x 220 x 45 mm
  • 4.4kg
  • US$1,500
I'll be getting a sample for review in the next two weeks or so. 

Oppo BDP-95 Universal 3D Blu-ray disc player

Shipping in February 2011 is the Blu-ray player to rule them all. The BDP-95 is Oppo's replacement of the acclaimed BDP-83SE.  The BDP-95 shares the same drive mechanism as its sister BDP-93 but with optimized analog audio performance.

  • 2 x ES9018 SABRE 32-bit reference DAC chip, one for 7.1 output, the other for stereo
  • Dynamic range of up to 135dB
  • Rotel-made Toroidal linear power supply (major upgrade from the BDP-83)
  • Dedicated stereo outputs, RCA and XLR
  • Coaxial and toslink digital outputs
  • Dolby TrueHD and DTS-HD
  • Plays every disc known to man including Blu-ray 3D , DVD-Audio, and SACD 
  • Netflix and Blockbuster streaming
  • Qdeo technology video processing provide DVD upconversion to 1080p
  • True 24p pull-down
  • 2 x HDMI 1.4a
  • 2 x USB ports
  • Wireless and Ethernet
If that still does not satisfy you, Nuforce will announce announced at CES2011 three modified versions, the BDP-93NE (Nuforce Edition), the BDP-93NXE (Nuforce Extreme Edition) and the BDP-95NXE. 

Network music streamers

If you want to stream digital audio files on your computer to your stereo hi-fi set, you have quite a number of options.  Here are some of them.

Apple Airport Express

A small 802.11n hub/base station that plugs direct into your wall socket.  Not only it is able to create and connects up to 10 users and share a USB printer over wifi, it allows you to stream iTunes over wifi from your computer (the toggle on the lower right hand corner in your iTunes window selects computer or the AE), the Airport Express is then connects to your stereo system over an analog mini output, or a digital mini-toslink output.
  • Small, easy to set up
  • Works only with iTunes's "Airplay" protocol
  • Convertible mini jack analog/digital toslink output
  • Support AIFF, WAV, ALAC, MP3, and WMA files
  • Only compatible with 16-bit/44.1kHz and 48kHz files
  • $US99
The Airport Express works very well.  The analog output sounds surprisingly good considering the diminutive size (putting switching power supply together with DAC and everything else is certainly not a good thing).  if you use normal cable, the toslink output requires an mini-toslink adapter, and it plugs into the same hole as the analog mini output.  My quibble is that having a toslink multiplexer in the digital audio stream is jitter-prone and would like to see a coaxial RCA digital output.  However, since electrical isolation may be a challenge given its small form factor, Apple's engineer may have chosen toslink which is electronically isolated.  Now if you want a better case and power supply...

The WM-10 is basically a souped-up Airport Express but they call it "Airstream".  It has basically the same specs and functions except the aluminum case (black or silver) and better power supply (R-core transformers rather than switching PSU).  Although it uses the Cirrus Logic 4344 24-bit/192hKz DAC (same with the AE), the streaming is limited to 16-bit 44.1/48kHz files due to Airplay limitations.  Another limitations is that no matter what file you choose to play, the WM-10 will convert to Apple Lossless (ALAC) on the fly (same as the AE).  Although Micromega is a great french digital company with experience in this field, I still do not see the point of spending $1,595 vs Airport Express' $99.  

Micromega also makes an integrated amplifier with Airstream built-in, the AS400.  Denon and Marantz are coming out with their own version of Airplay compatible network streamers.  Watch this space.

Linn of UK went all out and announced that they will no longer produce CD players and will only market digital streamers, or "DS" in Linn lingo.  Linn DS players music stored on a hard-disk or Network Attached Storage through RJ-45 Ethernet (Linn doesn't believe in Wifi).  There are 3 models, from expensive to super expensive:
  • Majik DS - Plays FLAC, WAV, MP3, AIFF with resolution up to 24/192kHz, Ethernet input, on-board digital volume control.  No digital output.  There's also an integrated control+amp model called Majik DS-i
  • Akurate DS (above) - adds WMA, OGG and AAC support.  Adds balanced XLR analog audio and digital (BNC S/PDIF) output.  Linn Dynamik switch mode power supply.
  • Klimax DS (below) - pretty much the same guts as the Akurate but with better chassis, power supply and analog output stage.

