Crane Song Avocet with Quantum DAC

QuantumDAC

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!

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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. remoteThe 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!

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Benchmark’s AHB2 Stereo Amplifier

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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.

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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.

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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

 

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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

Morning Phase by Beck and Quality Control

Beck's New Album Morning Phase

Beck’s New Album Morning Phase

Beck Hansen’s new album is said to be a sequel to Sea Change (2002). Released at the end of February 2014, Morning Phase brings the confessional and  slowly building song style that first appeared on the Sea Change album.

It certainly follows in the same instrumentation and song writing style of Sea Change, but I also noticed a bit more Country or Americana influences on Beck’s latest offering. Pulling you in slowly but steadily, this gentle album is masterfully constructed and begs to be listened to from start to end.

I would like to tip my hat to Michael Lavorgna over at Audiostream for investigating the HD Tracks 24/96 version of Morning Phase. You can read more about it here.

This brings up a couple of points. Firstly, releasing an album in 24 bits with heavy limiting and compression just doesn’t make much sense. This is mainly because the available dynamic range is not being used. Also noted was that many of the tracks were upsampled from 48Khz to 96Khz SR.

I understand that Beck and other artists presumably choose to release their albums with the sonic signature that they feel represents the style and sound they want. It just makes me wonder if the artists, producers, and engineers enjoy the distorted artifacts that heavy limiting produces.

There is a device called a Distressor (Emperical Labs) that is used to produce a compressed and harmonically related sound while mixing drums and other instruments. This type of sonic coloring is a choice and can be used in a very musical way. On the other hand, artifacts introduced by digital limiting are harsh and in my opinion sonically unrelated to the fundamental note.

While I have yet to hear the vinyl, consensus is that it is the superior format. Records must be mastered differently and for physical limitations of the medium (Vinyl) cannot be compressed or limited like a digital format. Anyone heard the vinyl of this yet?

Always Listening,

-HiFiQC

Listening to the Hegel HD20 DAC…and Beyond

Hegel HD20 DAC from Norway

Hegel HD20 DAC from Norway

Digital-to-analog converters have come a long way, and it seems like there is no end in sight. Precise timing of the samples in a digital stream of audio can make the difference between music being reproduced naturally or with some haze and artifacts. And like many DACs the Hegel HD 20 reclocks the incoming signal for the lowest possible jitter. In addition to this reclocking, Hegel also uses a special imepedance correcting input (coax 1) to ensure the best sound from a standard RCA terminated digital cable.

At first glance this unassuming black box simply has digital inputs and analog outputs on the rear with a simple blue LCD display on front. The power supply is built-in, and a supplied remote controls the input selection and digital volume. The remote may also be used to control your computer if the DAC is connected through USB (which is limited to 96kHz SR). 2 coaxial digital inputs on RCA, one optical input, and one USB input are supplied. Analog outputs come in 2 flavors; single-ended RCA and balanced XLR.

Rear of the Hegel HD20

Rear of the Hegel HD20

In Use: The Hegel’s balanced outputs connected directly into my amplifier as well as my monitor controller for two setups. 1)The direct-to-amp scenario requires using the built-in digital volume, which can leave something to be desired when played at low volume settings. 2)When connected through my class A monitor controller via XLR the sound was tight, smooth and detailed. The space of the stereo image was well-defined and localization of instruments was clear. Funny enough, we found that coax 2 provided this tighter larger stereo image compared to coax 1 (with the impedance correction).

Playing acoustic music through my Green Mountain Audio Eos HX was natural and defined with the HD20. If it has any sound signature, I would say it is relaxed and detailed. Nothing in the mixes I listened to sounded hyped or overly detailed. The beauty of this DAC was its ability to stay organic and 3 dimensional in the home environment.

Using the HD20 with a dedicated headphone amp was may favorite. The sound is spacious, natural….just plain listenable. Many of my favorite Jazz recordings came through my HD-600 headphones with a smoothness that made music listening a treat. Combined with the CI Audio headphone amp, the Hegel truly shined.

Opting for the USB input allowed me access to internet radio and computer audio files. This USB input  is limited to 96kHz SR. While this is certainly a convenient feature, it lacks the full sample rate handling for high-definition downloads..

Other than the coaxial 1 input issues, I was impressed with the large natural sound stage and the organic timbre that the Hegel HD20 was capable of delivering. Now with the introduction of the Hegel HD25, the company has harnessed current 32 bit DAC chipsets, and allowed the full 192Khz SR over the USB input. In addition, the NEW HD25 also allows you to choose between two different digital filters to suit your tastes. While I have not auditioned this new DAC offering, I can certainly say that if the HD20 is any sonic indication, an audition of the new HD25 from Hegel is a must.