Metrum has always done things a bit differently. For a start, all its products are NOS (non oversampling) types, which removes a stage of filtering, and they all have ladder DACs built with discrete components designed rather than an off-the-shelf chip. From these facts alone, you know that Metrum’s founder and designer Cees Ruijtenberg is not the type to follow the crowd: his is a path rather less well trodden, and with the Pavane he has gone further.
The Pavane uses an FPGA-based forward-correction module to overcome the switching noise that undermines the linearity of ladder DACs at low levels. Essentially, it processes both MSB (Most Significant Bits) and the LSB (Least Significant Bits) in the same top half of the converter. This means the Pavane increases the level of the LSBs prior to conversion and sends 12-bits to each DAC module, which means that the lower level or Least Significant Bits have the same signal-to-noise profile as the MSBs. Levels are then corrected in the analogue stage so that you get the full 24-bit depth with maximum linearity. It’s not simple, but it seems to work – and rather well at that.
The Pavane, which incidentally is Metrum’s top model, is a very nicely built piece of audio engineering, and has a machined aluminium front and sides, topped by black glass. I don’t recommend using it to keep your coffee warm, but it has a distinct coffee-table look. Input buttons are arrayed on the front next to an orange light that comes on if no signal is present on a given input. The sockets on the back consist of AES/EBU, USB, optical Toslink, and coaxial on both RCA and BNC connections. I was surprised to find a rather nice but small remote control featuring just the one button in the box that changes the input. The DAC’s analogue outputs are on RCA phono and balanced XLR, the Pavane being a true balanced converter.
Inside the box there are a lot more parts than usually encountered in a DAC, most obviously you have two ladder DAC boards each supplied by its own dedicated mains transformer and power supply. Elsewhere there is a USB receiver, the FPGA chip where the mathematical magic goes on, and a Lundahl transformer for summing the differential output of the DACs prior to the single ended output stage. There is also a third transformer for these elements. All in all it’s a comprehensively engineered piece of kit that eschews the bells and whistles of Bluetooth, network streaming, and volume controls in an attempt to be the best digital to analogue converter that Cees could produce. And given that his more affordable DACs such as the Octave and Hex are pretty stunning, this is a promising start.