Benchmark DAC1 HDR USB DAC and Headphone Amplifier Review

June 10, 2012

With the rise in the dominance of music playback by way of computer, today’s entry-level system can be as minimalist as a laptop, a USB DAC, an integrated amplifier and speakers. You can later add a separate power amplifier, using the preamplifier outputs of the integrated amplifier for source selection and volume control. But why not skip a step and simply purchase a USB DAC with headphone amplifier and a power amplifier in lieu of a DAC and integrated amplifier? It offers a better price/performance proposition. Many DAC/headphone amplifiers have analog outputs on the rear panel, and for those that don’t, as is the case with the Music Hall dac25.3 which I reviewed here, a simple ¼” stereo plug to dual RCA jack adapter can be called into service. Contemplating adding a turntable in the future? There is a least one USB DAC with headphone amplifier and phono stage – the Furutech ADL GT40 – which I reviewed here. Perhaps more versatile would be a DAC/headphone amplifier with an analog input, so you have more phono preamplifier options. Coincidentally, the subject of this review – the Benchmark DAC1 HDR – is just that.

Benchmark requires no introduction to either professional recording engineers or audiophiles. They have led the way in providing DAC/headphone amplifiers for at least a decade. Like many computer audio components, audiophiles have sought out professional products to provide the link to computers. When Benchmark introduced in DAC1 USB in 2007, it was immediately adopted by audiophiles, In 2008, they unveiled the DAC1 PRE which added an analog input and upgraded the internal architecture. The Benchmark DAC1 HDR is its latest, greatest iteration.

Let’s first look at what the DAC1 Pre ($1595) and the DAC1 HDR ($1895) have in common. They share the same small, one-half rack wide, 1U form factor as all models of Benchmark’s DACs (9.33″W x 1.725″H x 9.5″D). Rackmount ears and a rackmount tray are available separately. You have a choice of either a black or silver faceplate. The front and rear panels are identical. On the left front center is a source selection switch to choose from among the analog, USB, optical digital, and three coaxial digital inputs. One of six corresponding blue LED lights up to indicate the source selected. If a digital source is selected but there is nothing connected to it or the DAC cannot achieve lock, the LED will blink. If you have engaged the mute, all LEDs are lit. The source selection switch also serves as a push-button on/off switch. Since it the on/off legend is small and I don’t always read the manual first, it took me a while to figure that out. Two ¼” headphone jacks are right center making headphone comparison or listening with a friend easy. The output of the headphone jacks can be adjusted using internal jumpers to match the sensitivity of your headphones. Plugging headphones into the left jack disables the rear panel output. The knurled analog volume control is on the far right. The Benchmark HDR does not adjust volume in the digital domain.

Around back are an integral IEC power inlet and fuse holder, USB and optical digital inputs, three RCA jacks for coaxial digital input, two RCA jacks for analog input, both balanced XLR and unbalanced RCA analog outputs, and a small toggle switch to select among variable or fixed output or mute. The RCA jacks are gold-plated, Teflon models. The analog outputs can be calibrated using internal, 10-turn trim resistors. I stress the availability of balanced analog outputs. Balanced cables are quieter than unbalanced, especially for the long runs you likely to encounter if your power amplifier is sited near your speakers. Long interconnects and short speakers cables are preferable to short interconnects and long speaker cables from both a price and performance perspective. Given the unit’s slight 3.5 pound weight, you will want to avoid using a heavy, stiff after-market power cord. Speaking of which, the power supply is a linear one, using a low-radiation toroidal transformer rather than the more common internal or external switch-mode power supply. While we are looking around inside, note the state-of-the-art LM4562/LME49860 high-current, low-distortion op-amps used in the analog circuits.

What are the differences between the Benchmark DAC1 PRE and the DAC1 HDR? Simple: remote control of all functions. The Benchmark DAC1 HDR is equipped with a motorized Alps volume control. The volume control is a little stiff still when turning it manually. I would much rather have a stiff than a loose volume control, so I see that as a benefit. One of the neat things is that when you mute the DAC using the remote, it does not simply engage a mute circuit or disconnect the input; instead, it physically turns the volume control down. When you un-mute it, it physically turns the volume control back up to where it was before you muted it. It is a little thing, but it makes the DAC1 HDR that much more pleasurable to use. A separate button “dims” the unit, which is like mute, except that the volume to lowered to a user-set level rather than turned all the way down. In addition to controlling volume and mute, the remote also turns the unit on and off, and controls source selection

For testing purposes, to take advantage of all of its inputs, I connected the Benchmark HDR to my Mac Mini with 16GB of RAM and running Pure Music playback software via a Wireworld Starlight USB cable, a Halide Design Bridge USB to S/PDIF converter, and a standard to mini-Toslink optical cable of unknown provenance. That gave me connection by adaptive (USB) and asynchronous (Halide Design) interface, and well as S/PDIF (optical). Cycling through the inputs, I was unable to detect any audible differences. Perhaps on a more resolving system. My advice is to connect the Benchmark HDR to your computer using whatever method is most convenient. In most cases, that would be USB, so that is how I listened to it. It is important to note, that while the Benchmark HDR can operate at up to 192/24 using its coaxial S/PDIF connection, like the Halide Design Bridge, connection by USB is limited to 96/24. I do not think the lack of 192/24 USB capability, given the extremely limited catalog and dubious sonic superiority, is a limitation to worry over. The Toslink connection is also limited to 96/24 by virtue of the limited bandwidth of its interface.

