Усилители мощности моно — Audio Note Gaku-On

Audio Note (UK) builds the Gaku-On as two separate monoblock chassis and names it the top of its mono amplifier range. Every chassis runs in pure Class A, with two 211 or VT4-C transmitting triodes sharing a parallel single-ended output stage, and the design meets all the criteria of Audio Note Level 5, the highest grade of materials and parts in the catalogue. In the current mono range it belongs to the 211 parallel single-ended group together with the Ankoru II and the Ginrei.

Key specs that matter

Output is approximately 45 W per channel into 4 or 8 ohm loads. The input is an XLR balanced line connection with an impedance of 2.4 kOhm, and the two chassis match in level within 0.3 dB. A pair therefore delivers stereo from two identical boxes, one per side. A stereo pair holds four 5R4WGB rectifiers, four 211 or VT4-C output triodes and two VT25 or 10Y driver triodes, which works out to two rectifiers, two output valves and one driver per chassis. Each amplifier weighs 40 kg and measures 305 mm high, 305 mm wide and 640 mm deep per chassis, with a maximum draw of 200 W from a 100-120 V or 220-240 V supply at 50 or 60 Hz.

Engineering and use context

The two 211 valves in each chassis work in parallel in a single-ended stage, which raises the available power above that of a single 211 while keeping the single-ended topology. The amplifier uses no negative feedback, rectifies its supply with valves and runs the triodes with direct heating. No coupling capacitor sits anywhere between input and output. Each stage has its own silver wired transformer instead, three in total per channel. Parts listed for the Level 5 build include Black Gate capacitors, Audio Note silver foil capacitors, tantalum resistors, silver wire with the finest core materials for all transformers, and silver signal wire throughout the circuit. The company states that the design was engineered for sonic performance rather than for technical specification. Standard finishes are anodised aluminium, black anodised aluminium and copper, and custom paint can be ordered.

Pairing

With its balanced input impedance, the Gaku-On expects a preamplifier with balanced outputs able to drive that load. Two chassis are needed for stereo.

Alternatives

The Audio Note Ginrei is another mono power amplifier built with 211 triodes in parallel single-ended form.