Интегральные усилители — Closer Acoustics 300B Provocateur

The 300B Provocateur is a valve integrated amplifier using an SET output stage, made by Closer Acoustics, the Polish maker from Katowice best known for its high-efficiency single-driver loudspeakers. It uses a pair of 300B output tubes working in Class A and is built by hand, with a Standard version and a Signature version that adds amorphous core output transformers.

Key specs that matter

Output is 8 W per channel. The tube complement consists of one 5U4G rectifier, two 6SN7 tubes in the driver stage and two 300B triodes in the output stage. The published bandwidth is 18 Hz to 23 kHz within 2 dB, total harmonic distortion is 0.3% measured at 1 W, input sensitivity is 200 mV and channel separation exceeds 70 dB. Four line-level inputs are provided, all RCA on the standard build, while the Signature can be ordered with XLR sockets instead. The chassis measures 40 cm in width, 45.5 cm in depth and 19.8 cm in height without tubes, or 32.5 cm with the tubes fitted, and it weighs 28 kg. The Signature Edition was priced at EUR 7,915 before taxes on its introduction, and a later list price for it stands at EUR 8,907.

Engineering and use context

Polypropylene capacitors are used both in the signal path and in the power supply, and electrolytic capacitors appear only in the heater circuits. Volume is set by a 48-step motorised stepped attenuator, which can be operated from the supplied remote handset. The remote controls volume only. Speaker outputs use pure copper binding posts that accept banana plugs, spades and bare crimped cable ends. The amplifier is housed in a multi-layer wood cabinet, and an Alcantara finish is among the custom options offered. It runs on 230 V mains, with a 110 V build available on request. The single-ended topology means each channel uses one 300B running without a push-pull partner, and the amorphous core transformers of the Signature are the main hardware difference between the two versions.

Pairing

With such modest output, the amplifier is intended for high-efficiency loudspeakers. Closer Acoustics presented it alongside its Forlane floorstander, rated at 94 dB, and the brand's Allegra and Vigo models are also voiced with SET amplification of this kind in mind. Low-efficiency speakers with difficult impedance curves are a poor match.

Alternatives

Closer Acoustics does not list any other integrated amplifier model, offering the 300B Provocateur only in its Standard and Signature builds.