Усилители мощности стерео — Vitus Audio SS-103

The SS-103 is a stereo amplifier from the Signature Series from the Danish firm Vitus Audio. It was developed in parallel with the SM-103 monoblock and aims to give comparable results with both channels in one chassis. In the Signature power line it took over from the older SS-102, and it sits in that series beside the SS-025 stereo amplifier and the SM-025 and SM-103 Mk.II monoblocks. The user selects either class A or class AB bias and, separately, one of two voicing modes called Classic and Rock.

Key specs that matter

Output figures are given separately for each bias setting. In class A the amplifier gives about 50 W per channel into 8 ohm and about 100 W into 4 ohm, and in class AB the figures rise to about 100 W and 200 W. Each channel has one XLR and one RCA input, both with a sensitivity of 2 V RMS and an input impedance of 10 kohm. Output impedance is 0.075 ohm, and each channel has a single pair of binding posts for 4 mm plugs or spades. Vitus quotes bandwidth beyond 800 kHz, signal-to-noise above 100 dB at 1 kHz and THD plus noise below 0.01 percent. The amplifier stands 310 mm tall including feet, 435 mm wide and 601 mm deep, and weighs 85 kg. Power drawn from the wall is under 1 W in standby, 150 W in class AB and 300 W in class A.

Engineering and use context

Vitus describes a true balanced circuit, and any single-ended signal arriving at the RCA input is converted to a balanced one in the first input stage. Vitus selects and matches every transistor and uses super-precision resistors, and the local power supplies are shunt regulated, a section that was redesigned for this model to lower the noise floor. The mains transformer is a very large UI-core type. Construction is modular, so internal parts can be exchanged when upgrades appear instead of replacing the amplifier. Body parts and heat sinks are aluminium. Standard colours are white, black and silver, joined by three titanium tones - orange, grey and Dark Champagne.

Pairing

A preamplifier with balanced outputs, such as the Vitus SL-103 line stage from the same series, suits the XLR input. Because output doubles from 8 to 4 ohm in both bias modes, low-impedance loudspeakers are within its intended range, and the considerable weight needs a solid floor-level position rather than a rack shelf.

Alternatives

The Vitus Audio RS-101 is the two-channel power amplifier listed in the Reference Series, next to the RL-102 line stage.