Channel Islands E•200S Stereo Amplifier

Channel Islands Audio E-200S Front Panel

The last time I tried out some of Dusty Vawter’s amps I was toting two hefty monoblock amplifiers down the Pacific Coast Hwy. On this journey, my payload was significantly lighter. The E-200S stereo amplifier box fit snugly into the back of my Subaru, and once home, this small unassuming amplifier took center stage powering my 2 way speakers- Green Mountain Audio Eos HX.

Getting it out of the box, was a snap (14.0”W x 2.75”H x 10.0”D). The size and weight of this amplifier made setup and handling a breeze. While the front panel grants access to an on/off button with blue LED surround, the host of usual connections can be found on the amp’s business end. Whether you choose RCA or XLR inputs, the custom differential input stage is used. Then an updated UcD Class D stage drives the output. Speaker binding posts are insulated and accept spades or bananas, and a trigger input is also made available. Power cable plugged in, and we are off.

200 watts per channel @ 8 ohms/ 400 watts per channel @ 4 ohms

For music, I used a Macbook Pro running iTunes/Pure Music 3. The DAC was my Crane Song Avocet, and the Antelope Audio Zodiac Platinum. With everything connected via balanced cables and several hours of warm up (this amp had already been burned-in) I was ready to start listening to some of my favorite tracks.

I cued up some acoustic music by Kings of Convenience. This Norwegian duo offers a great starting point to evaluate the naturalness of the male voice. Listening to “Rule My World” from “Declaration of Dependence” gave me some lovely acoustic guitars with harmonizing male vocals.

View from above, notice the small footprint

The two part acoustic picking of “Declaration of Dependence” maintained all the midrange richness while allowing the male vocals to almost float above the gentle picking style. The clarity of guitars and male voices were presented in an un-hyped and natural way.

Moving onto more complex works, I began listening to Herbie Hancock’s “Steppin’ in It.” This groove laden funk from Mr. Hancock’s “Man-Child” album features rich synth leads, a tight bass lines from Paul Jackson, and a stellar harmonica solo by Stevie Wonder. Allowing all that musical articulation to shine through requires some control over loudspeaker movement. The E200-S gripped My Eos HX and allowed each and every bass note to come through with precision and depth. While everyone in the band holds down the groove, Herbie takes the Rhodes for a stroll… and before you know it Stevie Wonder is syncopating a harmonica unlike I’ve ever heard. With each breath, a new note even funkier than the last is pumped out. All these counter rhythms and complex instruments can be demanding on an audio amplifier, and the CI Audio E-200S never slowed down. In fact, the intricate stereo soundstage was expansive. To top it off, the tonality of instruments (even the squeaky high harmonica) never sounded dull or harsh.

To verify the neutrality, I relied on several orchestral and vocal ensemble recordings I made for NPR, all at the same performance hall. While less capable amplifiers have shown some distortions or break-up, I’m happy to report that the CI Audio amp had none of those shortcomings. Localizing mic placement, hall width/depth, and reverb decay were all amplified without coloration. This provided a sonic portal to the original recorded events, an immersive experience indeed.

Spending time with the E-200S was revealing in so many ways. From black quiet backgrounds to fully erupting orchestral performances, this little beast was in control. Most of all, this CI Audio amplifier proves that green design and audiophile sound need not be mutually exclusive.

Happy Listening

Oyaide Electric Company; A Materials Science Approach to Power Distribution

Power Distribution Parts by Oyaide Elec & Acrolink Japan

The Japanese hi-fi market exists alongside a healthy DIY audiophile scene. The Akihabara neighborhood of Tokyo is a great example. One step off the Sobu line and a world of electronics specialty stores become available for professionals and hobbyists alike. One of my favorites, Oyaide Electric shop provides cables, connectors, and parts for building your own audio, video, and power cables/distributors.

Oyaide is a long established electrical wire company that  has been in business since 1952. Over the last 30 years they have grown to develop products for the audiophile and pro audio markets. Materials for Oyaide Elect. are developed and produced in Japan with a combination of technological innovation and traditional craftsmanship.

