Усилители мощности моно — Trafomatic Audio Elysium

The Elysium is a single-ended monoblock power amplifier from Trafomatic Audio, built around one Eimac 250TL direct heated triode per chassis. Operation is pure Class A up to 20 W, after which the single triode continues into Class A1.

Key specs that matter

Input sensitivity is 3.5 Vrms and input impedance is 47 kOhm, with both RCA and XLR input sockets fitted. Speaker outputs are provided for 4 and 8 ohm loads. Distortion is 0.3% at 1 W and 1 kHz. The frequency range extends from 10 Hz at minus 2 dB to 60 kHz at minus 3 dB. Each unit draws 500 VA from the mains and is supplied for 230 V at 50 Hz as standard, with 100, 120, 220 and 240 V versions available on request. Dimensions are 620 x 520 x 800 mm and weight is 85 kg per monoblock.

Engineering and use context

Inside each chassis the valves are two EML 20B-V4 driver triodes, one EML 5Z3 rectifier and the Eimac 250TL output triode. The link between the stages is unusual - the 250TL is coupled directly to the 20B-V4 through an unconventional interstage transformer, part of what Trafomatic calls its pure Class A DHT single-ended circuit. The high-voltage supply is rectified by the 5Z3 valve. Both the 250TL and the 20B-V4 drivers are direct heated triodes. A soft-start circuit was designed specifically for the 250TL to limit stress on its filament each time the amplifier is switched on and off, and the amplifier needs an extended warm-up period before use. Trafomatic notes that no standard transformers exist for this application, so the company acquired its own winding machines to build prototypes and final units in house rather than rely on outside suppliers. The wood and glass cover sits over the exposed valves and protects them while the amplifier is running.

Pairing

Two chassis are required for a stereo system, one per loudspeaker, and each needs its own mains connection. Every monoblock is supplied with its own power supply section, rectifier valve and interstage transformer rather than sharing them. The XLR input accepts a balanced preamplifier directly, and the RCA input serves single-ended line stages. Speaker cables go to whichever output tap suits the loudspeaker.

Alternatives

Trafomatic Audio also makes the Pandora, a push-pull Class A monoblock using a pair of Svetlana 811-10 direct heated triodes and rated at 40 W in pure Class A per chassis, with a balanced XLR input only, 28 dB of gain and a weight of 32 kg per unit.