Усилители мощности моно — Kora CSA 1150

The CSA 1150 is a single-channel pure Class A power amplifier from Kora, the French company set up in Toulouse in 1990 by François Philibert. In its early years Kora worked for Aérospatiale and sold amplifier kits, and in 1994 it released its first integrated amplifier, the Design 30. The firm stopped trading in the early 2000s, and Bruno Vander Elst revived the name in 2017 in Portet-sur-Garonne near Toulouse, where the amplifiers are built. The CSA 1150 was one of four Class A models first presented at the Munich show in May 2025, and it is the monoblock version of the CSA 270 stereo amplifier, housed in the same case. It is priced at EUR 19,800 per unit, so a stereo system needs two.

Key specs that matter

Rated output is 150 W into 8 ohm, delivered in pure Class A. The linear power supply carries 400,000 µF of filter capacitance, four times the 100,000 µF of the biggest earlier Class AB amplifier from Kora. Connection is by a single RCA or a single XLR input. The speaker terminals do not support bi-wiring. The aluminium and steel case, finished in Mineral grey, measures 420 mm wide, 440 mm deep and 260 mm high, and the amplifier weighs 32 kg.

Engineering and use context

Every Kora amplifier is built on Square Tube, an operational amplifier circuit developed by Vander Elst and protected by a patent. Two ECC82 and two ECC83 valves are arranged symmetrically and drive the transistors directly, so the valves define the signal voltage while the transistors supply the current the loudspeaker draws. The circuit runs from asymmetric rails of +300 V and -200 V. The valves are monitored continuously, a display warns if one fails, and their expected service life is about 20 years. Heat from the Class A output stage is carried away by heat sinks on both sides of the case. The unit switches itself on when a signal arrives and off when the input stays silent, and it can drop to a lower bias current when the loudspeaker impedance allows.

Pairing

The CSA 1150 has no volume control, so it needs a preamplifier, and Kora's own PR140 with five inputs is the in-house option. With XLR on board, a balanced preamplifier can be connected directly. The Class A power of each chassis leaves reserve for less efficient passive floorstanding and stand-mount designs.

Alternatives

The Kora CSA 1200 is the larger mono model, rated at 200 W in Class A with 560,000 µF of filtering in a 660 mm deep case weighing 45 kg.