Aries Cerat Impera II Reference Preamplifier – 240V

The Impera II preamplifier is a showcase of our unique Inverted Triode Technology, a vacuum tube technology innovation developed by our company and utilized in the Impera II series of audio designs.

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 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, the inverted triode, actually acts like a virtual “vacuum state transformer”. Instead of having gain, the inverted triode has a gain that of 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.

An example of the Inverted Triode’s technical advantage over a typical vacuum tube, for example the 300B, is a comparison of the two, driving the same output transformer. The Inverted Triode tube presents a power bandwidth of 2Hz-500.000Hz where as the 300B tube had a bandwidth of 15Hz-100.000Hz. Same transformer, same driver tube, but 5 times the bandwidth for the Inverted Triode tube.

The output stage is driven by the input tube with the help of an amorphous Double-C Core signal choke. The output stage is driving a highest quality Double-C Core output transformer, with bifilar winding techniques, giving the transformer supreme frequency extension and supreme transient signal response parameters.

Signal attenuation is achieved with a uniquely designed multi-tap input transformer, which has special bifilar winding as well ,resulting in excellent performance both in frequency and time domain. The 26 separate taps are switched by small signal sealed relays. All four vacuum tubes are fed by special quality PSUs, with four individual choke filtered capacitor banks.