Интегральные усилители — Circle Labs Audio AS100

The AS100 is a transistor integrated amplifier from the Polish company Circle Labs, which presented it together with the M500 hybrid power amplifier during the Warsaw Audio Video Show held from 24 to 26 October 2025. It uses the same Circle Power topology as the M500.

Key specs that matter

Circle Labs lists output as 65 W per channel into 8 ohm and 110 W into 4 ohm. Frequency response extends from 3 Hz to 500 kHz at the -3 dB points, and the damping factor exceeds 250 into 8 ohm. Power draw is under 0.1 W in standby, 50 W in normal operation and up to 300 W at maximum output. The fuse complement is one T5A, two T2A and one T400mA.

Engineering and use context

Circle Power is the company's own amplifier topology, described as combining features of asymmetrical and symmetrical circuit designs. The input stage uses ultra-low-noise Burr-Brown J-FET transistors, and bipolar transistors carry the output stages, so the sensitive voltage input and the current-delivering output use different device types. Construction follows dual-mono lines, every channel drawing on its own 400 W toroidal transformer, and the power supply holds a total of 200,000 microfarads of filter capacitance, which the maker links to low distortion and compatibility with many loudspeakers. Level is set by a precision resistor ladder of 63 steps built from parts with 0.1 percent tolerance and switched by high-grade signal relays instead of a conventional potentiometer, which the maker says keeps channel balance precise and holds up over long use. A remote control handles the main functions.

Pairing

Able to drive difficult loads with firm control, the AS100 is aimed at conventional passive loudspeakers across typical impedance loads, including 4 ohm designs, in a 20 m2 room. The M500 power amplifier shares the same topology for owners planning a larger set of electronics from the brand.

Alternatives

The Circle Labs A200 is the brand's other integrated amplifier listed alongside the AS100.