Предусилители — Aries Cerat IMPERA II REF

The Impera II Reference is a tube preamplifier from the Reference Series of Aries Cerat, priced at GBP 24,950 in the UK. It uses four of the company's own Inverted Triode tubes and a transformer-based volume control, and it offers five unbalanced inputs with a balanced input and output as options. Its output voltage is enough to drive any power amplifier to full output.

Key specs that matter

Volume is controlled by an input transformer with 26 taps switched by sealed relays, wound bifilar. Maximum gain is 7 times and maximum output is 15 V RMS unbalanced, with a balanced output available as an option. The output stage has a bandwidth of 2 Hz to 500 kHz. There are five unbalanced inputs, a balanced input as an option, and a home theatre pass-through. The power supply is double choke-filtered, with four separate supplies and four capacitor banks. It weighs 110 kg unpacked.

Engineering and use context

The Inverted Triode is a tube developed by Aries Cerat, which the company says has a plate resistance a hundred times lower than a 6SN7, a common preamplifier triode. A low plate resistance gives a low output impedance, which helps the preamplifier drive long cables and power amplifiers with low input impedance. Using the input transformer as the volume control means the level is set by choosing taps on its winding, so attenuation happens in the magnetic domain rather than by a resistor. Bifilar winding, with two wires wound together, keeps the windings closely matched. The sealed relays protect the switching contacts from dust and oxidation. A double choke-filtered supply with four capacitor banks separates the supplies for different stages. The home theatre pass-through routes a surround processor's front channels to the power amplifier at a fixed level, bypassing the volume control. With its wide bandwidth, the output stage extends far beyond the audio range.

Pairing

The high output and gain let the Impera II Reference drive power amplifiers with low sensitivity, including Aries Cerat's Concero 25 with its standard gain of 1. The home theatre pass-through suits systems shared between music and film. The five unbalanced inputs leave room for a DAC, a phono preamplifier, a tuner and more.

Alternatives

The Aries Cerat Incito is the entry preamplifier of the brand, using two E280F tubes with transformer-coupled output and 32 V RMS maximum output.