Усилители мощности моно — Vitus Audio SM-025

The SM-025 is a Class A and AB monoblock sold by Vitus Audio of Denmark as part of its Signature line. Vitus presents it as a step beyond the earlier SM-011 and says it delivers more power and a lower noise floor than that model. Each channel is housed in its own chassis, so a stereo pair means two separate monoblocks. A pair lists at EUR 55,000 in Europe, USD 68,250 in the US and AUD 100,500 in Australia.

Key specs that matter

On the rear of every chassis are an XLR socket and an RCA socket, each rated at 2 V RMS sensitivity with 10 kohm input impedance, plus one set of speaker terminals. Output is about 50 W RMS in Class A and about 200 W in Class AB into 8 ohm, rising to about 100 W in Class A and about 400 W in Class AB into 4 ohm. Output impedance is 0.075 ohm. With the input filter engaged, frequency response runs from 5 Hz to 100 kHz, and with the filter off it extends from DC to 100 kHz. Noise is specified as more than 110 dB below signal at 1 kHz and THD plus noise below 0.01%. Each chassis is 177 mm high, 435 mm wide and 436 mm deep, or 467 mm when the binding posts are counted, and weighs 38 kg.

Engineering and use context

Inside each unit sits a custom transformer with losses below 2%, feeding a capacitor bank of 180,000 uF per channel. Balanced circuitry runs from the input sockets to the speaker outputs, and the design uses zero global negative feedback. The Class A capability is one of the points Vitus uses to separate the Signature range from its Reference Series, whose amplifiers run as high-biased Class AB only. The design is derived from the SIA-030 integrated amplifier, but Vitus rescaled the chassis to improve airflow, protecting critical parts and reducing interference, and paid attention to internal shielding and layout. Body panels and heat sinks are both made of aluminium, and the three standard finishes are white, black and silver.

Pairing

Two units form a stereo pair. The balanced input suits a line stage with XLR outputs, while the RCA input accepts single-ended preamplifiers. In the Signature Series, the SL-103 Mk.II preamplifier and the SCD-025 Mk.II CD player are built in matching cases. Vitus states that the amplifier is meant to drive even the most demanding loudspeakers with confidence.

Alternatives

The Vitus SM-011 is the earlier Signature Series mono amplifier, with a 1.4 kVA UI transformer.