Logitech Squeezebox Touch
For those who do not want to be stuck with everything iTunes and the constrictive 16-bit.  The Touch is the latest incarnation of the successful Squeezebox series.  It is a great product and will play any file format you throw at it up to 24/96 resolution.  It is compatible with both Windows and Mac, iTunes and others.  You need to install a small host program called Squeezebox Server in your host computer and the squeezebox will find the music library automatically when connected to the same wifi network.  The touch screen works well and easy to read.  There was never a single drop-out over the 3 months I used it.  Software on the unit may not be as robust and as user friendly as the Apple-designed ones, but it works as advertised.
  • 4.3" touch color screen
  • Wifi 802.11N, or Ethernet connection
  • AKM4420 DAC chip (one of the best "mid-fi" chip there is)
  • USB host port for external USB drives - can be hacked to make it work with USB DACs
  • SD card slot 
  • Play virtually all formats
  • Built-in internet radio capabilities
  • Abilities to add custom "apps"
  • Coaxial and toslink digital output
  • 24-bit/96kHz compatible
  • US$299
You can control the Touch using it touchscreen interface, its included small black remote control, or the excellent iPeng app for iPhone and iPad.

The Touch sounds good.  Very easy on the ears and on the soft side and has a laid-back presentation, it is quite good out of the box with little or no break-in.  However we audiophiles are never satisfied.  After searches on the internet, I found out that there are modification services specifically for the Touch available from specialist companies like Audiocom and Bolder cables.

I went for the Audiocom Level-2 digital upgrade (GBP277), sending the unit to UK where they install Bybee slipstream purifier for DC input and replaces circuits with low noise wide band regulators, OS-CONs everywhere and replaces the coaxial digital output circuit with silver wiring plus a nice NextGen digital output jack from WBT.  

I also purchased the Teddy Pardo's TTouch Power Supply (EUR270) which replaces the 5v switch mode wall wart with the superiorly low-noise power supply featuring the propreitary SuperTeddyRegulator.  

Sonic improvements after the upgrade are apparent.  The sound is now cleaner, more articulate and refined.  However, I am using it to feed an external DAC that I am familiar with.  Let me tell you this, as a transport, It beats all the disc-based transports I own and it is definitely better than running toslink direct out of the Mac mini.  Perhaps Wifi protocol just re-arranges the bits and eliminates jitter.  May be the power supply is so clean that the background becomes blacker than black.  The Audiocom modded Squeezebox Touch with Teddy Pardo PSU is the absolute best sounding transport I have ever own. 

Thursday, December 30, 2010

Bryston BDP-1 Digital Music Player

Designed as a companion to Bryston's well-respected BDA-1 DAC, the BDP-1 is a high resolution digital audio player with no DAC of its own.  Sort of like a disc-less transport.  Takes in digital audio data from its USB port, so your music stored in a USB hard drive and thumb drive would work.  the BDP-1 can also connects to a NAS drive on a network through an ethernet connection. Sorry no wifi at the moment.  The Linux-based machine connects to an external DAC via SPDIF outputs.  

  • Connects to external USB drive (one thumb drive included)
  • 4 x USB ports (2 front, 2 back)
  • 16-bit and 24-bit compatible
  • 44.1kHz to 192kHz and everything in between
  • Fanless, Linux based
  • AIFF, FLAC and WAV compatible
  • 1 x AES/EBU and 1 x BNC SPDIF outputs
  • Galvanic isolation of inputs
  • Controllable through a soon-to-be-released iPod/iPhone app
Well, at US$2,100 and no Wifi?  It must sound really really good to win people over from Windows or Mac based solutions, let alone a squeezebox touch's excellent digital output over wifi.  Or if you want to go overboard with the Mac, there is always the Mach2Music (a modified MacMini with Solid State Drive for $1,495).

Soulution 540 "entry" level CD/SACD player processor

Soulution of Switzerland will announce its entry-level CD/SACD player at CES2011 on January 6th.  When Soulution says "entry", it's still $30,000 (whew!).  Soulution's amplifiers are the new The Absolute Sound's darling.  I can only tell from a recent local dealer launch of the 540's bigger brothers, the 745, it is absolutely gorgeous!

  • Teac Esoteric UMK-5 (VRDS neo) transport mechanism
  • Plays CDs and SACDs
  • Up-sampling to 24/192kHz
  • Digital inputs and outputs (AES/EBU, Coaxial, Toslink)
  • USB input (24/96 only)
  • Balanced and RCA analog output
  • Dual discrete current to voltage converters per channel
  • Digital volume control

Great softwares from Rogue Amoeba

Great collection of softwares (mostly for Mac) from Rogue Amoeba.  Everything is free to try with some features disabled.  All of them is $25-$32 to buy.