 P-004 Beryllium Copper no plating hand polished by traditional Japanese craftsmen

Oyaide power distribution materials are carefully auditioned and produced to provide tonal options for audio enthusiasts and professional musicians. Both the AC wall outlets and power plugs from Oyaide have been developed with several different base alloys and platings.

Their standard 15 amp Power plug and IEC connections (P-004/C-004) have become available with and without the plating of platinum and palladium. This has allowed me to listen to various power cables (Acrolink, Oyaide) and hear how they interact with different plugs and outlets- giving me a better understanding of what the AC conductors sound, which inludes: dielectric materials, shielding, plugs and ultimately the outlets they interface with.

After investigating several brass alloys, I have come to appreciate the sonic qualities of the Beryllium Copper alloy when used for AC power in highly resolving audio systems. Beryllium Copper is used for its spring like qualities combined with electrical conductivity. This alloy has corrosion resistance and maintains its original shape due to its ductile properties.

The Oyaide R0 AC duplex is made of beryllium copper for the contacts and PBT (with 30% glass) for the thermoplastic outlet face. Mechanically, the Oyaide duplexes provides excellent AC blade retention, and the PBT and glass filled body helps dissipate unwanted vibration. The R1 employs the same construction but adds a plating of platinum and palladium to the AC receptacles base alloy.

Homemade Power distribution with Oyaide MT UB Power tap case, R0 & R1 outlets

To satisfy my curiosity, I built a passive power distributor from Oyaide called the MT UB. This 2 mm thick brass and nickel/chrome plated 2 duplex box exemplifies Japanese craftsmanship. Four separate mounting poles with special washers allow each duplex to be well isolated from each other. I wired it with high-purity Japanese solid core copper and used one R0 un-plated beryllium copper duplex and one R1 plated with the platinum and palladium. I will try and describe the sonic differences of each outlet below.

Oyaide R0 duplex: This un-plated Beryllium Copper AC outlet provides an un-hyped and natural soundstage when used on analog and digital equipment. Compared to several other outlets with various metal platings, the R0 has provided me with the most neutral sonic presentation, a robust and taut distribution of power without any accent in the audio band. The R0 excels at dynamic sound with full energy at all octaves.

Oyaide R1 duplex: Beryllium Copper plated with platinum(0.5 μ) + palladium (0.3 μ). This outlet helps create a sound of focused and refined sonic presentation. While the un-plated R0 maintains an organic flow to the music, the R1 also adds a sense of lowered noise floor with some equipment, and I found that digital gear and video (improved contrast and blacks) benefited most from the R1 outlet. While I still hear a neutral presentation (Sonically), the R1 has a highlighting or spotlighting ability, albiet subtle.

Over the last decade I have been experimenting with various aftermarket power cables and power conditioners. Sometimes with fair results, and sometimes the cables or conditioners have effected the sound negatively. Starting with a materials based approach, I have been able to better understand how different conductors, dialectics, plugs, and  AC receptacles will effect the sound quality of professional and audiophile sound systems. Oyaide Electric company has provided a basis for AC materials to be judged in audio systems, see for yourself.

-Happy Listening

Caution: AC power distributors and cables are serious and should only be built/worked on by trained/licensed professional electricians.

Crane Song Avocet with Quantum DAC

David Hill of Crane Song LTD builds some genius pro audio equipment. His mic pre amps and compressor designs have always held a special place in my sonic memory. I’ve been lucky enough to use his gear in broadcast studios and through my own personal music recordings.

The Crane Song Avocet is a Class A monitor controller with a built-in DAC (Digital-to-Analog Converter). Having undergone 5 iterations, the current  Quantum DAC boasts impressive jitter specs and uses a proprietary reconstruction filter for accurate time domain response. Operating asynchronously with a 32 bit architecture, the reference clock is less than 1pS and all digital inputs are up-sampled to 211Khz.

Upgrade Note: If you are sending in your Avocet for the Quantum DAC upgrade, you will receive an optical input that replaces the original dual wire AES input. Cool, now you have AES, S/PDIF, and Optical.

