Your Computer Turned HiFi – Channel Islands Transient MK II USB Converter

Channel Islands Audio Transient MK II photo by Vahan Baladouni

Channel Islands Audio has been producing high quality audiophile products for over 15 years. Situated along the Pacific coast and near wine country, this small audio firm builds some unique stereo gear with clean modern case work. While always being interested in these tight industrial designs, I never had a chance to actually hear one. That all changed after I spent several days at T.H.E. Show Newport. Listening to CI Audio amps, passive preamps, and DACs was a treat and had me asking for more. Fortunately, I was able to take a closer look at one of their latest designs.

Under development for 2 years, the Transient MK II represents CI Audio’s research into USB to digital audio conversion.

Removing the hood of this converter reveals a XMOS based asynchronous USB input with low jitter clocks. This asynchronous method allows the Transient to act as the master audio (sample rate) clock for your computer audio. By using two sample rate clocks all the usual suspects are available; 44.1, 48, 88.2, 96, 176.4, & 192Khz. Combined with a galvanically isolated S/PDIF on 75 ohm BNC, this USB converter provides a clean way to interface with your favorite DAC (Digital to Analog converter). It even goes further, to provide I2S outputs via 5 pin DIN and HDMI. These I2S outputs separate word clock from data stream, and a handful of Hi Fi companies have begun using this interface*. Even if you don’t use the advanced I2S outputs, the true 75 ohm BNC S/PDIF allows for correct impedance when connecting to a DAC of your choice.

A look inside. Constucted from double sided glass/epoxy circuit boards w/ 2oz copper traces. Note: XMOS board, carefully selected parts/high-speed ribbon cable – Photo by Vahan Baladouni

With a clean modern faceplate, this unit has an industrial refinement about it. The sample rate is easily seen by one of six blue LEDs that indicate a lock. Steel hardware against the aluminium chassis provides a tasteful contrast, and the tactile feel of the precision machined volume buttons exemplify build quality. It is evident that a keen eye laid out the chassis design, for even the rubber feet and front logo have a machined inlet for their precise placement. Powering is simple – the Transient pulls direct current from your USB port, making it truly portable. Taking it a step further, the VDC-5 MK II power supply can be purchased for those wanting to squeeze out every last bit of resolution.

The VDC-5 MKII power supply and Transient II USB converter – 2V RMS and mute setting are quickly engaged by pressing/holding one volume button and pressing the other – photo by Vahan Baladouni

While the USB to Digital Audio conversion is the primary purpose, CI Audio has also included a built-in DAC (Wolfson) with RCA outputs and digital volume control**. Those neatly machined volume buttons also allow quick-setting of 2V RMS output for a proper analog level to feed your preamp. Even without a pre-amp,utilizing the built-in volume allows you to plug directly into an amplifier. This type of digital volume maintains excellent L/R channel separation, but for listening at lower levels a separate pre amp may be prefered.

Transient MK II and VDC-5 MK II rear. Connections include true 75 ohm BNC and i2s over DIN and HDMI, and DC input for optional power supply…don’t forget the DAC RCA outputs! photo by Vahan Baladouni

Transient MK II/Listening to the USB to S/PDIF conversion

  • Speakers: Green Mountain Audio Eos HX
  • Source: Macbook Pro w/ Pure Music
  • DAC: Crane Song Avocet
  • Amp: Anthem MCA-2
  • Cables: Audio Magic, Shunyata, DH Labs custom BNC to RCA

With a Macbook Pro running Itunes and Pure Music, I tried the Transient MK II as powered with DC from the USB connection. For this trial, my Crane Song Avocet was the DAC and I fed it from the Transient’s S/PDIF output. Audio MIDI setup quickly recognized the attached USB Audio device, and so did Pure Music.

Now I was ready to dive into some tunes. I decided to try the standard red book CD sample rate of 44.1. Without a hiccup, all the audio files played back. I found the CI Audio unit to present a solid digital signal that my DAC could easily decode. Listening to Beethoven symphonies conducted by Karajan was simple and musically involving. The width and depth of the concert hall was spacious and localization was very clear. Not only were these some fantastic recordings, but the Transient II transmitted the data without error. With more obvious resolution, I began recognizing the superior image stability and reverb tails with the Transient’s USB to S/PDIF conversion. Having used a variety of computer audio interfaces, the Transient MK II’s ability to transmit all the digital data started to become evident. This brings me to another point; even though some DACs can do jitter reduction (i.e. Crane Song Avocet), feeding a DAC a lower jitter signal will always result in cleaner audio reproduction – the Transient MK II uses custom sample rate clocks with less than 1 psec of Jitter.

