Усилители мощности моно — Ayon Audio Ayon Orthos Evo

The Orthos Evo is a single-channel tube power amp built by Austria's Ayon Audio, one of four mono models in the maker's EVO amplifier line. A stereo setup therefore takes a pair of chassis. It is a fully balanced design using KT150 or KT170 output tubes and can be switched between triode and pentode operation. Ayon lists newly designed operating and protection boards, all-new mains transformers, revised chokes and a reworked bias circuit.

Key specs that matter

With KT150 tubes Ayon rates the Orthos Evo at 1 x 250 W in pentode mode and 1 x 170 W in triode mode, for 4 and 8 ohm loads. Frequency response is 12 Hz to 60 kHz, and bandwidth is 8 Hz to 70 kHz. The amplifier needs 1000 mV for full power, input impedance at 1 kHz is 47 kOhm, and S/N at full output reaches 98 dB. Negative feedback is 0 dB. RCA and XLR inputs are provided, with WBT NextGen binding posts for the speaker cable. Each unit is 35 cm wide, 61 cm deep and 25 cm tall, with a mass of 52 kg.

Engineering and use context

A new coil technology in the output transformer is meant, in Ayon's words, to keep the amplifier more stable at low frequencies. Gain and driver stages and the ground system were redesigned for a shorter, more direct signal path, free of transistors, follower stages or buffers. The supply combines two separate insulated power transformers, in damped enclosures screened from RFI and EMI, with dual chokes for the power tubes and a further choke for the input and driver stages. Each amplification stage has an isolated supply, input and driver tube heaters have their own high-current regulators, and heaters are fed with regulated, soft-started DC. An AC line filter, in-rush limiting and a sequenced start that completes in 1 minute help extend tube life, alongside a protection system for the power tubes. For earthing there is a one-point star layout and a dual system chosen with a ground switch. The tube holders are bespoke parts with beryllium-copper contacts, XLR sockets come from Neutrik, and the circuit boards are gold plated. The anodised aluminium chassis is hand assembled, with a bias meter, engraved front and rear legends, aluminium feet and an illuminated maker logo, offered in black or chrome.

Pairing

A preamp with balanced outs can use the XLR socket, and the maker rates it as fit for harder-to-drive speakers as well.

Alternatives

Ayon's EVO mono range also includes the Epsilon Evo Mono.