The design is utilitarian and solid- sporting a modern industrial build with primary colored buttons and center volume knob. This might sound strange, but it always reminded me of Jacque Tati and his modernist take in films like Playtime (go to 23 sec). Monsieur Hulot would surely get lost in the maze of colored square buttons ;). The Avocet proves smart modern design can improve the future for all…err, yeah that is… for Audio Engineers!

Talking with David Hill at AES last year revealed his excitement about this new Quantum DAC design. In particular, David felt that the combination of filters being analog and some digital help provide a more realistic impact of sound. His words, if I remember correctly were, “a snare hit now sounds more like the real snare.” Now that I had Mr. Hill’s new Quantum DAC in hand, it was time to test it out.

To listen, I brought the upgraded Avocet down to a studio with Lipinski speakers and amps. There, we also had a previous generation Avocet to listen to and compare. A good hour of warm up was given, and a couple more listening to various digital audio sources from the SADiE DAW. Quantum entanglement aside, we began listening to this latest generation DAC design from Crane Song.

Using some familiar music tracks, we fed the Quantum DAC via AES/EBU, then out to the Lipinski speaker system with amps. It certainly sounded good right off the bat, but only after spending a little time did all the new sonic upgrades become clear. Switching to the previous generation Avocet DAC proved that this new design provided a more robust or dimensional envelopment to sounds. David was right about the snare sound. Even more, the guttural impact of kick drum was solid and more 3D. Instruments achieved a more realistic timbre and acoustic space with this Quantum DAC upgrade. While the previous generation DAC is no slouch, this new design allows a more fleshed out roundness to the instruments in the stereo image. The user-interface offers simple and functional controls that allow you to smartly and intuitively work. With the precise relay based volume control (with offsets for level matching) and brilliant class A output stage, the 5th generation Quantum DAC furthers audio resolution while maintaining full control of your audio sources. The Crane Song Avocet maintains its place as the hidden gem of my audio experiences. My highest recommendation.

-Happy Listening!

The State of Digital Audio Cables

 

Audioquest USB cables for digital audio, Coffee in focus

After recently writing about solid core audio cable designs, I began listening to various digital audio cables.  To dig in, I started by examining the transmission from computer to DAC (digital-to-analog converter) via the Audioquest USB cable line. For this listening test I employed the Antelope Audio Zodiac Platinum DAC with 10m Clock – simply connected to amp and speakers (Lipinski, and Green Mountain Audio).

The basis for the Audioquest designs start with solid core copper, then they add silver in varying amounts, a noise dissipation system, and finally a DBS or dielectric bias system.

Starting with a generic USB cable I familiarized myself with the sound. To be fair, I listened to several generic type USB cables…not all are created equal, and yes some sound decent too. After establishing the best sounding generic USB cable, I began exploring the Audioquest designs.

The Pearl, a basic LGC (long grain copper) USB cable was implemented from computer to DAC. Compared to the generic USB cable, the Pearl provided a modest but noticeable step up in clarity to the music files. The Forest, with its mere 0.5% silver over copper was easy to distinguish from the sound of the Pearl USB. A distinct and greater clarity came upon first listen, and continued use proved it more detailed indeed. A layer of background vocals was now more apparent. Moving past the Forest, one encounters the Cinnamon USB. At 1.25% silver over copper, this is still in the range of affordable USB cables (ok, for music lovers). The Cinnamon is yet again, more resolute. Not just more resolute, but better controlled and more balanced than the Forest. Next up, the AQ Carbon USB employs a whopping 5% silver over copper. This is also where Audioquest begins adding a 3 layer noise-dissipation system around the USB cable. If the Cinnamon was better balanced, the Carbon adds a more relaxed presentation – possibly due to less noise riding on the conductors. The Carbon also provided a greater sense of depth.

The last two USB cables in the Audioquest line include a 72v DBS (Dielectric Bias System). First up is the 10% silver over copper Coffee USB cable. After noticing the obvious clarity, balance, and extreme quietness (no background hash), another characteristic to the stereo field becomes apparent. Stereo height and depth information becomes easily distinguished. The arc of sound in the stereo field becomes less congested. Low, Middle, and High frequencies have a specific horizontal plain they reside in. Using the Lipinski Speaker system with subs (in addition to my 2way speakers) made this very obvious.