Airfoil (For Mac and Windows): Play any audio across your network to a whole host of devices, all in sync! Airfoil sends audio to remote speakers including iOS devices, other computers, and hardware devices like the Apple TV and AirPort Express. Airfoil for Mac gives you any audio, everywhere.

Audio Hijack Pro: Record any audio - three simple words to explain Audio Hijack Pro. Record from applications like iTunes, Skype or DVD Player. Record from microphones, Radiosharks and other hardware. If you hear it, you can record it.

Pulsar:  XM and SIRIUS both provide online access to most of their stations, but tuning in with a browser is clunky at best. With Pulsar and an XM or SIRIUS online account, you can access all this great content directly from your desktop!

Radioshift!: With Radioshift, you can listen to and record internet and AM/FM radio from around the world on your schedule.
Nicecast: The easiest way to broadcast music from OS X. Broadcast to the world, or just across your house. Nicecast can help you create your own internet radio station or allow you to listen to your iTunes Music Library from anywhere in the world

Fission: Streamlined audio editing, you can quickly copy, paste and trim audio, as well as split files. Fission also works with compressed MP3 and AAC formats to edit without the quality loss caused by other editors. Get perfect quality audio when editing natively in the MP3, AAC, Apple Lossless, AIFF and WAV formats.

Rasteme RUA220 USB DAC and Amplifier

Came across an interesting USB DAC+Amp out of a Japan-based company, Rasteme.

RUA220: Compact, USB-only DAC, with a 20W (4ohm) stereo integrated amplifier and a separate headphone output.
  • Asynchronous USB 2.0 protocol
  • 24-bit / 192kHz (with custom Windows ASIO/WASAPI and Mac drivers)
  • Low jitter, high precision clock (2ppm crystal oscillators)
  • 96dpi color OLED display (can even display photo uploaded from a mini USB input)
  • Capacitor-less headphone output (max 80 mW)
  • Digital volume control
  • S/N ratio of 100dB
Only available in Japan at the moment for Yen 56,700 (around US$700)

Rasteme also makes other interesting products including the higher-end UDAC192 (32bit, WIMA capacitors, Toroidal transformers, Clock input, SPDIF, Balance output) and the RUDD14 USB to SPDIF converter (Asynchronous, 24/192, galvanic isolation, 1ppm TCXO, and full range of SPDIF outputs, Yen 57,600)

Tuesday, December 28, 2010

Cypher Labs' AlgoRhytm Solo iDevice digital audio processor

Yet another new iPod digital audio DAC/Transport with digital output.  The battery-powered AlgoRhythm™ Solo is a digital audio processor for Apple iPad, iPhone, or iPod devices.  The digital audio is accessed asynchronously via USB port then routed to the reference grade Wolfson Microelectronics DAC.  

  • USB interface works with iPad, iPhone and iPod (won't work with computer USB output)
  • 1/8" analog line out
  • Simultaneous S/PDIF coaxial digital output 
  • Lithium-ion batteries
  • 10 configurable timers and 3 clock chips allow maximum flexibility in controlling timing, resulting in ultra-low jitter (err...whatever that means)
  • AC adapter for charging batteries

Monday, December 27, 2010

Unity Audio "The Rock" Active Monitor

Searching for the world best small active monitor, I came across an interesting product from UK's Unity Audio.  The Rock is available in two version, Pro audio and Hi-fi, with the Hi-fi version slightly nicer looking with black gloss finish.  It's a sealed-box design with internal amplifier module designed by E.A.R's Tim De Paravicini. 

Front baffle is Corian bonded to plywood cabinet.  Corian is a very dense, stone like material, this improves the rigidity of the baffle.  Folded ribbon tweeter and 7" pulp fiber woofer are from Germany's ELAC.  The ribbon tweeter's is flat to 50kHz, great for high resolution music.  Internal wires are cryogenically treated.  Internal amplifier is 100 watt discrete bi-polar low feedback with separate transformers for each drive unit with no crossover networks (30 watt to the tweeter and 70 watt to the woofer).  Sealed box meaning placement would not affect bass performance as in other open-box ported designs.

  • 2 way active monitor
  • Bespoke true class A/B 100 watt E.A.R. discrete amplfier
  • Closed cabinet design
  • Corian front baffle, highly polished black finish
  • Graded and matched components
  • 2.5mm OFC VDC cyrogenic speaker hook-up cable
  • 50kHz folded ribbon tweeter
  • 7''/180mm woofer
  • Balanced XLR input, or
  • Un-balanced RCA gold plated phono input
  • Piano black high gloss finished Baltic birch 9 ply plywood cabinet
  • 11.2kg each
  • 290mm x 220mm x 325mm 
  • Approx $1,000 for EACH speaker (so $2,000 for stereo pair)

Devialet D-Premier DAC+integrated amplifier

Once in a while something very fresh and original came along.  Devialet is a newish company based in Paris founded by ex-Nortel Networks engineers.  

