Channel Islands E•200S Stereo Amplifier

img_3434

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.

img_3433

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 ConvenienceThis 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.

4f590fe9-50c0-4e22-b43a-654119fe02f3-1

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

Benchmark’s AHB2 Stereo Amplifier

DSC00383

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.

DSC00387

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.

DSC00408

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

 

`

FrankAHB2

Frank reveals the Benchmark Media AHB2 Audio Amplifier:

Read the full review here

For the past couple weeks I’ve been auditioning the Benchmark Media AHB2 amplifier, and will be featuring a full review soon. Inside the tidy footprint and magnetically shielded casework of the AHB2 are a host of unique advances in audio amplifier design….and boy is it quiet!

Stay Tuned -HiFiQC

Channel Islands Audio D-500 MK II Monoblock Amplifiers

CIAudio1

Audio power amplifiers provide the juice or alternating current for our speakers to move in and out, creating positive and negative pressure (Sound). This electromagnetic induction
relies on the marriage of speaker drivers, cabinets, crossovers, and, of course amplifiers. While various amplifier topologies exist, designing one that accurately portrays music can be a challenge. Channel Islands Audio, has been cooking up high-quality audio designs for over 18 years, and I recently had the opportunity to audition a pair of their 500 watt monoblock amplifiers. The Channel Islands Audio D500 MKII mono block power amplifiers currently in their 2nd iteration have been powering my system for a couple months now.

CIAudio2*

The Class D design of this audio amplifier allows it to run very efficiently. In fact, they run cool to the touch. I can recall many class A amplifiers that raised the room temperature by several degrees, add a room full of studio equipment and you get a hot and sweaty audio engineer- no fun.

CIAudio2

Each amplifier and massive power supply is housed in a separate steel frame and aluminium chassis. Don’t think you have room for monoblock amps? With a height of 4 inches and a tidy footprint of just 8.5 wide by 13.5 inches deep, these amps will tuck away more easily than you think. The casework is tight fitting aluminium with non-magnetic steel hardware and an On/Off push button with a blue LED surround.

Screen Shot 2015-11-26 at 6.17.30 AM

Rear XLR or unbalanced RCA inputs, speaker binding posts, trigger, AC

Moving to the business end, the D500 MK II provides XLR or RCA line-level inputs, 5-way speaker binding posts, trigger inputs, and an IEC power inlet. For my listening, I connected to each amplifier via balanced XLR connectors from my monitor controller. I used a pair of 2-way (1st order xover) speakers for listening and a well designed room at a hollywood mastering studio. As far as after market power cables go, we found these amps sounded best/most balanced with the cord supplied (i.e. nothing fancy).

After warm up, we fed a variety of studio quality masters through these monoblock amplifiers. I started with a favorite, Muddy Waters Folk Singer. In this hard panned early stereo recording very distinct tracks of guitar, vocal, bass, and drums can be easily distinguished. A great recording true, but the dynamics of the vocal really stress the ability of amp and speakers to communicate the space (echochamber at chess records) and impact of this album. The CI Audio amps did not let me down. Not only was the control over the music’s dynamic fluctuations handled well, but they did so with ease and lightning fast response. Hearing the space around the music is important for feeling an honest connection to the performance. No where is it so obvious as with Mumtaz Muhal, a stereo recording done in a chapel with three musicians. This recording features Taj Mahal performing songs like Stand By Me with Indian classical instrument accompaniment. The Mohan Vina, a slide-like sitar follows the vocal massaging of Taj Mahal like a second voice gently ascending. The natural space of this recording is preserved and replayed over the CI Audio monoblocks with all the emotional connection and tone intact.

Playing back a 24/96 transfer of Stevie Wonder Songs in the Key of Life showed how these little beasts grip your speakers and provide extended tight bass. Listening to the track I Wish showed off these amps ability to clearly portray all the tracks in this loaded mix. A wide and appropriately deep soundstage was achieved using the D500 MK II amplifiers. Even when the overall sonic energy of a song’s mix was full, these amplifiers reproduced clearly and without any strain. Side Note: I’ve been playing these amps for over 8 hours and they are cool to the touch!