What comes after 10% silver, well 100% PSS (Perfect Surface Silver) of course. The Diamond USB is the most expensive offering from Audioquest. This USB cable spotlights ultra clear transmission while still being hash-free. Like Coffee USB, the Diamond possesses quiet backgrounds, great dimensionality, and rendering distortion free audio signals. Where it differs in sonic presentation is in the stereo height or arc. Compared to Coffee USB, I found the Diamond to create even greater distinctions between low, middle, and high frequencies. Specifically, center vocals were presented physically higher above the speaker than with the Coffee. While some stereo system might benefit from the Diamond, we found the Coffee USB to have the best overall balance in our systems.

Audioquest Coffee AES/EBU

To test out the Audioquest AES/EBU cables, I used my trusty Yellowtec PUC2. The PUC2 is a USB to AES converter. This allowed me to listen with basic Canare AES/EBU cables and compare them to the Audioquest designs. Note: I used the same AQ USB cable as AES/EBU cable being tested, for the Canare AES/EBU I used a generic USB cable to connect the PUC2 to computer. Canare AES and the AQ Coffee/Diamond were compared using the Crane Song Avocet (with Quantum DAC update).

Starting with the Canare AES cable, I connected the the AES out of the PUC2 to my Crane Song Avocet DAC. From the the Crane Song Avocet, I went into Lipinski Sound speakers with amps. Using the same track (Paul Simon, Proof), I began listening. After familiarizing myself with the sound, I quickly swapped the Canare AES/EBU for the AQ Coffee AES/EBU.

I was stunned by the differences, and so was my colleague (a seasoned mastering engineer). Just as I heard when using the Coffee USB, the AES cable provided a clarity and distinction to the many layered tracks of this Paul Simon mix. Bass was tighter, better defined, more robust. Middle and high frequencies also benefited from greater clarity while still being balanced yet distinct. The stereo arc allowed height information to be easily perceived and not exaggerated. Swapping back the Canare AES cable made it apparent that the sound was now congested, or squeezed sounding.

Audioquest Diamond AES/EBU

When replacing the Coffee AES/EBU for the 100% Perfect Surface Silver Diamond, the height information became even more distinct. That arc (in the stereo field) I spoke of earlier was even more pronounced than on the Coffee AES/EBU. Extreme clarity and low background noise was obvious, but Paul Simon’s voice appears to be physically higher in the center image. When testing this AES/EBU cable in my home system I noticed the same phenomena.

The Audioquest USB and AES/EBU cables offered a clear improvement that was easily heard. While the Carbon and Coffee were my favorite designs, even the entry level USB cables from AQ provided a clear balanced presentation without any harshness.

-Happy Listening!

 

Benchmark’s AHB2 Stereo Amplifier

Achieving the full performance/responsiveness out of my speakers has motivated me to examine various amplifiers designs lately. In this quest to squeeze the last sound molecules from my speaker drivers, I have been comparing class A, Class A/B, Class D, and now this hybrid Class H and AB design from Benchmark and THX.

Delivering clean power with an exceptionally low noise floor are the key ingredients to Benchmark’s new Amplifier. The AHB2 is a 2 channel audio amplifier with 100 watts of power into 8 ohms, and 190 into 4 ohms(bridged mono mode 380 watts/8ohms). This super quiet amplifier topology allows for a signal-to-noise ration of 130dB unweighted. The distortion is also quite low, at 0.00011% THD in stereo mode.

With a clean and tidy footprint, The front panel allows access to 1 power button, and several LEDs that indicate proper operation. Benchmark built into the AHB2- a power supply fault protection to monitor voltage, current, and temperature. If issues arise, the fault circuit mutes both channels to protect the amplifier and speakers. The clip lights will illuminate when occasional clipping is present (something that never happened for me), and the fault protection kicks in when severe overdrive occurs- to protect speakers.

On the business end of things, connectivity is straight forward. Other than the addition of Speakon connectors, the Balanced XLR inputs and speaker terminals are standard. One dip switch on the right controls mono or stereo operation, while the 3 position switch on the left controls input sensitivity – a welcome feature. Matching the input sensitivity allowed me to optimize the Gain control between the Crane Song Avocet and the AHB2.