Digital amplification is not a new concept.  Digital switching amps (Class D) were invented decades ago, but only perfected recently by the likes of Bang&Olufsen (with its ICE power modules as used in amps by Bel Canto, Wired4Sound, etc), Nuforce, and others.  Direct digital input pulse width modulation (PWM) amps are less common but there are several good examples around (Tact/Lyngdorf, NAD M2).  What Devialet came up with, however, is quite unique and combine the best of both worlds.  

Devialet calls its amp "Class ADH" where a small Class A amplifier directly coupled to the loudspeaker - tell the speakers how the analog waveform would look like, then another high efficiency Class D provides almost all of the current needed to drive the speakers.  The Amp is carved out of solid aluminum and weight 7kg and is designed to be driven digitally.  The digital to analog conversion happens very near the output stage and is as pure as it can be.  It uses, we 600 watt class D power supply with efficiency ratio of over 85%.  Idle power consumption is less than 5 watt.  Fully customizable configurations of RCA connectors, by using the website and save the config file on an SD card.

Early reviews from AVguide Absolute Sound, 6Moons, Hifi Choice, and Hifi-News and Record Review are saying the sound is extremely clean, dynamic, quiet and transparent.  The cost? $18,000 retail.

  • Stereo: 2x240 watt maximum output (programmable)
  • Impedance rage: 2-8 ohms
  • DAC chip Burr-brown PCM1792 (24/192)
  • THD+N: 0.001%
  • IMD SMTPE: 0.001%
  • Signal to Noise Ratio : 130 dB
  • Output impedance < 0.001 ohm
  • 2 x Phono inputs MC/MM
  • 2 x RCA analog line input (configurable)
  • 2 x Toslink digital inputs
  • 4 x Coaxial digital inputs
  • 1 x AES/EBU 
  • 1 x HDMI1.3 input and 1 x  output
  • 1 x RCA Analog or Digital 2.1 output
  • 4 x Speakers terminal
  • 1 x RS-232 port
  • 180 DPI color screen
  • 1 x SD card slot for upgrades and configuration

Pure i-20 iPod and iPhone dock

Another new iPod dock with digital audio Toslink and coaxial output from Pure Audio.  Also converts to analog using with resolution up to 24 bit / 192 kHz.  The i-20 is iPhone compatible.  All for GBP 85.


  • 24-bit 192 KHz DAC 
  • 105 dB signal to noise ratio
  • 93 dB THD+N 
  • 2V RMS output
  • Digital optical (TOSLINK), digital coaxial (RCA) 
  • Dual RCA analogue dual RCA audio output
  • Component (YPbPr), S-Video* and Composite video output
  • Remote control
  • Charges iPod/iPhone

Tuesday, December 21, 2010

HRT iStreamer

High Resolution Technologies or HRT, maker of the award-winning Music Streamer II Asynchronous USB DAC, just launched a new iDevice digital audio interface which allows high quality streaming of iPad, iPhone or iPod's audio (basically all modern iDevices).  

The iStreamer is the first Apple-approved outboard full-host-mode DAC (not camera kit work-around).  It takes the digital output from your iPod and uses high quality d/a conversion rather than using iPod's internal conversion which is of lower quality.  99% of the iPod docks available takes out iPod's already converted analog signals, not digital.  

To date, the first few units that extract digital data are Wadia 170i, Wadia 171i (iPhone compatible), and Onkyo ND-S1.  However these are transports only, no digital audio conversions.

iStreamer's specifications:
  • 16-bit only
  • 32, 44.1, and 48kHz
  • 2.25 v RMS output
  • S/N ratio of 98dB
  • Gold plated analog RCA output
  • iDevice input
  • Power port (USB A-type connector), which also charges device
  • Compatible with all modern iPods, iPhones, and iPads

Priced at $249.  Looks interesting and would be a killer device for iPad users.  However, I would like to see a version with a digital output.

Monday, December 20, 2010

Edovia's Screens app for iOS

Controlling your Multimedia PCs (Mac, Linux or PC) using VNC client protocol couldn't be easier and more elegant than the new $14.99 Screens app for iOS.  
Perfect for controlling the Mac Mini headless server streaming music on the hi-fi shelve in conjunction with the already excellent Apple's Remote app for controlling iTunes content, and Rowmote for everything else.


