The D/A converter stage features the new AK4490, a 32-bit stereo DAC which as the flagship of AKM's Verita range claims a THD+N of -112dB for a voltage output of 120dB dynamic range. It integrates a newly developed switched capacitor filter called OSR doubler which reduces sound degradation from noise shaping for a flat noise floor up to 200kHz. A symmetrical layout for right and left channels prevents signal quality deterioration. The AK4490 integrates five digital filters for complete adaptation to each file format. It supports DSD64, 128 and 256 as well as PCM up to 384kHz but excludes 176.4kHz or perhaps considers all 176.4kHz PCM files as DoP. It's still possible to read this format with the C8+ but it will be terribly noisy. For Direct Stream inputs, the AK4490 of course contains an integrated low-pass filter.

Each stage is deeply regulated by quality capacitors like Kernel and SCR parts. The white SCR 25µF filter modules in fact were specially designed for Metronome Technology. The NOS JAN 6922 output stage employs two Lundahl LL1545A transformers on its outputs whilst the high-speed operational amps used on the transistor outputs hide inside four small metal boxes. All digital inputs have the same independent decoding circuit without TTL interface. All inputs except USB work from 44.1-192kHz. USB limits at 384kHz/DSD512. In terms of final performance, Metronome Technology claim dynamic range of 145dB and a noise floor of -140dB.

Sound.  The Metronome Technologie C8+ had amazing transparency on its S/PDIF and AES/EBU sockets but was compromised on USB. As such, I thought it the overall most transparent D/A converter I had opportunity to host.  The C8+ delivered plenty of detail and superb clarity. The most transparent output seemed to be the transistorized one, with the tube output being a bit more euphonic and pleasant on certain recordings but not as precise as the one called AOP. With the balanced output's high 5V out (3V on RCA) driving my Grimm Audio TPM cables, the transistor stage became rather unforgiving of bad recordings. Here the tube output was less critical. Using the unbalanced output, I preferred solid state with most recordings but not exclusively so. That option to choose is both benefit and liability since it might have you worry and switch back and forth unnecessarily to check that you made the best choice. Whilst far easier to use than the Trinnov Amethyst, this duality remained fixed in my head for a good part of my time spent with the C8+ until I finally decided that my preference was the solid-state output. Coming back to the sonic fingerprint of the big Metronome DAC, the main features were uncommon transparency and impressive dynamics. In my opinion, it more or less shared the same transparency with the best ladder converters from MSB, Totaldac and Aries Cerat, then added dynamics. In terms of tone, the choice of AKM chip tended to emphasize clarity and precision. As an Esoteric SACD player owner, this was not strange. Compared to my ESS network player, I noticed a different fingerprint. The Lumin S1 had warmer and somewhat more diversified timbres especially on strings whilst the Metronome C8+ provided more detail and a higher degree of transparency and dynamics. The choice between solid state and tube output stages was more a question of overall presentation. The solid state output stage was a bit more forward and dense, the tube output more laid-back, airy and deep. These were not huge differences but sufficiently distinct to switch from one to another depending on recording.

I had six different transports during my test: my Macbook on its USB output with JRiver Media Center 21, a Windows XP machine with Foobar 2000, my Lumin S1 network player via BNC and several coax cables through a BNC/coax adapter, my Esoteric K-03 via S/PDIF, the Etalon Streamer via USB boosted by a Regen repeater and the Auralic Aries Femto network player through its entire range of digital outputs. I don't remember ever having used such diversity of digital transports before. Because I had sound quality issues with USB, I felt it important to try a whole range of digital transports. Starting with coax, I had very good results with the Lumin S1, Esoteric K-03 and Auralic Aries with Femto clock and linear PSU. I did not notice significant differences between these network players, with the Lumin having perhaps a bit more dynamics, the Auralic being more laid back. The C8+ provided a more life-like sound that made the music more involving. That was a true achievement as I believe most Lumin S1 owners would hardly complain about the involving nature of their network player. Yet the Metronome went significantly further, adding transparency and PRaT. Nevertheless, any C8+ assessment will depend on selected recordings. It was especially impressive on voices and live recordings. When I switched to big symphonic pieces, I sometimes found my ESS Sabre DAC more accurate or able to better highlight subtle tonal variations where the AKM-based Metronome was more about transparency and resolution that let me here some very small details I hadn't noticed before. In that sense, the Metronome had tremendous resolution.

My Esoteric SACD player meanwhile delivered no significant improvement through its digital output. Perhaps the same Asahi Kasei DNA made the sound of the K-03 as transport a bit more liquid and holographic but not significantly so. I did notice better bottom-end extension however when used as an integrated player instead of being run through the Metronome C8+. This was only a small surprise as my Esoteric had in the past nearly always shown better results when I used it as an integrated source and not simple transport. Setting the balanced analogue outputs on it at +6dB, I had sound levels quite comparable between the analog output stage of the K-03 and the Metronome. Thanks to its various digital outputs, the versatile Auralic Aries was useful to compare the Metronome D/A converter to other contenders. Via AES/EBU, the C8+ delivered more convincing performance than the TotalDac Dual, which admittedly is Vincent Brien's entry-level model sold manufacturer direct to French clients for big savings - not the case for Metronome. Beyond pricing and distribution strategies, I still found it useful to contrast the C8+ with a well-reviewed contender. Returning to sole consideration of sonics, the C8+ provided significantly higher transparency, detail, resolution and dynamics.  Both machines have higher output voltages, about 3/6V on RCA/XLR respectively which posed no issues for my reference preamp but did diverge from the industry standard.  RCA and XLR performed identical with my Coincident Technology Statement linestage. The TotalDac was slightly earthier and warmer, in other words a bit recessed in the treble, the Metronome C8+ more neutral, linear and far more transparent.

The Metronome C8+ in fact played in a different league than TotalDac's entry model. That meant elevated performance since in my book the TotalDac Dual remains a very prestigious DAC realization. Compared to far more affordable units like the Metrum Acoustics Pavane or Comet Exogal, the Metronome was definitely a more open door to higher resolution and transparency. In the field of tonal accuracy, it was difficult for either to really compete even if the C8+ could be considered on the cold side of neutrality whereas the Pavane and Dual had a warmer tonal balance. Still, I thought the Metronome the more accurate and realistic from that particular perspective. In terms of vividness, the small American Comet delivered very enjoyable results but didn't go as far as the French.