Усилители мощности моно — Audio Note P4 Balanced Tonmeister

Audio Note (UK) sells the P4 Balanced Tonmeister as two monoblocks, one enclosure per channel. Every enclosure holds two 300B directly heated triodes working in pure Class A as a parallel single-ended pair, and the design meets the Audio Note Level 3 criteria. The company describes these as substantial monoblocks aimed at owners who prefer not to have exposed valves. In the current mono range they belong to the 300B parallel single-ended group with the Conquest, Kassai and Kegon.

Key specs that matter

Maximum output is 18 W RMS per channel into 4 or 8 ohm loads. The input is a balanced XLR connection with an impedance of 2.4 kOhm, with 1 V needed for full output. Channel balance stays within 0.3 dB either way. Across both chassis the valves are two 5U4GB rectifiers, four 300B output triodes and two 5687 double triodes, so each chassis holds one rectifier, two 300B and one 5687. Each amplifier weighs 28 kg and measures 220 mm high, 460 mm wide and 530 mm deep. Mains input is 100-120 V or 220-240 V at 50 or 60 Hz, and maximum consumption is 200 W.

Engineering and use context

The balanced signal goes straight into an input transformer. An interstage transformer then links the 5687 dual triode to the pair of 300B valves, which work in parallel single-ended mode, so the amplifier has no capacitor coupling anywhere in the signal path. Audio Note says this approach cuts the number of parts the signal passes through and simplifies the circuit. Zero negative feedback, valve rectification and directly heated triode operation complete the Level 3 list. The input and output transformers have hand-wound copper primary and secondary windings. The output transformer cores are a Double C design made from the company's own SHiB material and wound in-house in the U.K. The fascia is anodised aluminium, with a black acrylic option.

Pairing

A preamplifier fitted with XLR outputs connects directly. A single-ended preamplifier can also be used with the correct cable, provided it can drive the low input impedance. One chassis serves each loudspeaker. Each pair is built to order, with a build time of about 8 weeks.

Alternatives

The Audio Note Conquest is a mono power amplifier that also runs 300B valves in a parallel single-ended stage.