  • Universal - Screens will run on both iPhone and iPad - one app for both devices.
  • Easy to Use - Screens is the easiest, most user friendly VNC client for iOS.
  • Exit Cursor - Screens is a 100%, fully touched-base VNC client. Forget the cursor. Click, drag and scroll where your fingers are, not the cursor.
  • Secure - Screens can connect to your computer through a SSH Tunnel so your session is encrypted and safe.
  • Pull-to-Dock - Your Dock is hidden? No problem! Screens can make it appear with a simple flick!
  • Multi-Touch - Screens supports many multi-touch features your already use on your trackpad.
  • Screens Connect - Make your computer available from anywhere. Easy as flicking a switch! No messy router setup.
  • Versatile - Compatible with OS X, Windows and Linux.
  • Works Anywhere - Through WiFi or a 3G network.

Sunday, December 19, 2010

Consonance Orfeo and D-Linear 7

There are a lot of interesting digital audio companies out of China these days.  You have Shanling, Bada, Lite Audio, Valab, Yanqing, Audio G-D, and now Opera Audio from Beijing sold under the brand Consonance.  Some interesting models:

Consonance Orfeo non over-sampling CD player
  • Aluminum chasis (quite good looking) 
  • 4 x Philips TDA 1543 in parallel (lower output impedance and high voltage)
  • Non over-sampling
  • No digital filter
  • Passive I/V conversion
  • Quality parts

Consonance D-Linear 7 streamer

  • Touch color screen controls
  • 24-bit/192kHz compatible
  • 32-bit DSP
  • Decodes WAV, WMA, APE, FLAC, ALAC, ACC
  • Streams music from NAS or USB hard drive
  • SDHC card and USB host input
  • Streams internet radio 
  • USB wireless WIFI adapter available

Review: dB Audio Labs Tranquility USB DAC Signature Edition

I was skeptical on whether it's clever viral marketing or genuine raves from early adopters, but dB Audio Labs' Tranquility got my attention.  I was scouting Audiocircle and Audiogon forums and there were threads on the DAC with words describing it as "the best USB DAC money can buy", "Can't believe it's not analog", etc.  That keyword "Analog"  has always been the holy grail for most of us, so I felt I got to try it out.  dB Audio Labs also makes a non-signature version of the DAC ($1,495 vs SE's 2,395) , and two USB cables ($295 and SE's $395, $100 less when purchased with DAC).  There's a 30-day return policy and a limited-time $500 off current retail prices, so I ordered the signature version of the both the DAC and the cable.

Design and Technology
The Tranquility replaced my Bel Canto DAC 2.5 in my desktop system.  The Tranquility is a simple looking (sort of..DIY) silver aluminum box with only one USB input and one pair of high quality RCA outputs.  So simple that it does not come with an operating manual (dB Audio Labs has excellent support, and the guys there will guide you personally with any set up questions you may have).  There is an IEC power connector and voltage is set from factory either for 110v or 220v.  There is a switch internally to let you select a different voltage in case you want to use it in your holiday villa in Europe or Asia.  dB Audio Labs does not give detail of the DAC's components nor specifications.  Eric Hider, the proprietor, says that he wants potential customers to listen with their ears, rather than imagining what the DAC would sound like from reading its specs.  Fair enough.  However, we do know some features and design concept of this DAC from Eric's collection of posts from the afore-mentioned forums.  

The DAC chip set itself is 16-bit, and is set to run in non over-sampling mode (see earlier blog - The Rise of NOS).  The mystery chip is either a new old stock Philips TDA1541, TDA1543 or a Burr-Brown PCM56.  It accepts 44.1kHz to 48kHz sample rate.  Any input above 16-bit, or 48kHz is flagged by the USB implementation and correctly down-sampled by the computer, so you can still listen to your collection of hi-resolution music files, but at lower bit and sampling rate.  Non-PCM digital data (DTS or Dolby encoded) will just not play.  There are posts by people stating that the Tranquility does not use any digital filters but I believe it utilizes an analog low-pass filer (the box is small, and no way they could use a transformer output device to also act as a low pass filter a-la Audio Note).  Eric told me the output impedance is around 600 ohm and the output voltage are "hotter" than normal DACs (usually 1.5-2 Vrms).  The output of the chip set then fed in current ("I") mode, with a discrete current to voltage ("I/V") stage to the RCA outputs. Modern OpAmps will give lower output impedance, but of course discrete I/V stages do sounds better.  dB Audio Labs only says the Tranquility uses discrete class-A output stage and claims that their patented I/V stage is unique.

