Benchmark Media Systems DAC2 HGC

Device Type: Digital to Analog Converter/Preamplifier/Headphone Amplifier
Digital Inputs: Asynchronous USB Audio Class 2.0 : Up to 24bit, 44.1, 48, 88.2, 96, 176.4, 192 kHz; DSD 64 ; Two Coaxial that support 24-bits and sample rates between 28-195kHz, and native DSD 64, Two Optical that support up to 24/96
Output: 2 Pair RCA (Unbalanced) and 1 Pair XLR Balanced
Analog Audio Inputs: 2 RCA Stereo Pair (Unbalanced RCA)
Dimensions (H x W x D): 1.725 inches X 9.5 inches X 8.5 inches
Weight: 3 pounds
Availability: Authorized Dealers
Price: $1,995.00

The Benchmark Media Systems DAC2 HGC represents Benchmark’s most advanced and feature laden DAC offering. Despite its diminutive size, the DAC2 HGC is a full featured DAC with an asynchronous USB input that supports PCM up to 24/192 and native DSD 64 using the DoP 1.1 format. A remote controlled preamp is included with Benchmark’s Hybrid Gain Control system that utilizes a servo-driven volume control and 2 headphone jacks with a switch that automatically mutes the XLR and RCA outputs when using the headphone amplifier. A metal remote is included that controls the power, volume, polarity, input selection, mute, and dim controls of the DAC. Other features include a 12V Trigger I/O and Home Theatre Bypass.

The Design
The heart of the DAC2 HGC is based on 4 balanced ESS Sabre 32-bit D/A converters per channel. Benchmark feels that this 4:1 redundancy reduces noise and distortion to extremely low levels; certainly the best that Benchmark has yet achieved in their DAC designs.

The UltraLock2 system employs 32-bit DSP processing that results in decreased jitter-induced distortion and noise by at least 160db below the level of the music according to Benchmark. This digital processing in the DAC2 HGC is designed to handle signals as high as +3.5 dBFS. This extra headroom over the 0 dBFS limitation found in other DACs results in less harshness or emphasis of the highs that results from broadband distortion products produced from clipping.

The UltraLock2 system upsamples to a sample rate of 211kHz. I asked John Siau, designer of the DAC2 HGC, how his UltraLock2 system worked:

“PCM inputs are upsampled to 211 kHz. This upsampling is part of Benchmark's UltraLock2 jitter-attenuation system. This system removes all traces of jitter while improving the image-rejection of the D/A converter. Jitter-attenuation is very important when using coaxial and optical inputs. The upsampling is very transparent because we maintain 3.5 dB of headroom above 0 dBFS to handle inter-sample overs. Most upsampling systems will clip inter-sample overs, but Benchmark's UltraLock2 system will not clip. Upsampling can be a mathematically-transparent process if enough processing power and headroom is dedicated to the process. The Benchmark upsampler uses a high bit-depth to essentially eliminate the round-off errors that many upsamplers produce. The result is a clean distortion-free spectrum without any jitter-induced distortion.”
I also asked John how the DAC2 HGS isolates computer noise (common mode and HF) on the USB line.
“The USB subsystem is isolated from the D/A conversion subsystem. Dedicated fixed frequency crystal oscillators pull data from the computer and then pass data to the Benchmark UltraLock2 system. The D/A conversion clock is entirely independent from the USB clocks. The UltraLock2 system passes data between the two independent asynchronous clock domains. The clock domains even have independent voltage regulators. Like many of today's USB interfaces, data transfer between the computer and USB subsystem is asynchronous. Benchmark takes this a step further by using asynchronous data transfer between the USB subsystem and the D/A conversion subsystem.”

