Schiit Gungnir Multibit and Mjolnir 2

Hardware Review

Schiit Gungnir Multibit and Mjolnir 2
Monday, December 7, 2015
DAC and headphone amp
Richard Barclay

2014 was a busy year of exciting new product releases and refreshes for Schiit Audio, and 2015 has seen no let up. Following the anticipated unveilings of Yggdrasil and Ragnarok, the company’s long-promised ‘cost no object’ statement DAC and amplifier, Jason Stoddard and Mike Moffat have been swift and sure-footed in bringing their recently dethroned flagship DAC, Gungnir, and solid-state headphone amplifier, Mjolnir, back into focus. This summer saw the release of the Gungnir Multibit DAC and Mjolnir 2 tube-hybrid headphone amp.

Multibit Schiit
Gungnir Multibit makes good on Schiit’s ‘trickle-down promise’ to flow state-of-the-art technology from their statement models downward through the hierarchy without violating their pricing structure of affordability. Nicknamed ‘Yggdrasil Junior’, Gungnir Multibit is the first of Schiit’s existing delta-sigma DACs to be made available with the multibit architecture and uses medical-grade precision R2R D/A converter chips never before used in audio applications, and a unique ‘mega-combo-burrito’ filter that is claimed to optimise both the frequency and time domains (thus preserving critical spatial information).  

The filter in Gungnir Multibit is the same 18,000-tap one used in Yggdrasil, but the four D/A converters are 18-bit Analog Devices AD5781BRUZ instead of the much pricier 20-bit AD5791BRUZ. Other sections have been scaled down too, in order to bring “class-leading Yggdrasil multibit performance to a more affordable price point”. More affordable indeed; Gungnir Multibit can be bought for half the price of Yggdrasil and, in accordance with Schiit’s ‘anti-obsolescence’ pledge, existing Gungnir owners can have their delta-sigma models upgraded to multibit. All other features that are present in the previous version of Gungnir remain, including the balanced and summed single-ended outputs, proprietary Adapticlock VCXO/VCO clock regeneration, and the previously optional USB input now becomes standard.

To allay fears from those who think the 18-bit Gungnir Multibit comes up short of competitors whose D/A converters are specced up to 32 bits, it is worth noting DACs that claim more than 20 bits of resolution cannot actually achieve this in practice due to other bottlenecks in the implementation. The ‘Equivalent Number Of Bits’ measurement takes these bottlenecks into account, and reveals that even the highest specced DACs available to audio consumers have an achievable resolution no greater than 20 bits. On-paper comparisons of course tell us very little about sonic performance, which is not only linked to the technology itself, but is also influenced to far greater extent by the engineer’s implementation of it. Moffat’s design of the Mobile Fidelity Sound Labs A/D GAIN mastering system in the early nineties should instill confidence in the calibre of Gungnir Multibit.

 

 

 

 

Solid-state or tubed Schiit?
Mjolnir 2 crystallises a vision Stoddard had several years ago to create a headphone amp that could be completely solid-state or tube-hybrid. It advances its pioneering predecessor by becoming the first inherently balanced tube-hybrid headphone amplifier that utilises Schiit’s unique balanced, differential circlotron-style topology. Many attributes from the first Mjolnir have been retained, including the capability to drive most of the current- or voltage-hungry headphones in existence. Halving as the load doubles, its 4V balanced output delivers 8W RMS per channel into 32 ohms and 425mW RMS per channel into 600 ohms. Some specs have also been improved, such as the power supply rails which have been uprated from 90V to 200V. More interestingly, several features have been added to Mjolnir 2 to improve its connectivity and versatility.

The first of these is a gain switch that can be toggled between 8 (18dB) and 1 (0dB), allowing users with even the most sensitive of IEMs to enjoy an inaudible noise floor and usable range on the volume pot. Stoddard’s biggest regret about the first Mjolnir has also been adressed, namely single-ended outputs. Mjolnir 2 now adds a summed single-ended headphone output and summed single-ended RCA pre-outs for good measure, bringing connectivity parity to users of both topologies. The power of the 2V single-ended headphone output is one quarter of the balanced (half the voltage swing = quarter the power), but is still more than adequate for most ‘phones.

