Усилители мощности моно — Kora CSA 1200

The CSA 1200 is the large monoblock in the pure Class A family that Kora of Toulouse first showed in Munich in May 2025, a range of four models designed under technical director Bruno Vander Elst. It is the bridged, single-channel version of the CSA 2120 stereo amplifier and shares that model's case, and a pair costs about EUR 60,000. Kora offers the family in two sizes, each as a mono or a stereo unit.

Key specs that matter

One channel delivers 200 W into 8 ohm in pure Class A. The power supply carries 560,000 uF of filter capacitance. Each unit has a single RCA input at 47 kOhm and a single XLR input at 20 kOhm, chosen by a switch at the rear, with a gain potentiometer marked between 0.5 V and 2 V. The case measures 420 x 660 x 260 mm and weighs 45 kg, finished in mineral grey over aluminium and steel. A power cord and manual are the only accessories.

Engineering and use context

All voltage gain is produced by the Square Tube stage with two ECC82 and two ECC83 valves, while the output stage is a Class A transistor section that works as a current source. Kora states that pure Class A here follows the strict definition - the signal is taken from the collectors, and the devices are biased at the middle of their range so they stay linear, which in practice moves crossover distortion to the point of clipping. The large versions use 60 output transistors. A converter built only from precision resistors, with no semiconductors, passes the signal from the valve stage to the power section. Two bias levels are available - the nominal current for full output and an economy setting at half that value. In AUTO the amplifier idles at the lower current and jumps to the higher one when a loud passage demands it, dropping back after about ten seconds. The large capacitor bank is charged slowly over a few minutes, and two green LEDs on the filter board confirm when it is ready. A small lamp at the back shows if the mains phase is reversed. The front has a display and one knob that selects and confirms functions.

Pairing

Each CSA 1200 drives one loudspeaker, so stereo use requires two of them driven by a preamplifier such as the balanced output of the Kora PR140. A rear switch flips signal polarity by 180 degrees for multi-amplified setups. With the power switch on AUTO, the amplifier switches on as soon as it detects an input signal and goes back to standby once a minute passes without one. Kora asks for free air on all sides, and the terminals accept 4 mm banana plugs or bare wire.

Alternatives

The Kora CSA 1150 is the smaller mono model of the same Class A family, rated at 150 W into 8 ohm with 400,000 uF of filtering.