Усилители мощности стерео — Trafomatic Audio EOS

The EOS Power Amp is a two-channel dual mono power amplifier with valves throughout, made by Trafomatic Audio, whose class AB push-pull output stages develop 100 W into each channel. Its power supply lives in a separate enclosure linked to the main chassis, so the transformer and filter parts are kept away from the audio circuits. The European price is EUR 8,999 including tax, with a delivery time of up to four weeks.

Key specs that matter

Signal enters through RCA or XLR sockets with 24K gold plated contacts, and the speaker outputs are tapped for 4 and 8 ohms. Sensitivity is 1 V rms and input impedance is 100 kohm. Distortion is quoted as 0.03 percent at 1 W and 1 kHz and 2 percent at full output. Frequency bandwidth reaches from 10 Hz to 100 kHz, both limits given at -1 dB, and signal to noise is 82 dB. The amplifier chassis measures 450 x 350 x 230 mm and weighs 25 kg, while the supply box is 150 mm wide, 300 mm deep and 200 mm high at 11 kg. Consumption is 500 VA, and the mains voltage switches between 230 V at 50 Hz and 115 V at 60 Hz.

Engineering and use context

Per channel there is a pair of Tung-Sol KT120 output tetrodes, with two ECC99 and two 5687 double triodes handling the input and driver duties across the two channels. The dual mono layout keeps left and right signal paths separate, and cathode feedback is applied in the output stage. Output transformers are built on double C-cores, and the maker specifies Solen fast capacitors. In the external supply an 800 VA toroidal transformer feeds C-L-C filters that are separated for each channel, so the two sides draw from independent reservoirs. Together the two boxes weigh 36 kg, and the transformer rating leaves a margin above the amplifier's consumption. An acrylic front glass covers the valves and protects them from accidental contact.

Pairing

A preamplifier with volume control is needed in front, and the XLR input lets a balanced preamp connect directly, while RCA covers single-ended units such as the Trafomatic Evolution Line One. With its power reserve and two output taps, the EOS can drive conventional floorstanding speakers of average sensitivity, not only high-efficiency designs. Space for two boxes and good ventilation around the valves should be planned.

Alternatives

The Trafomatic Evolution Elegance is a smaller stereo valve power amplifier with four 6550 (KT88) tubes and 2 x 50 W output.