Усилители мощности стерео — Kondo Audio Note Japan Melius

Kondo Audio Note Japan builds the Melius as a two-channel power amplifier that uses EL34 pentodes in push-pull rather than the single-ended triode output stages found in several other Kondo power amplifiers. The maker states that its push-pull topology was refined from the earlier Overture model and that the design targets modern loudspeakers.

Key specs that matter

Output is 32 W per channel into the 4 or 8 ohm taps at 1 kHz with 1.5 percent THD. Frequency range runs from 10 Hz to 70 kHz, measured at 1 W with the limits set at minus 3 dB. Inputs are provided on RCA and XLR sockets, both wired unbalanced, with an impedance of 70 kohm. Loudspeaker outputs are offered for 4 and 8 ohm loads, and residual noise is lower than 0.5 mV. Each channel is served by two EL34 output valves, one 12BH7 and one 6072, giving a total complement of four EL34, two 12BH7 and two 6072. Power consumption is 180 W. The chassis measures 438 mm wide, 204 mm high and 369 mm deep, and the amplifier weighs 26 kg.

Engineering and use context

Kondo couples the first stage directly to the driver stage, removing a coupling capacitor between them. Signal capacitors use pure silver foil and are mounted with vibration suppression. The output stage runs with a constant current bias circuit, which the maker calls CCB and describes as keeping the bias from being disturbed by the music signal. The circuit is designed for low impedance throughout. Internal wiring takes the shortest possible routes and uses SSW, the Kondo silk-insulated silver wire, with Ls-41 shielded cable where screening is needed. The output and power transformers are Audio Note's own, and all parts, from valves to wiring, were chosen through listening tests at the factory. Kondo states that the amplifier needs about 15 minutes after switch-on to reach its nominal performance.

Pairing

As the XLR socket is unbalanced, the Melius accepts any line preamplifier fitted with either connector type, and the 70 kohm input suits valve line stages. Kondo's G-1000i line preamplifier has a pair of RCA outputs plus an XLR output, so a single Melius or a second amplifier can be connected. The two output taps cover the common nominal impedances of passive loudspeakers.

Alternatives

The Kondo Ongaku, launched in 1989 with a copper chassis, is the brand's other stereo power amplifier, using a pair of 211 triodes in single-ended mode for 27 W per channel.