USB implementation is plug-and-play, no drivers needed.  To output sound through the DAC, you go to your computer's sound preferences and select output to "USB Audio DAC".  My understanding is that the implementation is adaptive not asynchronous.  Since the DAC itself is 16/48 max, and the computer will down-sample, it does not matter whether it does 96khz or 192kHz.  Although the DAC should work with any computer or device with USB audio output, dB Audio Labs used Apple Macintosh to "tune" this DAC.  Eric suggested that to get the best out of the Tranquility, you should go out and purchase a clean Mac Mini 2010 with the largest amont of RAM you can afford, replace the internal hard drive with a solid state drive, keep music in a separate high performance firewire drive (he even suggested the best unit he tested), disable unused memory resident programs and processes, connect no other USB devices, and use better software than iTunes such as Amarra or Pure Music, etc.  I was already in a process of getting a new Mac Mini to be the center of my new computer audio system so these advices came in handy in helping me optimize the computer for use purely as an audio server.  The Mini will stay and function that way regardless of whether I will keep the Tranquility or not.  But for those who do not own a Mac, or may use the computer for other tasks as well, knowing (or believing) that you are not optimizing your DAC, and the fact that it only has one type of input, may be a deal breaker.  This is clearly a niche product, but a very large niche that is, given the number of new Macs sold each month.  I also read favorable report from people with Macbooks, Windows, and even Linux machines.

Each of our definition of "vinyl" or "analog" may be different.  But if you are thinking "thick", "warm", and "laid back", the Tranquility is not that.  If you had heard decent vinyl play back, you would appreciated the fast transient, rounded-note impact, slightly forward presentation but at the same time never harsh on the ears.  The mid range would be lush without being too warm.  The frequency response would be evenly extended at both frequency extremes, and definitely not thick.  The most important aspect is the palpable life-like quality.  They just sounded more real.  The Tranquility delivers much of that promise.

I left the Tranquility running continuously, driven by my old Mac Mini 2008 without really listening to it for about 80 hours. Then I moved it to the new Mac Mini 2010 rig, replacing the Bel Canto DAC 2.5.  The Bel Canto was driving the power amp directly as it has digital volume and can function as a very good preamp.  At first I tried connecting the Tranquility direct to the power amp, but the digital volume control in iTune was very noisy especially at lower listening levels, apparently Apple's dithering algorithm is not very good.  I am alternating between two Mac OSX music player application, one is Ayrewave and the other being Audirvana.  Both are free for now, but their digital volume control over USB do not work with the Tranquility.  I understand that they will only work with Wavelength, Ayre, and Wired 4 Sound DACs.  Since the two programs are very good, I do not want to invest in programs with reported good dithering such as Amarra and Pure Music at the moment.  So in order to correctly judge the sound of the DAC without the nice and the nasty of a preamp, I resorted to LDR type passive preamps because of their well-known transparency.  I alternates between George's Lightspeed attenuator (which is super transparent) and DIYparadise's EVA2.  These provided volume control for the DAC.

The first thing that comes to mind after the swap is the opening up of music.  There was more "air" to everything.  The Bel Canto's presentation was somewhat denser and slightly compressed by comparison.  The mid range, not only volcals but everything else including background instruments, was very clear, smooth and liquid with the Tranquility.  Many people were saying the midrange of this DAC is like mercury, I now know what it's like.  Everything seemed to sound easier on the ears even with rock and electronic music.  All this did not come with smearing of sharp transients.  Macro dynamics were extremely fast and instantaneous.  The music seemed more real and sounded less hi-fi.   

The sound stage seemed to "float" and separation of instruments are placed more distant from each other.  However, specific placement of instruments were less focused.  There were  haloes surrounding the instruments.  In more complex music, the tonality and palpability were superior to the Bel Canto, but you couldn't pick out the instrument clearly as before.  Overall, the soundstage seemed more believable.  The stage was not particularly deeper nor wider, but they were higher in scale.

The high end of the frequency spectrum is harder to describe.  It is very extended with plenty of air.  The highs were relaxed and some tracks with lots of zings are less pronounced, but at the same time you do not have the feeling of high frequency roll off.  The sharp edges (cymbals etc) were rounded but with impact, you could hear the stick touches the metal.  It had clarity without any trace of  harshness.  This is a quality only high performance DACs can achieve (the Weiss has similar qualities).  I guess dB Audio Labs might have designed this DAC with a low order filter as opposed to a brick wall filter.  

Bass was tight and controlled.  However it lacked the slam and weight of the Bel Canto.  There is noticeably less energy down there and it seems to be slightly rolled off.  The fundamentals were there and it fits nicely with the Tranquility's overall presentation, but if you are a bass buff, you might find this slightly less than ultimate.  However, it may be the case that there was an impedance mismatch between the DAC and the passive volume control.  (Eric suggested that the input impedance of the preamp should not be less than 50k ohms, the Lightspeed's impedance varies depending on the attenuation). 