Mjolnir 2 is available to purchase with either Schiit’s stock 6BZ7 tubes or their all-new LISSTs (Linear Integral Solid-State Tubes), which are straightforwardly described as “a pair of depletion-mode MOSFETs in a tube-sized can”. The LISST is what cleverly turns Mjolnir 2 back into a purely solid-state amp with a sonic profile very similar to, but improved upon, its predecessor, according to its designer at least. The choice between vacuum tubes and LISST ultimately comes down to personal sonic preference. However, if you want to have your Schiit and eat it, you can of course purchase both. This would allow flexibility, for example, to switch things up based on mood, connected ancillaries and source material, or aid in the preservation of some uber expensive NOS tubes for special occasions. To which end the stock 6BZ7 tubes can be swapped out for 6DJ8, 6922, ECC88 or 2492 tubes, so listeners can spend days, weeks, or even months rolling the sound to taste.

 

 

 

 

Although Schiit soak test their products prior to shipping, there is anecdotal consensus that both Gungnir Multibit and Mjolnir 2 benefit significantly from a longer initial burn-in, during which time permanent sonic changes are reported to occur in both models. Roughly 300 hours for Gungnir Multibit and around half this time for Mjolnir 2 is recommended for the sonic signature of each unit to plateau. A particular caveat of Gungnir Multibit - and Schiit’s other multibit DACs - is the recommendation to leave it powered on continually for optimum performance. The multibit D/A converter chips become more accurate as they reach thermal equilibrium - resulting in increased dynamic range and decreased jitter - and this equilibrium apparently takes considerable time to achieve. Those unable or unwilling to leave audio equipment powered up 24/7 should note that while I did find that the sound improved the longer it was on, I certainly wasn’t underwhelmed by the performance of Gungnir Multibit during its first few hours from cold. To learn what each model brings to the party, Gungnir Multibit and Mjolnir 2 were first evaluated individually within the context of my existing system (listed at the end of this review), before being paired together to discover how well they stack up as a complete solution.

Deep Schiit
Gungnir Multibit’s sonic signature is intriguingly different to any other DAC I have listened to, and it was initially quite a challenge to hear recordings, with which I thought I had intimate familiarity, presented in this way. Music emanates from a distant, inky black expanse, ebbs and flows with natural fluidity, and possesses an incredible smoothness and depth that is reminiscent of a high-end analogue system. There is a distinct absence of digital glare and transients are reproduced cleanly with grainless decay, contributing to a more solid and focused sound with longer and quieter pauses between notes. It has been suggested that this may be the result of more accurate rendering of transients, that are no longer unfaithfully lengthened by the pre- and post-ringing inherent in delta-sigma converters. Many DACs often struggle to do smoothness and detail and end up prioritising one at the expense of the other, but Gungnir Multibit achieves an excellent balance of both. It is not a forensic analyser, but its proficiency in reconstructing spatial cues grants listeners a level of access to the recording space that few other DACs do at this price. Gungnir Multibit provides more room around individual instruments, expands the boundaries of the performance venue, and most interestingly of all increases the distance between the musicians and the listener. The latter is not what I would normally consider to be a desirable quality as it implies a loss of intimacy and connection, but here the increase in distance has the opposite effect. By presenting to the foreground, delta-sigma converters tend to produce a perceivably vibrant and frenetic sound at the expense of micro-dynamics and depth. It is like being in the front row at a packed concert; the immediacy of the visual spectacle and ‘wall of sound’ are thrilling, but you are too close to appreciate all of the individual elements at their intended distances, intensities and timings, and many subtleties are obscured as a result. Listening to Gungnir Multibit it is like being alone in the auditorium; there is nothing to distract your attention from the musical mastery unfolding before you, and you can sit a few rows back, relax and fully appreciate the intended scale, dimensionality and dynamism whilst still being completely immersed in the experience.