Native DSD Conversion
Native DSD 64 conversion can be delivered to the USB or Coaxial inputs in DoP 1.1 format. The DSD signal is then routed directly to the ESS Sabre 1-bit DSD D/A converters. John told me that up-conversion is not applied to DSD files:

“The up-conversion applies to PCM only. DSD conversion is at the native sample rate. DSD is not converted to PCM.”
The Hybrid Gain Control
"HGC" is Benchmark's Hybrid Gain Control system. This system combines a 32–bit digital gain control with an active analog gain control that has passive low-impedance attenuators. The servo-driven rotary volume control can be controlled with the remote. The analog inputs are never converted to digital and the digital inputs that are controlled in the 32-bit DSP system never pass through the analog potentiometer.

The HPA2 Headphone Amplifier
The headphone outputs are driven by a high-current, high-output amplifier that has an output impedance of near 0-Ohms. This amp is designed to drive loads as low as 30 Ohms without any increase in distortion. Benchmark has designed this headphone amplifier with the capability to handle low-sensitivity 600-Ohm headphones.

The Front Panel
The DAC2-HGC is available in a silver or black aluminum panel. There are a series of LEDs that indicate 16 or 24 bit files. Other LED indicators, singly or in combination, light to indicate the sample rate or DSD playback. The input status of the 7 inputs is also indicated by the LEDs.

Internal Settings
The XLR outputs have low-impedance passive pads that can be used to reduce the output levels of the DAC2 that allow optimum pairing with power amps and preservation of the full dynamic range of the DAC2. The factory default is the 10 dB pad setting. 0 dB and 20 dB settings are also available. Headphone Gain Range Adjustment, Headphone Switch Disable (analog inputs mute when a headphone plug is inserted into the left-hand jack), and Digital Pass Though Enable can be set with the internal jumpers.

For those of you that desire a more complete discussion of the DAC2-HGC’s functions and technical features, I suggest that you read the manual that is shipped with the DAC. This informative manual can also be downloaded from the Benchmark site. This is the most complete manual I have yet seen for any DAC and it also includes 16 pages of performance graphs for the DAC2 HGC (download the DAC2 manual).

Components and Software Used In This Review
OSX Mavericks 10.9 was recently released by Apple that restored a significant feature previously lost in OSX 10.7 and 10.8; non mixable integer stream format capability. Pure Music, Audirvana Plus, and JRiver 19 for OSX have integer capability if this feature is supported by the DAC. I was happy to find that the Benchmark supported native integer playback using the native OSX USB drivers. Benchmark supplies Windows drivers for support of USB Audio Class 2.

I had the best sonic results with Audirvana Plus with my system and the DAC2 HGC. The other two players were a little bright sounding with this DAC but still quite good. I selected Integer in setup but not Direct Mode.

Computer Used: MacBook Pro 2.3 GHz Quad Core i7, 16 GB RAM, Samsung 840 Pro SSD, Boot Camp Windows 8.1 Pro 64, Promise Pegasus Thunderbolt Drive 8TB, GRAID 8TB Thunderbolt Drives. For USB cables, my best results were had with both the Audioquest Diamond and Synergistic Research Active SE cables. AC cables used with The Benchmark were the standard AC cable supplied as well as the JPS Labs Digital AC-X AC cord. 2 Synergistic Research Tranquility Bases and Thunderbolt Active SE cables all driven by the Transporter Ultra SE. Power conditioning was provided by the Synergistic Research PowerCell 10 SE MK III.

Interconnects used with the DAC 2 HGC were the Synergistic Research Tesla Apex LE and the Audioquest Sky.

Sonic Impressions
The Benchmark DAC2 HGC is sonically as neutral a DAC as I have ever heard. It borders on a somewhat light sonic texture with absolutely no digital hardness or extreme brightness. The sound is quite detailed and well defined with no warmth or added richness. One attribute of the DAC2 HGC I enjoyed was its very well defined and articulated bass. At first, I thought the DAC2 HGC was somewhat light in the bottom 2 octaves, but with a modest tweak of gain on my Wilson Watch Dog sub, everything fell into place. The low end had good impact and did a good job of reproducing dynamic contrasts. The soundstage displayed reasonable width and front-to-back depth.

