Thrax Spartacus Amplifier

A masterpiece demonstrating how modern thinking applied to Directly Heated Triodes with advanced magnetic materials and a classic concept eclipses all other approaches.
It is an engineering overkill in all aspects based on the legendary Western Electric 300B tube.
It used six 300B tubes in 2 stages and delivers 50W of pure class A triode sound.

FEATURES OF THRAX SPARTACUS

Custom current production tubes for long life
50W for ample power reserves
Low noise for subtle dynamics
Auto bias for compensation of tube ageing and correct operation of any 300B
Current sourced 300B Shunt regulator for stable power allowing explosive dynamics and transparency even on the hardest loads
Transformer input and output for galvanic isolation
Microprocessor controlled operation for safety
Special filament heating circuit for harmonic richness and tube protection
Highest quality torque binding posts protecting your cables

50 WATTS OF PURE 300B AMPLIFIED POWER

The Thrax Spartacus amplifiers input is a 300B tube and it drives 4x300B tubes in the output stage. There is also a shunt regulator based on yet another 300B tube that makes sure all signal currents go through 300B tubes with no capacitor in sight.

Now for the first time you can actually hear what a 300B really sounds like and prepare to be amazed. Complimented by the finest nano-cystaline core output transformer and nano-crystalline choke power supply it really redefines tube amplification.

The Spartacus amplifier features one of the simplest possible signal paths with absolute zero feedback (wire-vacuum-wire-vacuum-wire). To achieve simplicity while delivering exemplary performance, each device in the signal path had to be the best possible.

WHY THE 300B WAS CHOSEN FOR THE THRAX SPARTACUS AMPLIFIER

Its because they are the most linear amplifying devices and some of the very best audio tubes ever made. It is a fact that the distortion of triode vacuum tubes compared to solid-state devices is orders of magnitude lower. Apart from the low distortion level, the type of distortion they produce is a consonant 2nd harmonic only. To go further we employ a technique to cancel the negligible distortion they would generate by running two of them out of phase effectively canceling each other’s distortion.
For this to work we designed a driver stage that would supply the two output tubes with exactly the same signal in phase for one and out of phase for the other by using another 300B.

The Spartacus amplifier is loaded with a perfectly symmetrical phase split transformer with independent windings and screening providing separate bias to the output tubes preventing any interaction.

Our proprietary ultra low noise current sourced shunt regulator makes sure nothing moves unless it is supposed to. Not a popular approach at the voltages and currents involved as is extremely difficult to make. But infinitely rewarding when done. The most 300B tubes have considerably low voltage gain, so a step-up input transformer takes care of that. Look no further as there is no commercially available product coming close to Spartacus 300.

TECHNICAL SPECIFICATIONS

Input

1 balanced XLR connector

Output Power

50W pure class A

Power supply

115 or 230V

Power consumption

450W

Weight

55 Kg

Dimensions