Bolting on an external digital-to-analogue converter (DAC) can be a one-step process to improve the sound quality of your laptop or PC. And there’s been a definite upsurge in USB-audio DAC popularity recently, in part inspired by the work of audio electronics engineers who’ve realised how good this technique’s results can be when applied properly.
One breakthrough was in the discovery of the so-called asynchronous-mode USB audio, whereby the outboard convertor takes control of the flow of data from PC.
Done right, this can rid the final sound of the hard, unrelenting and glassy sound of ‘digital’, often caused by timing distortions (jitter) – small clock errors from the PC that skew precision of the decoding process.
It’s to these kind of digital artefacts that analogue die-hards will point, when trumpeting the warmer, better-integrated and more natural sound of music before digital audio in general, and of computer audio in particular.
While decent-sounding USB audio DACs can be found for a few hundred pounds or less, such as the HRT Music Streamer II, these won’t satisfy the music lover who’s used to the sublime sound of a high-end convertor.
Remember, the finest D-A convertors can cost upwards of £2000, sometimes beyond £10,000. And yes, anyone can hear the improvements such upmarket kit makes, not just chin-stroking audio engineers and hi-fi buffs.
But such classic DACs are typically locked out of the world of computer audio, as their input array extends only to legacy audio connectors such as RCA phono and BNC sockets for an S/PDIF (Sony/Philips digital interconnect format) connection. That exclusion need no longer apply.
Enter Musical Fidelity V-Link
The Musical Fidelity V-Link is a simple device that does one thing, but does it unerringly well. It connects to your PC or Mac by USB 2.0 on one end, and offers up two digital audio interfaces on the other: RCA coaxial and Toslink optical. To overcome PC jitter issues, it uses asynchronous-mode USB transfer.
In short, it’s the missing link between any computer that can host and play digital music files; and any hi-fi system with a digital audio input.
The Musical Fidelity V-Link is a simple black-painted aluminium box, with no on/off switch nor other buttonry. Its energy draw for the few chips inside is minimal, and so takes its power from the 5V USB bus.
Once connected to a PC, it automatically appears as a sound device, requiring no proprietary drivers that can potentially destabilise your system. And in another blow to the similarly specified and priced M2Tech HiFace, it introduces no latency in its decode chain, so is happy to work in perfect synchronisation with film and video material too.
Musical Fidelity cites lab measurements that suggest the unit introduces no jitter of its own whatsoever, the only new traces on the graph plots being those inherent to the measurement equipment itself. And listening to music through the V-Link, we heard what may be the closest approach to the original (PC) sound.
In a reference system comprising Apple Mac mini (Early 2009) one side, and dCS Purcell and Delius convertors the other, feeding Leema Acoustics Tucana II amplifier and B&W 802D loudspeakers, we were able to compare the sound of digits from the PC, to those served up by a CD disc transport, the system’s dCS Verdi.
Once we’d re-established that iTunes is a far from transparent music player, and switched to VLC to play uncompressed or lossless audio files, we found a sound that was close to the reference CD transport.
Music kept its pace and slam, although some of the easy fluidity of our upsampled CD sound was lost on the way. Like run-of-the-mill CD sound, a hint of chrome-edged sheen crept in over the sound that never let us forget this was a CD playing. Importantly though, the pace and meter of the music was essentially preserved.
The Musical Fidelity V-Link’s very simplicity extends to its grounding arrangements; there is no galvanic isolation between input and output stages. The influence of ground planes can take on the mystical in high-end audio circles.
And when delicate audio extends into the PC domain, there’s enough high-frequency noise circulating to bleed into the system and unsettle the sound. That’s one reason why outboard audio conversion can trump that from inside a PC; the proximity of RF noise from processors, clocks, graphics cards and high-frequency switching power supplies makes for an environment quite hostile to low-level analogue music signals.
So there’s every chance that the electrical bridge from PC to hi-fi through the USB cable acts as a conduit for some of PC’s radio-frequency chaff, and which good audio kit works so hard to keep out.
Breaking the chain
It’s fortunate, then, that the Musical Fidelity V-Link offers an alternative output that may suit some tastes or setups better, in the old optical standby: the Toslink S/PDIF connection. The standard is not universally admired by music lovers, as the format can introduce its own form of timing errors. But boy, did it transform the sound we heard through the Musical Fidelity V-Link.
Used with its Toslink output, the Musical Fidelity V-Link turned around the sound into one of squeaky clean purity, deathly black silences opening out in spaces in the music. The shimmer of cymbals and zing of strummed guitars rang out and upwards into natural, stratospheric extension.
Pinpoint stereo imaging was one casulty, as individual voices seemed to occupy a larger diffuse area, while we could never be quite so certain of the seating arrangements of the orchestra. But the pace of the music didn’t suffer, the foot remaining as captivated as the ear.
While rock bass guitar sounded fractionally less forthright and, well, rock-y, the expression and timbre of low-frequency basslines was upgraded to ‘studio edition’ standard. The trade was worthwhile.
So going the optical route provides complete electrical separation between noisy PC electronics and sensitive audio electronics. The collateral damage can be in the perceived ‘drive’ to some music, and some clouding of stereo precision.
Personal preferences can drift, but right now we find the optical version allows the best expression of musical intent in recordings, and the wealth of detail in instruments’ sound textures is utterly compelling.