Technically speaking, the AHB2’s Vanishingly low noise floor can be compared to the dynamic capabilities of a 22-bit digital system. Most current professional and audiophile DACS can also achieve very low noise floors – a match made in audiophile heaven.

I used the Crane song Avocet and several other DACs to feed Balanced stereo program material to the AHB2. For speakers I used my Green Mountain Eos HX 2-way speakers. All cabling was balanced solid core copper.

The tidy AHB2 Amp runs cool

I gave the Benchmark amplifier some time to warm-up and have had it in my system for several weeks. My initial reaction was in the form of a grin, as I heard my music amplified in a clear and coherent manner. The extremely low noise floor became revealed as orchestras truly faded to the acoustic space and black was truly black – no residual noise whatsoever from speaker drivers. Even more obvious was a clarity to the amplification. This amplifier runs like a high-performance sports car. I was amazed at the AHB2’s ability to keep up with dense music mixes and never sound congested or lacking. In fact, this tidy beast produced some of the tightest low end I’ve ever heard in my 2 way speakers. The midrange was articulate and clear with an obvious clarity that bested my current class A/B amplifier. Extending to the high frequencies were equally clear and distortion free, no hype here- just honest clean reproduction.

Listening to Beck’s “Morning Phase” (24/96) was ear opening and lovely on the AHB2. The track “Morning” enters with  acoustic guitar strumming and stereo vocals, and leads into lovely strings with reverberant stereo space all around. Even with this wash of sounds, the hit of the Floor tom, or the crisp full fleshed out sound of the snare was colorless and clearly projected.

The Royal Liverpool Philharmonic’s performing Hovhaness’ Mysterious Mountains (Telarc 16/44.1) was sublime. Mount St. Helens Andante, Grazioso unfolds gracefully and with tip top double bass walking the piece along. The bass holds true and rings out even as the full strings come into glide the momentum along. The expansiveness of this orchestral recording is deep and wide with excellent localization. Acoustically, the AHB2 performs so cleanly and quietly that it resolves the hall and space between musicians distinctly- something professional engineers and audiophiles can equally appreciate.

The Benchmark amplifier allowed for dense music mixes to be fully appreciated. Micro-dynamic detail was never lost or distorted, even as complex passages competed. Orchestral and Popular music mixes equally excelled on the AHB2 with authority, control, and balanced sonic presentation. If you are looking for an amplifier that can reveal your source material and DAC without flinching, then the AHB2 is a top choice.

Happy Listening,

HiFiQC

Photography: Vahan Baladouni

 

Crane Song Debuts Avocet IIA with Quantum DAC at AES 139

Crane Song Avocet IIA with Quantum DAC

While I was making my way through the exhibition floor at AES139, I ran into owner/designer, David Hill of Crane Song Electronics. I have been a user and big fan of Mr. Hill’s designs and today I was in for a treat. The Avocet monitor controller had undergone some upgrades and David Hill was excited to tell me about it. I was first treated to a comparison of the upgraded DAC, and then we shot a short video describing the various updates to the Avocet IIA Quantum DAC.

My first video for HiFIQC

Stranded Copper Wire vs. Solid Core Copper Audio Wire

The way audio cables are constructed can certainly make a difference to their sonic characteristics. Over the past several years I have been comparing the sound transmission characteristics of different copper conductors. In addition to the conductors, different geometries, dielectric material, and shielding can make a cable sound different. While these can influence the sound, I feel the primary sonic impressions I have been hearing have to do with the interaction of conductors carrying an audio signal. Stay tuned for a full write-up on stranded copper vs solid core copper audio wire.

EQ Your World with “Here Active Listening”

Doppler Labs just raised $17 million to produce a wearable bionic hearing device. Here Active Listening is being dubbed the first true “hearable tech.” These are not earbuds for listening to music, but rather a kind of bionic hearing device for engaging with real world sounds around you. By using two ear buds with microphones and internal processing, an individual user can curate his/her own listening experience in various acoustic environments (with the aid of a smartphone app). Noisy environment, bad mix at a live concert- any situation where you are engaging with real-world sounds.