 

 

 

 

Mjolnir 2 immediately impresses with its exceptionally low noise floor. This amp is super quiet and provides a spookily muted backdrop for low-level detail to emerge from, especially on the low gain setting which is so silent through over-the-ear headphones you would think you were in an anechoic chamber!  The Alps volume pot tracks with very high accuracy and remains transparent and channel-balanced on both gain settings all the way down to whisper-quiet levels. The low gain setting is very useful in practice, not only for IEM users but also for those with less sensitive ‘phones, as it allows you to dial in your desired listening level with near infinitesimal accuracy. With an abundance of power on tap, the amp drives MrSpeakers Ether (22 Ohm) and Sennheiser HD600 (300 Ohm) headphones effortlessly. That said, in solid-state mode (i.e. LISSTs installed) I was a little underwhelmed with Mjolnir 2’s sonic presentation. It is remarkably neutral, linear, clean and fast, however it is also quite tonally bland and spatially unidimensional. Instrument timbres are somewhat homogenised and lack texture, and the overall presentation is a bit uninspiring and difficult to engage with. Swapping out the LISSTs for the stock 6BZ7 vacuum tubes brings Mjolnir 2 to life. Personality and musicality is injected without sacrificing the commendably impartial tonal balance, and the soundscape becomes rich, variegated and palpable. The previous overly lean and grippy bass is allowed to bloom and have its tuneful impact felt without being undesirably sluggish. Mids are majestically mellifluous in tone yet remain very open, detailed and transparent. Highs are impressively extended, invigoratingly crisp and articulated with improved micro-detail distinction. The soundstage grows in all dimensions with instruments more clearly layered and spaced around the listener in an enveloping sphere of sound, giving a heightened sense of being at the epicentre of the performance. The stock tubes are not too ‘tubey’ sounding and retain an excellent level of transparency, neutrality and speed. They are in fact a very good bridge between dry solid-state sound and the more euphonic sound that vintage NOS tubes typically produce, and are an excellent starting point for those wishing to enjoy the best of both worlds.

 

 

 

 

Together, Gungnir Multibit and Mjolnir 2 deliver an intoxicating listening experience and would constitute an ‘end-game system’ at this level for many audio enthusiasts, especially if the balanced topologies in both are exploited. While the single-ended circuits are excellent, trading up to balanced elevates the performance to exceptional - and I dare say peerless - in this price range. This should not surprise, since both models were designed from inception to run balanced. Schiit are resolute about the superiority of balanced over single-ended when properly implemented and in the context of these components at least I am compelled to concur. I detected improvements in clarity, presence, separation, spaciousness and dynamics each time I replaced a single-ended connection with a balanced one, first between the DAC and amp and then between the amp and headphones. The difference between all single-ended and all balanced was not a trivial one and, in my experience, only the latter allows Gungnir Multibit’s resolution and musical fluidity and Mjolnir 2‘s rich palette of textures and vivid holographics to be fully appreciated.

Verdict
Schiit Audio has taken many by surprise with the speedy inclusion of its flagship multibit technology into the Gungnir DAC, and transformation of the Mjolnir headphone amp from its  debut solid-state incarnation into a tube-hybrid design that can neatly revert to the former. Individually, these are laudable products with interesting USPs that set them apart from pricier peers. Together, the two units complement each other exceptionally well and offer a seductively revealing, immersive and textured listening experience in which music is allowed to breathe freely. Their combined price-to-performance ratio verges on the ridiculous. For well under £2k you can invest in a highly resolving, emotionally engaging system that is both multifunctional and customisable, and has provision for future upgrade when further advances are made. Jason Stoddard and Mike Moffat may be long-toothed stalwarts, but Gungnir Multibit and Mjolnir 2 demonstrate that they are not merely going through the motions with trivial tweaks or pandering to short-lived fashions. In fact if Stoddard’s recent comments are anything to go by, there is even more in the Schiit pipeline for 2016 to really stir up the consumer audio industry.

