December
2018

Country of Origin

Poland

Cube

Reviewer: Srajan Ebaen
Financial interests: click here
Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 14.4), PureMusic 3.02, Audirvana 3, Qobuz Hifi, Tidal Hifi, Fore Audio DAISy1, COS Engineering D1, Denafrips Terminator, Soundaware D300Ref,  AURALiC Vega 
Preamplifier: Nagra Classic, Wyred4Sound STP-SE Stage II, Vinnie Rossi LIO (AVT module)
Power & integrated amplifiers: Pass Labs XA30.8; FirstWatt SIT1 monos, F5, F6, F7; Goldmund/Job 225; Aura Note Premier; Wyred4Sound mINT; Nord Acoustics NC500 monos; LinnenberG Audio Liszt monos
Loudspeakers: Audio Physic Codex; Cube Audio Nenuphar; Albedo Audio Aptica; EnigmAcoustics Mythology 1; Boenicke Audio W5se; Zu Audio Druid V & VI & Submission; German Physiks HRS-120; Eversound Essence
Cables: Complete loom of Allnic Audio ZL3000 and Zu Event; KingRex uArt, Zu and LightHarmonic LightSpeed double-header USB cables; Tombo Trøn S/PDIF; van den Hul AES/EBU; AudioQuest Diamond glass-fibre Toslink; Black Cat Cable redlevel Lupo; Ocellia OCC Silver
Power delivery: Vibex Granada/Alhambra on all source components, Vibex One 11R on amps/sub
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands 
Sundry accessories: Acoustic System resonators
Room: 4 x 6m with high gabled beam ceiling opening into 4 x 8m kitchen and 5 x 8m living room, hence no wall behind the listening chairs
Review component retail: starting at €7'490/pr [€8'990/pr with amorphous transformers]

Common ground or higher ground? Typical tubes with which to electrify guitars are the EL34/84, 6L6, 6V6, 6550 and 5881, pentodes all. In today's push/pull hifi amps, the kinkless tetrodes KT88 to KT150 are more popular but the EL34 pentode remains included. Boutique single-ended valve amplifiers focus on direct-heated triodes like the 10Y, 101D, 45, 50, PX4/25, 2A3, 300B and 845/211. Rare makers like Audiopax of Brazil repurpose KT88 strapped to triode.

Yet the small EL84/6BQ5 is less common.

After all, triode-strapped tetrodes or pure pentodes are picked to increase not diminish the single-ended power over pure triodes. Likewise, it's the more powerful tetrodes and pentodes which get championed for push/pull circuits to compete against transistors. They minimize just how many bottles must be paralleled to hit a certain power target. It's always easier to sell a buyer on more power than less; and less complexity to make it so. How many 80-watt 300B monos like Canary Audio's do you know? Those must run eight costly 300B per channel when two KT120 by Audio Research do the same job.

With  91dB Diapason Adamante during an Art Gallery showing.

At 6 watts, a single-ended EL84 amp makes less than one equivalent 300B which can be sold for a lot more. In push/pull, 50 watts would take an octet of 6BQ5. As a lowly-powered pentode, our EL84 is an outlier choice in home hifi even though it remains one of very few tubes which specifically were designed for audio use, not re-purposed from other applications. That less-popularized fact is why even amongst direct-heated triode cognoscenti, the EL84 can be an acceptable commoner's choice. It's why years ago, I commissioned Trafomatic's Sasa Cokic for the 25wpc Kaivalya monos which remain in their portfolio.

Today's MySound Cube monos from Poland wring a logical 12 watts from a single pair of EL84. In certain corners, creative marketeers refer to such circuits as single-ended push/pull even though the term is an oxymoron. But it does properly highlight a single output device per half wave or phase as being the absolute minimum hence 'purist option' for push/pull architectures. The 10kg pure class A Cubes drive their EL84 pairs with single 12AX7 for a published 16Hz – 65kHz response. They are available as pure power amplifiers; or fitted with 48-step Khozmo passive attenuators to morph into single-input twin-chassis 'integrateds'.

At the 2018 Warsaw show with Blumenhofer speakers, Métronome disc player and SOtM digital.

Once we shift eyes from specifications to appearance, we take in stained Bubinga wood cheeks which offset the fascia in matching red, black, white or gold. We admire stylish glass covers which echo Engstrøm's and can be had in smoked glass to complement a black chassis.