Here, Hans Zimmer (film composer) discusses the future of sound and how wearables may change our perception of sounds around us:

Sonic Water

Sonic Water

What does sound look like? Visualizing the dispersion of sound waves has always fascinated me. Compression and rarefaction of air molecules create the sensation of hearing all around us, yet it is invisible to the human eye. Cymatics, or a way of visualizing sound through matter (i.e. sand or water) allows another glimpse into the complex dispersion characteristics of sound pressure and frequency.

A recent installation at the Olympus Photography Playground in Berlin uses a speaker with a bottle cap of water resting on top. By using special lighting, a clear visualization of the water patterns (created by Synthesizers which in turn create sound transmission/vibrations on the speaker cone) can be witnessed. Watch this video below for an example of this interactive exhibit.

For more information on Sonic Water visit the Laboratory for Water Sound Images.

The HiFiQC Method For Stereo Microphone Isolation

ORTF with UMS 20 Stereo Bar mounted to Rycote Lyre suspension

Recording music and sound effects with carefully placed stereo microphones can present some challenges. Since directional microphones are more sensitive to infrasonic noise, special attention should be taken when placing them in various environments. Wind, machines, automobile traffic, and footsteps can all cause rumble or noise to build-up and eventually reach your microphones. The low-frequency nature of these sounds can take up precious headroom in your audio recordings. While wind (blowing on the capsules) can be tamed with various foam enclosures (the W5D is my favorite for Schoeps) don’t forget to isolate mechanical vibrations from reaching your mics too. After trying elastic shockmounts alone, I devised 3-part system to better isolate my ORTF stereo array (also works for MS, XY, and Blumlein) from infrasonic disturbances .

A 3/8 inch mic mount threading adapter allows me to eliminate the 20 mm Schoeps mounting adapter, saving 38 grams of weight

To start, Rycote has a non-elastic suspension made of a super-strong thermoplastic called Hytrel. And unlike elastic, it won’t sag and eventually wear-out (so far, so good). After being impressed with a Rycote Invision suspension for a single Schoeps mic, I decided to see if a solution existed for isolating 2 Schoeps mics arranged on the UMS 20 stereo bar.

After some digging, I came across the Rycote portable recorder suspension and wondered if it might work since the weight of the stereo bar and mics was nearly identical to most portable recorders. As you can see from the picture above, this model easily supports and isolates the Schoeps universal stereo bracket with mics attached.

Carbon Fiber Disc and Sorbothane Hemisphere

Using a microphone suspension is certainly one method to help prevent vibrations from reaching your mics, but what about infrasonic born vibration from foot traffic, cars nearby, or HVAC compressors. These disturbances can travel up your mic stand and into your microphone.

After experiencing issues from foot steps and traffic rumble, I worked on a solution to isolate the microphone tripod from the ground itself. Both Carbon Fiber and Sorbothane are materials known to dissipate mechanical energy. So, I settled on Sorbothane hemispheres attached to an equal diameter carbon fiber disc.  Sorbothane works best when compressed under a range of weight (depending on size and Duro rating of hemisphere). By choosing a durometer rating of 50 in the 1.5″x.75″ Sorbothane hemisphere, 7-14 pounds of weight on each tripod leg could be isolated.  And after adding some 8 lbs sand bags to my tripod, I was able to get the load heavy enough to make the Sorbothane hemishpere’s truly effective.

Sorbothane being compressed by the weight of microphone stand and sandbags

Lastly, but equally important is making sure your microphone cables do not transmit cable-borne noise to the microphone body. Carefully dressing your mic cables around the tripod is essential to preventing vibrations from reaching your mic. With the help of velcro cable wraps, you can neatly run your mic cables, but don’t forget to pay attention to where and how they are laid on the ground. In some cases you may need to isolate the cable on the ground too.

For those looking for an even smaller stereo mic setup with windjammer possibilities…Check out this ORTF setup with Schoeps CCM mics, Rycote Lyre suspension, and even a Rycote connobox to eliminate cable handling noise!

Happy Recording,

-HiFiQC