Weiss Medus DAC

Digital-to-analog converters
Weiss Engineering Medus
Weiss Medus DAC

Weiss has long been at the forefront of digital audio technology. It was the first company I recall making a DAC equipped with a Firewire input for the Mac computers that were used as a source when the whole digital streaming thing got off the ground. There is a reason for this, which is that Weiss has been in studios for a long time. I went to Air studios recently and visited the vinyl cutting room. There in the console I saw two Weiss units; don’t ask me what they do, but assume they had something to do with digital audio in that situation. Studios were the first places that got to grips with digital, so companies that supplied them had a head start over the rest of the audio universe when it came to file streaming. The Medus is Weiss’ flagship digital to analogue converter and its input array can include a Firewire connection even now, but given that this connection has largely died out in domestic PCs the review sample was supplied with an alternative connection in the form of an RJ45 for Ethernet.

This isn’t the first DAC I’ve encountered with an Ethernet input, but they are few and far between. Sometimes called a network DAC, the idea is that you send data from a server or NAS drive directly to the converter without a streaming bridge in between. Given the increase in popularity of audio servers from Melco, Innuos, and the like that have direct Ethernet outputs, this seems like an eminently sensible idea, yet it is still pretty rare. In this converter, its only limitation is that it can’t cope with anything higher than DSD64 as far as one-bit signals are concerned, though it’s good for full 192kHz PCM.

The remaining inputs on the Medus are similarly unusual. They include double-wire connections on inputs 1 and 2: that is, the capability to receive each channel on a separate coaxial or AES/EBU XLR. This approach originates in the early days of high resolution files when the AES/EBU chips were not able to support higher data rates, and again harks back to studio practice. There are a few audio companies that include this option such as Esoteric and dCS, as well as Weiss itself – the Jason CD transport (great name!) includes double-wire outputs. But Weiss doesn’t claim that double-wire offers any advantages over single-wire connections now that the latter are capable of handling high resolution signals. One such being USB, which this DAC has on the same input (3) as Ethernet. This was a cause of some confusion at first, but then I realised that USB comes through on input 3 but Ethernet is selected when choosing input 4 with the front panel buttons or remote. The latter is a heavyweight example of the breed that adds a few useful functions to those accessible from the Medus’ front panel, these include absolute phase inversion, mute, brightness, filter choice, and volume. The latter can also be used to adjust maximum output. Weiss realises that in many systems a preamplifier will provide volume control and the DAC can be set to 0.0dB or full output for such set ups. Having some adjustment of what full output is means that the preamp can be used either in the same range as other sources or at its best sounding level setting. Weiss suggests going for an output level that corresponds with a preamp’s volume control at its midpoint.

The volume control on Medus is a digital type. These are usually quite distinctly compromised, but Weiss points out that theirs is not the usual bit reduction type but one that handles the requantization of a truncated digital signal with dithering. This adds a very small amount of noise but de-correlates the quantization error from the signal resulting in, “a level control with a 24 bit word-length [that] easily rivals the best analogue level controls”. It even has a white paper with sound files to demonstrate their point.

I have yet to find an on-board level control that clearly betters the Townshend Allegri passive preamp, so I made a point of comparing the Medus with its own volume adjustment versus full output via the Allegri. Playing ‘Hot Lips’ by the Hot Club of San Francisco’s Yerba Buena Bounce [Reference Recordings 24/176.4], an early hi-res recording of Hot Club de Paris style ukuleles, guitars, and violin in a very big room. The Medus doesn’t manage to convey that scale as fully as the Allegri. There is a compression of depth and the sound sticks to the speakers. But the sound is very good indeed and it soon became clear that the Medus is a very fine converter – in fact, one of the best I have had the pleasure of using.

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