Virgo Preamplifier

The Design Concept

The Virgo is based on a extremely elaborate small Single Ended Triode amp design, using a pair of triode-strapped E280F supertubes per channel.

The main power supplied, bias supplies and signal transformers are specially design not to impede with the circuit performance.

The main idea of parallel triode single ended preamp is simple, however the Virgo is an example of how a simple circuit sounds when implementation is a true cost no object approach.

The Output Stage

The output stage is a dual parallel single ended triode(SET) circuit, using dual E280F supertubes per channel.

This SET circuit uses a special quality nanocrystalline-core bifilar output transformer, for supreme linearity and bandwidth. The output stage local power decoupling is using a massive film capacitor with extreme specifications (max current delivery 10000A and ESR of 1.5mOhm!) which makes it virtual transparent.

The combination of the output transformer, psu, bias system and tube compliment, make this circuit present an unprecedented dynamic headroom for a line level preamp. It’s maximum voltage and current swing is 30-100x more than any amplifier, low or high gain, will even require.

The biasing system

The biasing system, is an elaborate system, which begins with tube rectifiers for the negative voltage supply, super film capacitors throughout, choke filtration and double trimmed adjustments, for each channel.

The bias system provides a superbly clean noiseless negative bias to the output stage, to sustain a lowest possible noise floor.

The bias system can be monitored and adjusted on the fly, using the internal dual meter/monitors.

Volume Control

As with all our preamps, the volume control is implemented using a specially winded multi-tap input transformers.

Volume contro/attenuation is achieved selecting which tap of the secondary is active, using an array of ultra low noise latching relays. These relays are active only when they change state, and power down when not changing state, eliminating noise bleed through the control system, to the signal.

The Power Supply

The power supply is fully a dual mono tube rectified unit.

The high voltage rails are powered by a xenon-rectifier bank. Xenon rectifiers are the closest thing to a mercury vapor rectifiers, without the drawbacks and risk of using mercury vapor rectifiers. These extremely high current xenon rectifiers,have solid state-like current delivery and very low sagging, while have zero switch noise when properly implemented.

The negative bias circuits are powered also by a tube rectifier, using the 6AU4 damper diode. This solution give the lowest possible noise floor to the critical negative bias section.

No electrolytic capactitors are used throughout the unit as well the local decoupling capacitors in the main unit.

Instead, we use a special breed of film SuperCapacitors. For reference purposes, the local capacitor bank in the main unit, has a max surge capabilities of 30000Amperes . Of course these specs are nowhere near any audio circuit will demand, however this is a testament that the ESR an ESL ratings of the capacitors are a few magnitudes lower than any capacitor used, making these PSU capacitors truly invisible to the audio signal.

These special SuperCapacitors are used in the main PSU rails as well as the negative bias circuits.

The Xenon rectifier

The Xenon rectifier banks used for the high voltage rails, and the damper diodes used in the negative bias supply, provide the lowest noise floor possible with extremely high current delivery /low sagging.

The QuintEssence mirrors

The QuintEssence mirrors the strengths of a SOTA Single Ended tube amplifier, with superbly accurate timbre and a huge soundstage