Moving on to hi-resolution audio files (24 bit/ 88.2 and above) was a cinch. A quick change of the sample rate in Pure Music had me listening to Stevie Wonder at 96khz. The Transient MK II obediently changed sample rates with LED indication, and the music commenced. 24/96 transmitted without any issues and sounded great. Stevie Wonder’s multitracked clavinets smacked some funk with clean articulation and all the harmonic content. I even cued up some stereo 24/96 SFX I recorded and was impressed at the image stability, and clarity. The clean resolving presentation of the Transient became very obvious even when low-level SFX were played. Using the Transient for my professional audio needs was certainly a no-brainer.

But, what about upsampling standard 44.1 files? By allowing your computer/Pure Music to do the upsampling in 64 bit mode, the math can be done very accurately. This allows the Transient MK II to act as master clock for your upsampling requests. Upsampling an old Count Basie recording (Japanese transfer) proved to be quite worthwhile. Moving from 44.1 to 176.4 was a fun experiment. I for one enjoyed the sound presented this way, and felt that a smoothness was brought to the presentation. If you consider digital recordings harsh, this may be the way our ears respond to different degrees of filters present at different sample rates. With the solid master clock of the Transient MK II, you can experiment with upsampling and choose what sounds best to you.

VDC-5 MK II Power Supply

Channel Islands also offers an optional power supply that provides high current and low noise for the Transient MK II. This unit cosmetically matches the Transient, and eliminates the use of DC from your computer’s USB port. Since the Transient smoothly switches between computer power or the VDC-5 MKII, it was easy to hear the differences with and without it. Bass definition, extension, and stereo image stability were noticeably improved when using the seperate power supply. While these differences were heard by several friends, it was most impressive how well the Transient operated on USB bus power alone. Those with highly resolving stereo systems may want to consider the upgraded power supply.

Transient MK II provides DAC conversion for vintage Marantz 1090 stereo receiver – photo by Vahan Baladouni

As an additional feature, the Transient MK II has a built-in DAC. My friend Jin was interested, so we decided to test it out on his vintage Marantz system with Wharfedale speakers. After speaking with the designer (Dusty Vawter), I was told the Wolfson DAC has been carefully implemented to extract the best possible sound. Regardless of the DAC being a secondary feature, I thought the sound was indeed musical. Using the analog 2V RMS output into the Marantz 1090 proved to be quite lovely. More so, the presentation was clean, smooth, and involving. The tonality of instruments were natural and voices sounded equally organic. While arguments can be made for the various differences in a DAC’s sound, the one thing that stood out was that nothing stood out. No exaggeration of the audio band, just clean audio that was easy to engage and listen to for hours.

The CI Audio Transient MK II brings Hi-Res music & Internet Radio to your HiFi! photo by Vahan Baladouni

As my friend and I were trying out the Transient MK II, we decided to check out some internet radio stations. I quickly found WWOZ, my local radio station in New Orleans. Soon, we were listening to Jazz and Funk from the Crescent City! USB converter, DAC, Hi-Res audio, and discovering internet radio through my HiFi…This little device brings a world of music into your home. You’d be surprised how good some of these stations can sound when converted through the Transient MK II. Sure, these weren’t Hi-Res audio streams, but the content was never-ending – that could now play through my stereo! This was certainly icing on the cake, and hours later we were still listening to various radio stations from around the world.

With modern sleek looks and smooth operation, the Transient MK II excels at getting the most from your computer audio. The build quality and value truly makes this product stand out. Without reservation, I highly recommend looking into this superb USB converter!

The Transient MK II includes a USB cable, one BNC to RCA adapter, and a 5 year warranty. Click here for information on Channel Islands Audio.

Transient MK II – $699.00

VDC-5 MK II – $329.00

Follow-up:

DAC section

My overall impressions with the Transient MK II were very good. While I have heard DAC sections that resolve more absolute detail (and twice the price), the analog output provides even sonics with no exagerations in the audio spectrum. The quality of the analog output made it enjoyable in all the systems I tried; Luxman L-550AX, Marantz 1090, & the NAD C 725 BEE. The Transient as a pre amp into my Anthem MCA 2 was a clean & imidiate sound. My biggest impression – this device has quality and portability that I have never experienced in a compact USB converter. This device makes it easy to share your quality recordings on friends stereo systems.

Digital conversion:

The USB to S/PDIF conversion works much better, and more reliably than my Yellowtek Puc2 USB asynchronous converter. I suspect several things that are contributing to this; understanding high-speed USB 2.0 and how to fully implement it for all sample rates, XMOS, custom word clocks, galvanic isolation, and proper s/pdif impedance.  All the sample rates work with no fuss!

