We are delighted to announce the new Ianus Ageto Triode Fet Gen 3 preamplifier

“Developed alongside the Ianus Geminea and Ianus Essentia Triode Fet power amplifiers, we can present the groundbreaking Ianus Ageto preamplifier. Further developing our Gen 1 Inverted Triode technology, we felt the Ianus Series deserved a rediscovering of the Inverted Triode possibilities and technology. For this purpose, we developed our Gen 3 Inverted Triode , to be used on this very special preamplifier.”



Gen 3 Inverted Triode

Our Inverted Triode technology, going back 13 years since early inception and prototypes , was mature enough to evolve to to new realms of performance.

The new Gen 3 technology not only sports a new Inverted triode tube, but also redesign of the circuits used and driving configuration.

Dual Chassis design

The main chassis , carrying all audio (non power) signal transformers benefits from completely separating the power supplies to different chassis. By isolating the power transformers, the very elaborate choke filter network and very high energy banks from the delicate signal transformers, achieves a noise floor unattainable by any tube pre-amplifier, and is a class on it’s own in terms of noise level, setting it self apart from other designs using signal transformers.

Signal transformers, such as output, TVC,and  inter-stage transformers, are sensitive receivers to any EMI and magnetic noise. The >120db noise floor of the Ageto is unmatched, even by tube equipment that do not use any transformers in the signal chain.

Transformer Volume Control

The Ageto preamplifier volume control is achieved by a system that uses multitap input transformer combined with latching relays.

Latching relays completely shields the design from possible contamination from relay driving currents.

The specially designed bifilar winded transformers are of highest quality to eliminate losses and maximize bandwidth,

Single Ended as well as true balanced inputs

All signal transformers use Nano-crystalline cores of the highest quality and performance.

Balanced outputs are possible as a custom option.

True Dual  Mono PSU

The Ageto is powered by a true dual mono external power supply. Each channel is powered by it’s individual power transformer and 8 independent choke filtered power supplies for each circuit of the Ageto. Multiple low and high frequencies inductors and careful layout provide extremely low noise supplies.

Each channel is fed by it’s individual PSU through it’s own high gauge umbilical cords.

Some words on Inverted Triode

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.This new method of electron flow control comes with some very interesting operating parameters and unique technical features, which we make of good use in our Inverted Triode circuits.

An example of the Inverted Triode’s technical advantage over a typical vacuum tube,ex 300B,is a comparison of the two  ,driving the same output transformer. The Inverted Triode tube presented a power bandwidth of 2Hz-500.000Hz where 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.

Technical Specifications



Gen 3 and Gen 1 Inverted Triode technology
(can use new Gen 3 technology or previous Gen 1 technology)

Number Gain Stages:


Tubes used:

1 x E280F(driver), 1 X Gen 3 IT (or Gen 1), per channel


Transformer volume control 26 steps

Channel Balance:

Balanced left/right function


HT bypass ready

AC Link:

Aries Cerat HT Link ready

Input impedance:

7kΩ <100Hz

Output impedance:


Signal bandwidth:

5Hz ~ 300Khz

Maximum voltage output:

2Vrms (low gain), 4V rms(medium gain)

Maximum gain:

3db (low gain version), 9db (medium gain version)

Noise floor:

<-120db unweighted


4 x RCA, 1 x true balanced XLR


550mm W x 430mm D x 165cm H


70kg (per chassis) 140kg total