A new way of using triodes is born, in fact you can say it is a whole new active component

“The Impera II Signature is our grand statement of what we believe to be the absolute best preamplifier on the market. Further advances from the already remarkable Impera II preamplifier include the use of our Gen 2 Inverted Triode technology, upgraded quad choke filtered power supplies, improved inductive coupling between stages and a new proprietary circuit for input stage biasing. …prepare to be surprised.”


A new way of using triodes is born, in fact you can say it is a whole new active component. A component that gives the Impera preamplifier extra-ordinary performance, unrivalled by any tube or transistor preamplifier stage.

The Impera II preamplifier is a showcase of our unique Inverted Triode Technology, a vacuum tube technology innovation developed uniquely by Ariues Cerat and utilized in the Impera II series of preamplifiers.

The Inverted Triode is a unique active element, widely different to any kind of vacuum tube used in audio and tube electronics in general. Three electrodes, a cathode, grid and plate are combined to give an amplification device completely different in operation than the classic vacuum tube.


Inside a typical vacuum tube, an electron stream emitted from a heated cathode is accelerated toward a positively charged anode, which has a flat plate structure. The electron flow is impeded by the grid, a negatively charged wire-grid structure, placed between the cathode and anode. This operation resembles a typical fluid control valve, hence the name valve tube.

Inside an Inverted Triode tube, the electron stream emitted from a heated cathode is accelerated towards the anode, now a wire-grid-like structure. The electron flow is thus now unimpeded since no grid structure exists between the anode and cathode. Instead, a plate-like structure enveloping the cathode/anode assembly (called the control “grid”) is shadowing the anode electrical field, having a very high negative electrical field itself, thus “pushing” the electrons away from the anode.

This mode of electron flow control is completely different than a triode mode of operation.
The parameters of this new active element behave very differently than a conventional triode; the inverted triode actually acts like a virtual “vacuum state transformer”. Instead of having gain, the inverted triode has a gain that is a fraction of unity, just like a step down transformer. The internal resistance is many times lower, and input capacitance is nearly zero.

The extra-ordinary parameters of the inverted triode used (100 times lower plate resistance than a 6SN7 tube, zero input capacitance) gives the output stage unrivalled measured performance: 2Hz-500KHz bandwidth, figures unreached by any triode – transformer output stage.

The Impera Sig circa 2020, is the first Impera Series to fully exploit the possibilities of our second generation Inverted Triode technology. Using all of our data and lessons learned in the 10 years researching and using the IT (Inverted Triode) technology, we took some steps into further improving the technology, both in measurable (objective) and sonic (subjective) aspects.

The main difference of the Gen 2 to Gen 1, is the use of dual IT(Inverted Triodes) in parallel mode, while working on very different operating conditions that Gen 1 IT. This further improved the distortion, noise and IM figures, while bandwidth almost doubled ,even if by using the same passive components( ex, the output transformer).

Moving the OP(operating point) to new ,previously unusable regions, allowed us to lower the grid (plate) consumption thus improving IT life as well. The Gen 2 technology also includes different biasing/driving circuits. The driving/bias stage is now a stacked/folded configuration, further improving bandwidth, stability and transient response. In short, the Gen 2 IT technology is a complete redesign and rethought process of the IT  technology, which was time to get a step even further.

What are the differences between the Impera Reference and Impera Signature versions?

Impera II Ref uses a small external transformer case for the PSU

Impera II Sig uses a full sized second chassis for the PSU

The Power Supply

Beginning with the power supply. The external full sized chassis, includes 10 totally independent power supplies, each rectified, filtered and stabilized. Extensive use of chokes (10 in number) is used, in combination of special quality capacitors. 

The newly developed Gen 2 IT circuits resulted in tripling the demand for independent PSUs. The 500VA encased transformer feeds all the (mirrored for each channel) 10 power supplied, and are fed via double umbilical cords to the main signal chassis, for complete magnetic and EM isolation.

The Signature Impera shares almost no common parts to the Reference design. The output transformer is redesigned using nano-crystalline cores, and uses now winding technology. The signal chokes are higher grade and do present half the parasitic capacitance of the previously used inductors.

The volume control is using our trusted TVC technology (transformer volume control) and is using slightly different tuned secondary loads.

The driver/ bias and IT supplies make extensive use of high speed low ESR capacitors.

All four heater supplies are triple filtered.

The sound or non-sound of the Impera II, is a brand new experience in the audio world, and is achieved by radical new solutions, created after out-of the box research and testing.

Technical Specifications


Maximum gain:

x5 (14db) High gain version. x2.5 (8db) medium gain version

Output stage bandwidth:

2Hz - 500KHz

Attenuation method:

Multi-tap input transformer

Power supply:

Full sized chassis, 10 independent PSU, 500VA


4 unbalanced, 1 x true balanced


RCA, AC link, XLR (on demand) 10Vrms ( High gain version)

Weight unpacked:

110kg total