Интегральные усилители — MOREaudio CS100

The CS100 is an integrated amplifier from MOREaudio, a Polish company run by MORE technic Sp. z o.o. in Zabrze. It was founded by Tomasz Dębski, its chief designer, a guitarist who previously designed effects units and controllers at G-lab, and Jan Siwy, an electronics designer and computer scientist with a background in producing electronic devices. The CS100 is the company's first product and currently the only one it sells, priced at EUR 4,900 in the maker's own shop, which also runs a home trial and rental scheme for listening before purchase.

Key specs that matter

Rated output is 100 W RMS per channel into 8 ohm and 200 W RMS into 4 ohm, so power doubles as the load halves. The frequency response runs from 5 Hz to 120 kHz within 1 dB, and THD+N is 0.05%. There are four unbalanced RCA inputs with an input sensitivity of 600 mV peak to peak and an input impedance of 100 kohm. The stated output impedance is minus 150 milliohm, a negative figure. The chassis measures 340 x 180 x 330 mm and weighs 15 kg.

Engineering and use context

Dębski describes the circuit as a new topology inspired by single-ended amplifier designs. The signal passes through four two-stage blocks, all built in single-ended form and each with its own local feedback, and there is no global feedback loop around the whole amplifier. The maker's aim is to reduce transient intermodulation distortion, which can arise when a single loop spans many stages. Its final stage works in class AB yet keeps single-ended topology solutions, trading the heat and power draw of class A for higher efficiency. It combines positive and negative feedback, and this mix is what gives the amplifier its negative output impedance. Level control uses a resistor ladder switched by analogue switches, from 0 dB down to minus 64 dB in 1 dB steps, which keeps distortion low across the whole attenuation range. An LED display shows the selected input and the volume level. The CS100 is a pure line-level amplifier, with no DAC, streamer, phono stage, Bluetooth receiver or headphone output.

Pairing

Because every input is analogue and unbalanced, the CS100 needs an external DAC or streamer with RCA outputs, a CD player, or a separate phono stage for vinyl. Its power into low impedances makes it usable with demanding floorstanding speakers as well as with easier stand-mount designs.

Alternatives

MOREaudio has no other integrated amplifier, since the CS100 is the only model in its catalogue.