Ancillaries used during testing:
Computer hardware & software: Mac Mini 2010, Mac OS 10.6.8, Audirvana Plus 1.5.12, iTunes 11.4.
Headphone reference system: Schiit Bifrost Uber DAC, Schiit Valhalla OTL tube headphone amp, MrSpeakers Ether and Sennheiser HD600 headphones.
Main reference system: Schiit Bifrost Uber DAC, Yamaha A-S2000 integrated amp, Tannoy Monitor Gold 15 and Tannoy Autograph Mini loudspeakers.

Specifications: 

Gungnir Multibit
D/A Conversion IC: Analog Devices AD5781BRUZ x 4 (2 per channel, hardware balanced configuration)
Digital Filter: proprietary Schiit bitperfect closed-form digital filter on Analog Devices SHARC DSP processorAnalogue stages: Fully discrete JFET buffers for balanced output and discrete JFET summing stages for single-ended output, direct coupled throughout
Frequency Response, analogue stage: 20Hz-20Khz, +/-0.1dB, 1Hz-200KHz, -1dBMaximum Output: 4.0V RMS (balanced), 2.0V RMS (single-ended)
THD: Less than 0.005%, 20Hz-20KHz, at full outputIMD: <0.004%, CCIRSNR: > 115dB, referenced to 2V RMS
Inputs: Coaxial RCA SPDIF, BNC SPDIF, Optical SPDIF, USB Input
Capability: up to 24/192 for all inputs
Input Receiver, SPDIF: AKM 4113
Input Receiver, USB: C-Media CM6631A
Output: One pair XLR balanced and two pairs RCA single-ended
Output Impedance: 75 ohms
Clock Management: Bitperfect clock management at all native sample rates via Adapticlock analysis and VCXO/VCO regeneration, plus asynchronous USB Gen 2 module
Power supply: two transformers, 8 stages of regulation, separate local supplies for critical sections
Upgradability: Modular USB Input Card and DAC/Analog Cards
Power Consumption: 20W
Size WxDxH: 406 x 222 x 57mm (16 x 8.75” x 2.25”)
Weight: 5kg (11 lbs)

Mjolnir 2
Frequency Response: 20Hz-20Khz, -0.1db, 2Hz-400KHz, -3dB
Maximum Power RMS per channel: 32 ohms: 8W, 50 ohms: 5W, 300 ohms: 850mW, 600 ohms: 425mW
THD: <0.005%, 20Hz-20KHz, at 1V RMS
IMD: <0.006%, CCIF, at 1V RMS
SNR: >104db, unweighted, referenced to 1V RMS, in low gain mode
Crosstalk: >-75dB, 20 Hz-20KHz
Output Impedance: 1 ohm (high gain), 0.3 ohms (low gain)
Gain: 8 (18dB) or 1(0db), via front-panel switch
Topology: Tube voltage gain or solid-state tube voltage gain, cross-shunt push-pull Crossfet output stage, noninverting, single voltage gain stage
Power Supply: specific Circlotron 4-secondary output stage transformer with over 65,000uF filter capacitance, plus dedicated transformer for high-voltage discrete-regulated front end stage with 200V rails and over 4,000uf of filter capacitance
Inputs: one pair balanced XLR, one pair single-ended RCAs, switchable via front panel switch
Outputs: one 4-pin balanced female XLR, one ¼” TRS phono, one pair 3-pin male XLR preamp, one pair single-ended RCA
Power Consumption: 45W
Size WxDxH: 406 x 222 x 57mm (16 x 8.75” x 2.25”)
Weight: 5.9kg (13 lbs)

Price: 
Gungnir Multibit £1,000 (upgrade from £465)
Mjolnir 2 £720
Manufacturer Details: 

Schiit Audio
www.schiit.com

Distributor Details: 

Electromod
T +44 (0)1494 956558
www.electromod.co.uk