As is often the case, I came across the product which fulfilled my desires while actually searching for something else. I was originally looking for a quality headphone amplifier to power a pair of Sennheiser HD 650 headphones (pictured below) and found many recommending products from pro-audio company Benchmark Media.

While browsing their products, I discovered the DAC1 PRE which packs a 24-bit / 192KHz digital analogue converter (DAC), pre-amplifier and one of the company’s reference HPA2 headphone amplifiers (with twin outputs) into a remarkably compact unit measuring just 249x45x246mm and costing $1595 USD.

The unit features one analogue, one optical digital and three coaxial digital inputs, along with a USB port and the choice of balanced or unbalanced outputs. The USB port is what makes it really special for me, allowing the DAC1 PRE to act as an external USB ‘sound card’ for PCs or Macs, but with capabilities and quality way beyond the norm.

In the past, most USB audio devices have fallen into two camps: native devices which may not require drivers, but which can’t handle audio beyond 16-bit / 48KHz, and higher-end devices which achieve high resolution output with custom drivers, but sometimes at the cost of broad compatibility and stability. Benchmark’s Advanced USB Technology claims to deliver the first native USB solution which supports bit-transparent streams at up to 24-bit / 96KHz, without the need for any special drivers.

24-bit capability is important even when playing 16-bit sources because digital volume controls and mixers increase their word-length, which become subsequently compromised when delivered with 16-bit resolution. 24-bits provides headroom for these changes. USB sources also benefit from the DAC1 PRE’s Ultralock Clock system which claims to eliminate jitter on any digital input.

To put the theory to the test, I connected the DAC1 PRE’s balanced outputs to a Meridian 557 amplifier, which in turn powered a pair of B&W Nautilus 802 loudspeakers. A Meridian CD500 and my trusty XP MCE PC were used as sources, the former connected using a pricey Nordost Silver Shadow coaxial digital cable, and the latter with a bog-standard USB cable supplied with the DAC1 PRE. In this configuration the DAC1 PRE was being used both as a DAC and pre-amp.

Starting with the CD transport, the DAC1 PRE sounded very neutral with a wide soundstage and precise imaging; in Hifi terms it was very transparent, and to my ears, sounded great. I then switched over to my media PC, which as Benchmark promised, required no drivers or configuration – although to ensure bit-transparency, you’ll need to set the application volume control to maximum and switch off any filter effects.

After listening to many products which disappointed in some regard the result was quite a shock: audio files encoded using FLAC and played using Winamp or Windows Media Player sounded essentially the same as the original CDs played from the high-end transport. Starting both the CD and media file simultaneously allowed me to switch between sources for a direct A-B comparison and it was extremely close. There was arguably a little colouration from the CD transport, which became more noticeable with cheaper cables, but the amazing thing was how good the PC sounded: it was the best I’ve ever heard from a computer.

It’s also fun to connect the DAC1 PRE to a laptop or any other computer and achieve exactly the same result – the native USB aspect of the unit essentially makes it device independent, and you should achieve great quality sound regardless of your computer hardware and USB cable. This is very liberating in Hifi terms where the source hardware and interconnect make a massive difference. So long as the source file on your PC is lossless or uncompressed, and the application volume control is set to maximum, you should be in for a treat. Benchmark offers further application notes.

I can also highly recommend the Sennheiser HD 650 headphones, which are proving to be a perfect match for the DAC1 PRE. They take a little running-in, but after a few days open-up to reveal a wonderfully wide and transparent soundstage. Considering how much you’d need to spend on power amplification and speakers to achieve a similar standard in sound quality, they represent a bargain. Indeed Benchmark itself recommends these models for use with the DAC1 PRE.

Please note the HD 650’s require decent headphone amplification to drive them though, so they’re not suitable for use with most portables, or indeed lesser separates; sadly despite including a quarter inch to 3.5mm jack adapter in the box, you won’t be using them very successfully with an iPod.

The Benchmark DAC1 PRE finally fulfils my long-term desire to match the quality of a high-end CD transport from a digital collection stored on a standard PC. It comes highly recommended for anyone who wants top-notch stereo performance from their PC, but beyond the USB capability, you’re also getting a high quality DAC, pre-amp and headphone amplifier.

In high-end Hifi terms, it simply represents great value for money and comes Highly Recommended. Note: since evaluating the DAC1 PRE, Benchmark has released the DAC1 HDR version which includes a remote control with motorised volume adjustment for $1895 USD. See Benchmark Audio.

If you’ve struggled or succeeded in achieving Hifi quality sound with your own PC, or simply want to discuss the solutions described here, we’d love to hear from you in the forum!


Gordon's other hardware configurations for great sound quality!

The sound card: an M-Audio AP 2496 running the right software.

The streaming appliance: a Logitech Squeezebox with some neat modifications.