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Virtus-01 with Ayon Audio tubes.
Tube rolling brought some benefits but also proved that many basic features of the White Bird amp would stay put regardless of what tubes were used. The Ayon tubes improved depth, resolution and richness. Now the sound had become even more sophisticated. I could feel it even more in my gut. The extent of  change was noticeable but not a game changer.

Even so I really appreciated the improvements when I reverted to the stock Electro-Harmonix. It became even clearer that the Ayons had produced more depth, richness and sophistication. With them the sound really was excellent. They confirmed what I had already identified – a slight emphasis of part of the upper midrange and great grippiness in the bass as two core qualities for the Polish headfi amp. The Virtus-01 is a very mature product and one of the best headphone amps I’ve run into. There is still room for improvement but once you simply listen you don’t really feel any improvements are necessary.

Test methodology. I compared this amplifier with three others: Leben CS-300 SX custom version, Synergy HiFi 6F3 and Triode TRV-A300SER. I used the HiFiMan HE-500, Sennheiser HD800, AKG K701 and Beyerdynamic DT-990 Pro headphones. The HifiMan and Sennheiser used the Entreq Konstantin 2010 cable.

The amplifier was placed on an Acoustic Revive TB-38 platform. Cables were Purist Audio Design Corvus interconnects. I did A/B tests where both A and B were known. I used 2-min. music samples and whole albums. Apart from my Lektor Air V-edition CD player as main source, I also used the AMG Viella12 turntable with a Benz-Micro LP cartridge and Manley Chinook phono stage.

Description. The Virtus-01 is a tube headphone amp with solid-state power supply. The enclosure is built of granite slabs on the top and sides with an acrylic front, plastic back and aluminium bottom. There’s a volume control knob on the front with a red power LED above it, a mechanical on/off switch and headphone socket. On the back panel are two pairs of RCA inputs and a power inlet. On the top cover sits a nice brass plaque with the manufacturer's logo and gold-plated dress rings around the tube sockets.

Unfortunately I could not open this amp up. It was put together so cleverly that I simply couldn't risk damaging it with any crude attempts at entry. I can say only what I saw through the sockets and what the manufacturer mentioned. I could see that the circuits spanned a few PCBs and that there were two separate power transformers. I couldn't see an output transformer to think this might be a capacitor-coupled OTL design. The volume control is an Alps pot and all internal connections are made with pure copper.

Technical specification according to manufacturer:
  • Power consumption: around 50VA
  • Input impedance: 24Ω - 600Ω (optimal 220Ω)
  • Frequency response: 12Hz-75kHz
  • Output power: from 2 x 200mW to 350mW depending on input impedance
  • Distortion across audible range at 120mW output power: < 0,5%
  • Optimum driver voltage: 1.5-2.5V
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