Such stylish extravagances suggest more than functional squareness. The amorphous-core transformer option confirms it. So do show sightings with high-efficiency horns to speak to very low noise.

Once we learn that their genesis was predicated upon wanting perfect amps for Sonus Faber Extrema speakers; that to this day MySound make no other amplifier; then contemplate the brand name's implications… we might suspect glacially-moving spirits more obsessed with perfection and pleasing themselves than playing marketing games.

UK distributor G Point Audio discovered and promoted them since 2012 when they debuted in Munich. At the end of 2018 thus six moons later, they still had booked only two reviews in English. A cubist revival seemed in order. Our resident Cube Audio Nenuphar widebanders also from Poland would be ideal partners to kick into Cube Squared mode. The company's Artur Biniak proved willing and these dice were cast. For the reasons given, the market place for EL84 amps is quite narrow, even more so for those priced as statements. For example, the Still Audio EL84 integrated reviewed by prior contributor Jeff Day for Positive Feedback gets $2'895. The Canadian Triode Lab which Frederic reviewed in this pages nets from €3'500 – €7'000 depending on performance package. A pair of Mahi monos from the pro/home experts at Manley Labs set you back $4'900. A pair of Trafomatic Kaivalya was €5'500 factory direct when I bought then reviewed mine.

With 100dB hORNS Universum 3-ways and matching MySound passive preamp at Munich.

Today's Cube starts at €7'490/pr. If it ran 300B to make just half the power, nobody would bat an eye lash. With EL84, perceptions react differently. My review will ask whether that's just a knee-jerk reaction which ought to be tamed although my Kaivalya adventure already previewed that territory. To recube the tube with new output glass from Watford Valves could be done for as little as £9.25/ea. with JJ or £55/per with NOS General Electric glass when I wrote this. A rare EL84/CV2975 Mullard from Langrex fetched £75 just then. That's a very different proposition to exotic NOS even current direct-heated power triodes.

Because the EL84 aka 6BQ5 aka N709 aka 6P15 remains beloved by guitar wranglers, reliable current supply from names like ElectroHarmonix, Genalex Gold Lion, Psvane, Shuguang, Sovtek and Tungsol is guaranteed. Equivalents are the 7189/A and so-called extended-ratings versions like the E84L/7320 Siemens shown above and the Russian 6P14P-EV. Both are rated for more than 10'000 hours. With plenty of NOS stock including the famed Yugoslavian EI, tube rollers have serious options. And unlike the classic Leak Stereo 20 which launched in 1958, today's 21st-century Cube prefers solid-state rectification to GZ34 and also eliminates the EF86 for even less glass, hence lowered maintenance. The only rare routine will be to check on bias via the rear-panel controls since this isn't an auto-bias design to make more power.

The natural Cube companion would be this fully optioned-out 3-chassis PreCube. That combines an 384kHz PCM R2R DAC with relay-switched resistor ladder attenuator over a -64 to 0dB range with an Amanero DAC for DSD128. There's an organic light-emitting diode display, Mundorf Superior caps, Vishay/Dale resistors, two analog inputs, S/PDIF coax and USB digital, remote control and for the obligatory vacuum bottles in the output stage, twin ECC82/12AU7 and twin E88CC/6922. Plus there's a third box, the external low-voltage power supply.

The two MySound owners were clearly intent to control the entire electrical signal path. Marek Dyba's prior Cube review even intimated that another amplifier based on his favourite direct-heated triode was in the works but its launch data anyone's guess since these perfectionists were in no rush.

As they say on their website, "why tube technology when progress has given us transistors, integrated circuits and digital? Since time immemorial, the great dream of human beings was to fly. The balloon was the first device which helped man to go up. It was made of paper and canvas then filled with hot air. Is this idea now a relic and obsolete? On the contrary. Thanks to an ultra-light helium balloon, Felix Baumgartner did the impossible. He rose to 39'045m in the stratosphere, then jumped off with a parachute and lived to tell the tale.

"MySound is a response to the needs of introducing modern electronic solutions into audiophile tube-tech components while maintaining their amazing old soul. The use of technologically advanced components, highly stabilized power supplies and modern design techniques allows us to bring out sonic aspects of vacuum tubes which had thus far been unexplored so that we can all hear more."

 … to be continued…