Over the past week, I also had on hand the excellent Weiss DAC202 firewire DAC for comparison.  The DAC2o2 was connected through firewire over normal cable.  I copied and played music files directly from internal SSD drive to free up the firewire port.  All I can say is that the $6,670 DAC202 is superior to the Tranquility in many areas, but could not beat the Tranquility's mid range which was clearer, smoother and more liquid like.  It is a mid range to die for.  However, it could not match the Weiss's "cover-the-whole-wall" scale, refinement, and super articulate bass, the latter is even better than the Bel Canto.  Micro-dynamics while very good can not touch that of the Weiss.  But hey, it's three times the price!

As reported, high resolution music are down-sampled to either 44.1 or 48kHz.  I am happy to report that even with Hi-rez, all my comments above are still valid vis-a-vis the Bel Canto.  The files played fine and actually sounded better in those areas via the Tranquility.  I never heard a better sounding Jazz at the Pawnshop (88.2khz version) before.

The Tranquility is one of those niche products.  If you are planning a computer-based high end stereo and can live with having nothing but computers to stream music, you owe yourself a listen.  It gives you fatigue-free listening experience rarely achieved by any products regardless of price.  If you hear the clarity of its highs and liquidity of its midrange, it's really hard for you to go back.  For me the Tranquility is a definitely keeper and a match made in heaven for my new Mac Mini, so I won't be claiming that 30-day return policy.  
Highly recommended!

Red:Tranquility SE    Blue: Weiss DAC 202

Saturday, December 18, 2010

Olive O6HD Music Server

Olive is taking pre-order (as of Dec 2010) for its new Music Server, the new O6HD.  Seems to provide the right tick box for sound conscious techno-audiophiles.


  • Solid aluminium enclosure with anti-vibration feet
  • Quiet passive cooling
  • Browse covers of up to 6,000 CDs on its 10.1" 800x480 pixels glass color touch screen
  • TEAC CDRW mechanism for importing CDs direct.  Drive also burn Audio CDs and MP3
  • Balanced differential DAC design with dual Burr-Brown PCM 1792 24-bit
  • Ultra low jitter master clock
  • High end sample rate converter (up to 24-but/384kHz)
  • Linear power supply with toroidal transformer for analog output stage
  • High performance current-feedback headphone amplifier
  • Ultra quiet 2TB hard drive
  • Support WAV, FLAC, AAC, and MP3
  • AES/EBU, Toslink, coaxial, HDMI and USB input
  • XLR and RCA output
  • Access to internet radio
  • Olive O2M multi-room compatible
  • Olive for Apple iPhone application for remote controlling
  • Available in black or silver

Friday, December 10, 2010

Review : Wadia 151 PowerDAC mini

Wadia Digital, one of the greatest name in hi-end digital, has jump into the computer/desktop audio band wagon with the Wadia 151PowerDAC mini.  The 151 is basically a DAC and Integrated amplifier in one compact 8" square box - only slightly larger than a Mac mini.

Wadia, founded in the late 80s, was one of the earliest companies specializing in high-end digital audio products. Founded by former 3M engineers, they came up with concepts way ahead of their time and in fact is the first company to come out with a stand alone DAC for hi-end audio.  Their Digimaster algorithm was legendary.  The Wadia 2000 was unmatched technologically and sonically at the time.  Wadia was one of the first company to recognize the role of jitter in digital music reproduction, and was the first company to apply a digital volume (in modern audio application context), and lately the first company to extract a true digital output from the iPod with their Wadia 170i dock (others merely analog audio pass through using internal iPod internal conversion).  One thing that Wadia has never done before, was producing an amplifier.  the 151 is their first amp.

Design and Technology

My unit is in matt black, but there are also available in silver-white color.  There are 5 rubber push button in the front panel: input, phase, mute, vol - , vol +.  A two-line black lit bluish LCD display which can be turned off using the supplied remote which also controls all other functions.  At the back there are two RCA SPDIF digital inputs, one USB, and one toslink as well as standard IEC power connector and  standard plastic 5-way binding post.  There are no analog inputs nor outputs - so you can't just use the DAC nor the amplifier (its PWM output amplifies directly, so difficult to implement line out, bad news for Headphone users).  The Wadia 151's chassis is the same size and shape with the 170i and can be stacked over each other nicely.  Cute!

