Closer Acoustics 300B Provocateur Signature Adam Sztaba integrated amplifier

 300B Provocateur Signature Adam Sztaba - a pursuit of excellence.

The top of the line version of Provocateur that together with Vigo EX Adam Sztaba Signature makes a system approved and signed for sound quality by Polish musician, conductor and arranger Maestro Adam Sztaba. 

Closer Acoustics does not offer many tube amplifiers. We focus exclusively on the 300B triode, and there’s a good reason for this. Our mission is to create the best possible Single Ended Triode amplifier using this particular tube. Why the 300B? Because, in our opinion — and not only ours — it is the queen of electron tubes, designed and developed nearly a century ago by the American company Western Electric specifically for sound amplification. When used correctly, this tube can deliver musical experiences at the highest level.

It is a low-power tube, rated at just 7 watts. Since our speakers, such as the Vigo, have high efficiency (97 dB), only a few watts are needed to reach full satisfaction. But these watts must be of exceptional quality. It’s not about quantity, but quality. When everything is perfectly balanced, the reward is an emotional and powerful musical message that can bring tears to your eyes and give you goosebumps while listening to your favorite music. You get dynamic range, energy, impact, and fine detail. But to achieve this, the tube needs the right conditions.

Let’s begin with the output transformers, which are paramount to the sound quality of any tube amplifier. The Adam Sztaba Signature version features two large amorphous core transformers, each weighing 3 kg. Using amorphous transformers reduces hysteresis and the effects of eddy currents on frequency response, which directly extends the frequency range. The high frequencies gain clarity and purity, while the increased cross-sectional area stabilizes and strengthens the low-frequency foundation.

Along with upgrading the output transformers, we enhanced the power supply by employing a transformer 30% more powerful, enabling more efficient energy delivery to the amplifier circuits. Naturally, changing the size and number of components required a redesign of the amplifier’s internal structure. The new Provocateur consists of 34 internal elements. In the highest-end version, all transformers are enclosed (“canned”) to minimize electromagnetic interference.

We managed to keep the amplifier’s footprint the same from above, but it had to grow slightly in height to fit the larger transformers. From the outside, this is visible as a bottom strip with embroidered lettering.

Next, we upgraded capacitors and resistors. In the audio signal path, we used some of the best—if not the best—audio capacitors currently available worldwide: the American-made V-Cap ODAM series. These reference-grade capacitors are specially selected with 1% accuracy and provide unmatched transparency, longevity, and exceptionally low noise levels.

Resistors come from Kiwame, Ohmite, and Amtrans. Kiwame resistors form the main elements in the power supply circuit, Ohmite resistors operate in the cathodes of the 300B tubes, and sensational carbon Amtrans AMRG series resistors are used in the signal path.

The increased size and quality of passive components required a redesigned circuit board, which now features gold-plated conductive paths on a thicker laminate for superior conductivity.

Audio signal RCA inputs have been upgraded with fine silver conductors from the WBT Nextgen series, as well as the speaker terminals. The power input socket is a top-grade NCF model from Furutech.

Finally, we refined the gain control by implementing a Khozmo resistor ladder on relays, fitted with high-quality Takman resistors. This remote-controlled ladder offers 64 positions and is calibrated to operate effectively from the very first step. Since a hallmark of good tube systems is the ability to enjoy rich, full-bodied sound even at low volumes—perfect for quiet evening listening—precise volume adjustment at low levels is essential.

Ultimately, our highest priority is customer satisfaction, because a component like this is chosen very consciously to be enjoyed for a lifetime.

Technical specification