I am used to a bit more sonic weight with DACs like my reference Wavelength Crimson / Denominator and the MSB Technology Analog DAC with Analog Power Base, but I quickly acclimated to the Benchmark’s sonic characteristics and found this DAC to be quite enjoyable to listen to.

Playing Jane Monheit’s The Heart of the Matter 24/88.2 (HDtracks) I found that the Benchmark DAC 2 HGC did a fine job of focusing Jane Monheit’s voice in the studio soundstage with exceptional clarity. This is a wonderful recording with Jane’s voice highlighted with a slightly up-front presentation. The interplay of the strings, flute, guitar and voice were beautifully reproduced by the Benchmark in the song "When She Loved Me". Each of the instruments were reproduced in their own acoustic space with no blurring of Jane’s voice.

Jimmy Webb’s Still Within The Sound Of My Voice 24/44.1 (HDtracks) also benefited from the light, quick sound of the Benchmark. The guitar and mandolin were beautifully reproduced with a sense of realism that many DACs fail to capture. The Benchmark drew me into the music and never seemed to be lacking in focus of definition. The DAC 2 HGC was able to capture the subtle string sounds in a relaxed manner without over emphasis or digital artifacts.

A fine example of what the Benchmark DAC2 HGC can do when it comes to reproduction of the sonic space of a recording was with the Chesky Binaural+ release C.C. Coletti Bring It On Home 24/192 (HDtracks). This recording captures the acoustic space of the room with a deep and wide sonic presentation of the vocals, guitar and percussion. C.C. Coletti’s blues vocals were floated in this acoustic space with excellent focus as were the accompanying instruments. The Benachmark DAC 2 HGC was able to reproduce the three dimensional feel of the acoustic space on this recording.

Native DSD Playback
What I enjoyed most about the Benchmark DAC2 HGC was the way it handled native DSD files. DSD playback added richness to the sound with additional midrange weight that added realism to the reproduced music.

If you want to try some DSD files from Acoustic Sounds, I would check out the Nat King Cole title The Very Thought of You. I loved the LP from DCC Compact Classics, and I’m happy to say that the Analogue Productions release is equally beautiful if not even a little better sounding. The voice is closely miked, but extremely natural sounding and never sounds over-loaded. The soundstage is wide with the strings emerging from the background.

Also from Acoustic Sounds is Rickie Lee Jones Traffic From Paradise. This title is no less impressive than the Nat “King” Cole title. I played "Stewart’s Coat" and delighted in another wide sonic presentation with instruments and voices well delineated. The relaxed natural sound of this recording came through on the DAC2 HGC.

The Tilson Thomas / San Francisco Symphony Mahler Symphony No. 4 from Blue Coast Records was also handled very well by the DAC2 HGC. This .dsf title was rendered with a large soundstage with good depth. The string sound was liquid and beautifully defined. The dynamics of the orchestra were well handled by the Benchmark with no signs of overload or hardness. This DSD recording will serve as a reference recording for me in the future and is highly recommended.

The Hybrid Gain Control
The Benchmark DAC2 HGC’s volume control did a capable job driving my Ayre MX-R amps. Given the internal adjustments previously discussed, one can achieve output with the optimum setting of the volume control. The remote control feature is very well designed and responsive in function. I did prefer playing the DAC2 HGC through my Ayre KX-R preamp and felt the sound of the KX-R was superior. But, after all, the KX-R is $18,500. I believe that if the DAC2 HGC is combined with something like the new Benchmark AHB2 power amp, one would have a high performance setup at a reasonable price that would negate the need for an additional preamp component.

The Headphone Amplifier
I listened to the DAC2 HGC’s headphone amplifier with a pair of Sennheiser HD 600 headphones. Returning to the Chesky Binaural+ C.C. Coletti recording, the DAC2 HGC easily drove this headphone. Listening to this Binaural+ title was a real treat and certainly presented a large acoustic space as previously heard when played through my Ayre / Wilson system.