The 151 uses trickle down technology from higher end Wadia decoding computers (their fancy way of calling their DACs).  Most notably is the asynchronous up-sampling and DigiMaster algorithm. If you use an imaginary microscope, all the audio analog sine waves are stair steps because of the sampling rate.  Wadia 151 up-samples all inputs to 384kHz (from 44.1 - 192kHz) and apply an intelligent "forecasting" based on their model spline curve on what the analog sound curve should look like.  This is done through a "very accurate" master clock which they claim to reduce jitter to astonishingly low levels and create an audio signal that is so close to real life analog sound waves.   The volume control is done in the digital domain at 32-bit resolution, so even at -50db the resolution is never less than 16-bit.  

The signal output from the previous stage are converted to pulse width modulations (PWM) which are amplified directly through a low-pass filter to drive the speakers.  The amp is a variation of the class-D design and is rated at 25 watts into 8-ohm and 50 watts into 4-ohms.  The 151 consumes only 4 watt when idle and is designed to be left on indefinitely, and my test shows that it sounds better after 30 minute after turning on.

The connectors are of good quality, except that of the coaxial digital inputs.  My digital cable termination was quite tight fitting and I was trying to pull it off by turning but ended up unscrewing the SPDIF post off from its place.  I would expect a higher quality connector from a company like Wadia.  Fit and finish are good generally but I would like to see better screening of letters on the front panel.  They are just screened painted and looks cheap (although higher models from Wadia also uses this method, but somehow managed to look "more expensive").  Well, what to complain at $1,195??

All my listenings were done after running signals through it non-stop for a week.

First thing I want to say is that I didn't expect a sound like this from a small little box!  It sounded...well, BIG.  It played louder than I would expected from a 25 watt amp.  My reference desktop speakers, the Amphion Argon3 speakers, are not very sensitive (rated at 86dB) and are usually better off with more powerful amplifiers.  However, there were never a sense of strain or stress on the 151.  I turned the volume up, filling up a medium size listening room with no sign of the 151 running out of power.  They felt as powerful as my Bel Canto s300 in terms of ability to drive.  However, macro dynamics (changes from softest to loudest) were slightly lagging from the the more powerful amp.  The slam emerging from quietest black background lacked the last bit of heft and immediacy, but I am nitpicking here.  Bass was tight and solid, but if you like bass extension and slam, you may think the 151 is a bit lean sounding, but I find it is neutral and well balanced, neither thunderous nor thick.  This is not a warm sounding DAC, it just doesn't have a character per se.

Micro dynamics, the small little details and nuances are among the best I have heard.  The all-important mid range is clear as crystal, this make the 151 sounds sophisticated and is a great match with certain kinds of music such as jazz or acoustic recordings.  The 151 is highly resolving and never edgy or grainy.  The word "refined" sums the tonality of this unit very well.
Soundstage is very good.  Sound field extended backwards compared to the Bel Canto DAC2.5.  Vocals seems to move a foot backward.  Width is good and instruments are well spaced out but soundstage seems to not go much beyond the speakers (Weiss DAC202 excels in this area).

USB implementation is adaptive isochronous, not asynchronous, but with well implemented super up-sampling and an accurate master clock this is probably benign.  The more expensive Wadia 781i also uses this method.  I tested the USB input and finds it to be as good as, if not slightly better than its SPDIF toslink input (driven from Mac mini optical output).  I did not test the coax RCA input as I did not intend to use this DAC to decode anything but music from my computer, so can not comment there.  

The only usability issue I have seems to be the inability to decode 88.2kHz.  The 151 can only do everything else except 88.2 kHz, which is a shame because many of HDtracks' excellent downloadable hi-resolution music are at this sampling rate.  The sample would be down sampled and locked at 44.1kHz, then up-sampled again, which is less than ideal.  USB and toslink are both limited to 96kHz (former because of the DAC, latter because of the toslink implementation in the Mac hardware), so if you want to get 192kHz, you need to get it from a PC with capable sound cards, or newer 192 capable USB to coax SPDIF converters.  See A survey of converters in the Blog archive.

(I was later informed that the 151's coaxial and toslink inputs, but not USB, can accept 88.2kHz.  However the Mac OSX does not output 88.2 over toslink, so it didn't work for me.)


Since we can not really judge the 151 as a stand-alone DAC or integrated amplifier, I can only say that you can't get this sort of performance from a $500 DAC + $700 amp, you will have to spend closer to $2,000 to get this level of sonics.  It's obvious competitor is the Peachtree Audio Nova (Hybrid tube integrated amp and DAC).  I have not heard the Nova but heard good things about it, so please try to audition the 151 vs the Nova and see which one touches your soul.