*I2S is a digital audio connection being adopted by several audiophile manufacturers including Audio Alchemy,Perpetual Tech,Camelot, PS Audio…some Future CI Audio products will include this input connection.

**Connecting the DAC output directly to my Anthem MCA amp and Eos HX speakers was very worthwhile. The sound was quick, clean and without any added color or tone. This feature is great to compare your own line stage/pre amp to.

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Ripping your CD collection into iTunes

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XLD ripping software places ripped audio in iTunes music folder

If you are about to embark on ripping your entire CD collection to your external HDD (maybe a SSD, cool!) and question iTunes reliability, you are not alone. iTunes rips CDs to your internal or external hard drive with features such as error correction. While this may work, iTunes fails to offer any report or validation that you have indeed ripped your CD without error. If you’re about to rip hundreds or thousands of CDs like I did, you may want to investigate other methods.

XLD* is a Mac OS based CD ripper that uses AccurateRip technology. XLD has been around since 2006 and has undergone many updates and enhancments. Not only dos it rip CDs accurately with detailed reports, it also seamlessly migrates your ripped CD into your iTunes music folder. It also supports metadata so your album art and titles are found and married to your CD rip.

-Happy ripping

*XLD is a free software download. If you enjoy the quality of this software you are welcome to donate.

File format support: aiff, wave, apple lossless, flac, mp4 (2 types), LAME mp3, Ogg Vorbis, WavPack…..

Computer Hi-Fi

Achieving bit perfect playback with zero interference is the goal, right? I will use this post to explore my findings with computer based stereo systems. Here’s some of the equipment I tested out.

For this test I used an Apple Macbook Pro for my audio playback system. The Macbook Pro supposedly has better RFI (radio frequency interference) rejection than the Mac Mini. PC’s are also possible playback computers, but this article will relay my Macbook pro experiences.

Building a Hi Fidelity computer based audio server/player can often present some challenges. While iTunes organizes music well, it doesn’t play it back with the highest fidelity. Enter the software developer. In recent years we have seen a variety of playback software come onto the audiophile market. This software, such as Pure Music** and Amarra allows iTunes to open and be used as a GUI while pure music handles all the audio processing. Features like RAM memory playback, upsampling, and turning off handshaking allows digital music to be reproduced with less artifacts/jitter.

Computers are notorious for producing noise. Not only do the fans make acoustic noise, but also the graphics card, processors, and other components produce power line noise. This hash is transmitted down USB, Firewire, and other ports that transmit DC power. The sensitive clocks that produce the sample rate in these USB/Firewire DACs are affected by the noise transmitted down the busses DC leg.

The German-made Yellowtec Puc 2* USB audio interface converts USB to AES for the Crane Song Avocet DAC. Providing clean power to the USB powered AES interface is of utmost importance. In order to tackle this issue I first start by separating the digital and analog audio gear. Shunyata hydra 2 units are used for this purpose. The DAC/Monitor controller gets AC power from one hydra 2, while the stereo amp is plugged into the other Hydra 2. If I had the ability, I would place each of the Hydras on their own dedicated AC circuit. Furthermore, I have the computer on a separate circuit with a surge protector.

Other products exist from companies like AQVOX that allow you to lift the DC power from the computer and insert a separate power supply for your USB device.

I will continue to relay my findings as I explore this topic more. Stay tuned…

The Yellowtec sounds best when operating on internal clock, as do many converters. The Puc 2 also benefits from clean power via the previously mentioned methods.

*The Yellowtec Puc2 is asyncronous and can be locked to an external word clock via AES-3 connection. The Benchmark ADC-1 was tested and provided rock solid clock to the Yellowtec Puc 2. Rock solid when locked to 44.1 and 88.2 via AES-3 signal from ADC-1. At higher sample rates, the Puc2 seems to prefer its internal clock.

**Pure Music sounded best when used in 64 bit mode and power of two upsampling enabled. For redbook CDs that were 44.1 SR, upsampling to 88.2 via Pure Music provided the best sound. The 88.2Khz Clock was provided via the Yellowtec Puc2. DSP functions on Pure Music “off” except for upsampling/meters off and in “Less is More” mode.

*** All USB ports on the macbook and mac mini are not created equal. Some of the ports share other busses such as isight, IR, and bluetooth. You can also disable the IR receiver in system preferences.

A usb cable that separates the DC power leg from the data wires with spacing and shielding is recommended. I use a Wireworld usb cable with this key design feature.