As I alluded to above, the USB interface of the Benchmark is adaptive, meaning that the clock in the computer controls the transmission of the digital bits. The trend in USB DAC design has been toward an asynchronous connection where the clock in the DAC controls the transmission of data. This topology tends toward lower jitter. However, as we learned in my interview of the designer of the Halide Design Bridge here, ultimate performance rests in the implementation. Benchmark claims that its interface implementation, where the DAC clock is isolated from the input digital audio clock, no jitter-induced artifacts can be detected using an Audio Precision System 2 Cascade test set. John Atkinson has measured the jitter of the Benchmark DAC1 USB, which uses the same topology as the DAC1 HDR, with a Miller Analyzer, and recorded 157 picoseconds of peak to peak jitter, which is excellent performance.

To verify that The Benchmark HDR would pass a 96/24 audio stream over its USB input, I cued up the 96/24 version of The Eagles’ Hotel California I downloaded from HDtracks (you can see the spectral analysis compared to CD here); it should come as no surprise that it played perfectly. I skipped the title cut as I have heard it so many times, particularly at audio shows, that I no longer enjoy it. Too much of a good thing is a bad thing. Instead, I listened to Life in the Fast Lane. It starts out with an odd mix with the opening guitar lead in the left and right channels but no center image. This happens at several places in the song. The initial center image is the kick drum and snare. The kick drum was impactful and the skin of the snare was crisp. Cymbals were panned to the right and appropriately clangy. Vocals were centered and recessed. It is clear that this cut is all about the instruments, particularly guitar solos and juxtapositions. The term rhythm and pace doesn’t capture the feeling – it boogied. Unfortunately, as I noted in the link, the remaster is highly compressed and hard limited, hence lacks dynamic range. It is relentless. I shifted to the Redbook version to finish the album. Of course I had to turn it up to achieve the same volume level. No fault of the Benchmark HDR though. Often times, we become so fixated on the equipment, we fail to focus on the source.

I needed a break, so I went to my turntable and put on something completely different – Edward Elgar’s Enigma Variations. The Enigma Variations consist of a theme and 14 variations, each bearing a persons initials, and the enigma (long since solved) is to discern from the music whom, from among Elgar intimate acquaintances, the music portrays. It is, perhaps, Elgar’s best known composition. In this 1983 Angel pressing, Vernon Handley leads the London Philharmonic Orchestra in a lush and lyrical rendering. Being a theme and variations, it serves as a terrific pedagogical tool for learning to differentiate similar passages, while at the same time being drawn along a path with a familiar sonic landscape. I was particularly taken with the recurring use of the clarinet which emerges delightfully here and there, usually from a background of second violins. The recording captures its reedy and resonant sound. The tympani are also well portrayed, supplying both an underlying foundation and accent points among the different movements. Drum roll, please.

By way of comparison, I had on hand the Furutech ADL GT40, whose analog input can be switched between MC, MM and line. Running my VPI Scout with Dynavector 20X2 cartridge and Musical Surrounding Phonomena phono stage through the analog inputs of both units revealed the ADL GT40 as lighter in weight, while the Benchmark HDR had a more substantial bottom end and a more fully fleshed out midrange. I found the same to be true using the USB inputs. I attribute these findings to simply a better analog stage in the Benchmark HDR, something you would expect at nearly four times the cost. I also compared the coaxial digital input of the Benchmark HDR with that of my Meridian G68ADV, which has been updated with Meridian’s latest firmware incorporating the new apodizing (minimum phase) filter, fed in each case by the Halide Design Bridge. The nod has to go to the $12,000 Meridian, though the differences were less pronounced. My preference is just that – a preference; it is hard to fault the performance of either.

Conclusion

The Benchmark DAC1 HDR is a bargain at $1895, combining both a USB DAC and an analog preamplifier. It is unlikely that you are going to need more than one analog input, so the flexibility of a multi-source analog preamplifier would likely be under utilized (if at all) by the vast majority of audiophiles. In addition, the corollary to the Benchmark DAC1 HDR – a traditional analog preamplifier with digital inputs – while becoming more common, begins at a substantially high price point, particularly those with balanced analog outputs. The performance of the Benchmark DAC1 HDR leaves little to be desired. Couple it with a good pair of speakers and a power amplifier of sufficient wattage, and you have a system that should keep you satisfied for a long time.

- Frank Berryman

Contact Information

Benchmark Media Systems, Inc.
203 East Hampton Place, Suite 2
Syracuse, NY 13206
Telephone: (800) 262-4675
www.benchmarkmedia.com
sales@benchmarkmedia.com

Associated Equipment

Analog Source: VPI Scout; Dynavector 20X2; Musical Surroundings Phonomena II
Digital Source: Mac Mini; 16GB RAM; Halide Design Bridge; Amarra and Pure Music
Preamplifier: Meridian G68ADV
Power Amplifier: Meridian 557; Acurus A2002; Belles Soloist I integrated
Loudspeakers: Meridian DSP5500; DALI Ikon 6 MK2; Focal 807W Prestige; B&W 683
Cables: Digital: Meridian; USB: Wireworld Starlight; Analog: Mogami/Amphenol (RCA), Mogami/Neutrik (XLR); Speaker: Mogami/Audioquest (BFA/banana); Power: Volex/Marinco
Headphones: Etymotic ER-4S
Accessories: GIK acoustic treatments; dedicated 20 amp circuit; Audience aR2p power conditioner