A Sonic Upgrade for the DAC2 HGC
While the standard AC cord that comes with DAC2 HGC works well, I tried the JPS Labs Digital AC-X Power Cord ($400). The AC-X is especially designed for digital components and will be reviewed in the near future. The AC-X made a substantial improvement to the DAC2 HGC’s sound compared to the stock AC cord supplied with the DAC.

A DAC that Delivers the Goods
This is the first DAC I have reviewed for AudioStream that is priced under $6,000. While my initial expectations were not great, I was surprised at the level of sonic and functional performance offered by the DAC2 HGC. The DAC2 HGC was a pleasure to listen to with PCM and especially with native DSD files. Its acoustic honesty and functional precision was easily observed and appreciated. No doubt, John Siau and his team have designed a DAC that does not have to make any apologies to DACs costing considerably more. At its price of $1,995, I consider the DAC2 HGC to be a solid value.

Associated Equipment

moosehunt's picture

Thank you for the review! I currently use a Dac1 USB / Musical Fidelity V-Link 192 combo, and would love to know if anybody has compared the new Bechmark to its predecessor? Is the sound in general (and the USB implementation in particular) improved different? Simply upgrading for the DSD playback probably isn't worth it, but that coupled with upgraded sound / USB would be? Look forward to what people have to say. 

velociti's picture reviewed it earlier this year, and the reviewer compared both. Having heard the DAC2, it's a clear improvement on the DAC1. Significantly more neutral, and a bit more resolving, as well. 

wgb113's picture

I guess it depends on the level of you gear.  I couldn't tell a difference with my active Dynaudios or my KEF LS50 + Parasound Halo A23 when playing back 16/44 CD rips or 24/96 downloads.  My DAC1 USB never seemed to impart a sound on anything and the DAC2 HGC was no different in that respect with my gear.

I did like the remote functionality but the loss of the -30dB pads made toning down the level on the balanced outputs so that they'd be close to the unbalanced outs made it difficult for me to integrate a sub.  I ended up returning the DAC2 HGC.

Benchmark's included headphone amp was always among the best sounding to me as well, again by not imparting a sound of it's own and being able to drive any headphone load thrown at it.


handler's picture

Hi Bill,

I'm interested in this DAC 2 HDC, but am concerned with what you experienced. I too would use XLR on my amps and RCA on my sub. Due to the different gains, does one output not "increase" or "track" the volume at the same rate as the other?

- Ryan

wgb113's picture


It's not that it doesn't "track" up and down with manipulation of the volume control, it's just that you can't get the XLR output low enough with the jumper pad settings at -20dB to even closely match the unbalanced outputs.  With the DAC1 USB's -30dB jumper setting it was much closer, especially when I could further attenuate on the Dynaudios.  That 10dB made all the difference in my system and in the end was a dealbreaker.  Other than that the DAC2 HGC was a keeper in every other respect.


wgb113's picture


Acoustic Sounds just released a DSD version of the newly remastered Kind Of Blue.  Any chance we could get a comparison with the hi-rez PCM versions through the Benchmark?



Steven Plaskin's picture

Hi Bill,

The DAC 2 HGC was returned today. I have the 24/192 stereo version, but not the DSD.

I think I will keep the next DAC for a week after publishing the review to answer questions like yours.

JR_Audio's picture

I am strongly missing the comparison of the Benchmark DAC2 HGC against other Greatest Bits DACs in the similar price range to answer for example the question, is it worth the bit higher price compared to the Mytek Stereo192-DSD DAC. Michael Lavorgna does make those comparisons in many of his reviews. So is there a plan, that Michael will audition this DAC too (as a follow up)?


handjar rukmana's picture

Hi Steve,

Would you recommend using Sony HAP-Z1 ES media player with Benchmark dac2 since i already have one and run it as preamp to my Cary Cad 805 AE ?

DSD quallity sound is what i`m trying to get. 

Thanks Steve...

Steven Plaskin's picture

Hey handjar,

To the best of my knowledge, the Sony HAP-Z1 ES media player is not connected to an external DAC, but has outputs that are connected to your amp. The USB output on the back is for more music file stroage over the 1TB limit of the unit.