Listening to full orchestral pieces from Beethoven’s 9th symphony truly showed off these mono block amplifiers ability to further handle complex and dense musical passages. The quietest passages arose from a black background and when the double bass stepped in, it did so with stride and control usually unheard  in my small speakers. Through the roll of the timpani and onward, the full orchestra was handled with an even and accurate tone. Localization of instruments was obvious and portrayed the stereo microphone technique clearly.

For a wider variety of instruments and sounds I pulled out Beck’s Sea Change and Tom Wait’s Swordfishtrombones. Reproducing the raspy voice of Waits or the somber melancholy stylings of Beck, The D500’s were true to all the fleshy midrange detail. Moving up the frequency range, even the extended response of cymbals was smooth and never overly bright or etched.

While we did not have other speakers to directly power from the CI Audio amp, we did have several other systems in place for monitoring audio. The Lipinski Sound amps and speakers were compared to the Channel Islands Audio amps and GMA Eos HX speakers. Myself and other engineers concluded that the sound of each system were both resolving and usable. The Channel Islands D500 MK II proved to be a clear musical amplifier with a place in the audiophile as well as professional markets. Happy Listening!

Channel Islands D500 MK II Specs:

Power Output 500 watts @ 8 ohms/800 watts @ 4 ohms Bandwidth 50kHz

Frequency Response10Hz – 20kHz, +0dB/-0.5dB

Damping Factor>1000Input Impedance100k ohms Gain 38db or 32db

Dimensions 8.5″w x 4.0″h x 13.5″d

Weight 28 lbs (each)

Warranty 5 Year Parts & Labor

Associated Equipment: Crane Song Avocet, SADIE, Lipinski Sound, GMA Eos HX

Green Amplifier Technology Comes of Age

Image

This is the "Greenest" thing I have.

Power Amplifiers for Hi-Fi stereo systems come in a variety of types. Audiophiles often prefer tube or solid state amps, while some like hybrid amp designs.  Having used both tube and solid-state amplifier designs has given me an appreciation for both approaches. Class A, AB solid state*, and tube designs are often the most used amps for high end music playback. I’ll admit that tube amp designs can impart a beautiful tonality on the music, but sometimes the added harmonic content is too much for my tastes.

Although Class D (pulse width modulation) amps have been around since the mid 70’s, they have been mostly used in consumer grade electronics and live sound installations. Many of the home theatre-in-a-box and recent iPod sound docks** also use Class D amplifier technology.

Being energy-efficient, physically small, and running cool makes class D amps very attractive to the consumer market. High end audio companies also took notice. Companies like Lipinski, Bel Canto, NuForce, Wyred for Sound and CI Audio have all worked at making the most musically satisfying class D designs.  The ability to drive most speaker loads and exert extreme control over the speaker drivers make class D very attractive indeed.***

Sonically, I have experienced mixed results with audiophile class D amps. While quiet, fast, and revealing, they can also sound a bit dry or stark. Comparing these current generation class D amps to Class A and AB designs has kept me from recommending any one class D amp for audiophiles.

The Dutch Masters?

A small company in The Netherlands, Hypex, has taken control of the current class D amplifier scene. Hypex  builds many OEM Class D subassemblies that make their way into audiophile amps. A new generation of this Class D amplifier called Ncore is supposed to “surpass the best linear amplifiers – in every way,” according to Hypex. Luckily, 6moons (audio review site) had a chance to try these new modules and speak with the designers. You can read the full article here.

  1. * Audio Amplifier designs explained here.
  2. **Hypex is also known for designing the Class D amp and power supply found in the Bower &Wilkins Zeppelin iPod dock.
  3. ***This is refered to as the Damping Factor of an audio amplifier.