Усилители мощности стерео — Kora CSA 2120

The CSA 2120 is the larger of the two stereo power amplifiers in the pure Class A range that Kora, the Toulouse electronics maker, unveiled at the Munich show in May 2025. The four-model family comes in small and large sizes, each in stereo and mono form, and the CSA 1200 monoblock is the bridged derivative of this chassis. In France the CSA 2120 is priced at EUR 28,200.

Key specs that matter

Rated output is 2 x 120 W into 8 ohm, all of it in pure Class A. Filtering totals 560,000 uF. For each channel there is an unbalanced RCA socket with 47 kOhm impedance and a balanced XLR socket with 20 kOhm impedance, and the left and right channels have their own gain potentiometers. Power draw is 280 W in normal operation and less than 15 W in standby. The case is 420 mm wide, 660 mm deep and 260 mm tall, and the weight is 45 kg.

Engineering and use context

A Square Tube stage built from two ECC82 and two ECC83 valves provides the voltage swing, and 60 output transistors supply the current. Because the output stage is designed as a current source that takes its signal from the transistor collectors, Kora says it ignores current fed back from the output filter or the speakers and stays stable on complex loads, even strongly capacitive ones. The link between the valve stage and the transistors is a voltage to current converter made purely of precision resistors, which Kora also credits with exact phase. In Class A the supply voltages are fixed and the current through the transistors varies around a constant quiescent value, so the chassis actually runs cooler when it delivers more power to the speakers. The user can therefore choose between nominal current for maximum output, half current for quieter listening, or an automatic mode that moves up to full current when the signal requires it. A slow pre-charge protects the mains from inrush surges, though peaks of 10 to 20 A can still occur. The display cycles through standby, valve heating, a greeting, running and goodbye screens, and in use it can show a table of values for each channel, which may differ slightly between the two sides.

Pairing

The separate channel gains let the amplifier compensate for small sensitivity differences between two speakers, and the balanced inputs suit the XLR output of the Kora PR140. Kora suggests flexible multi-strand speaker cable of large cross-section because current pulses can exceed ten amps.

Alternatives

The Kora CSA 270 is the smaller stereo model of the same Class A series, rated at 2 x 70 W into 8 ohm and priced at EUR 19,800 in France.