Poland-based manufacturer Circle Labs has launched a new integrated amplifier called the AS100. The AS100 is a transistor amplifier designed, according to its designers, for sonic accuracy and control. Instead of a wide range of features, the focus is said to be on signal purity, neutrality, and power stability.
The AS100’s volume control operates via a precision 63-step resistor ladder with 0.1% tolerance resistors, controlled by high-quality signal relays. Compared to conventional potentiometers, this principle reportedly results in significantly improved channel balance, long-term stability, and reproducibility. The Circle Labs AS100 is built entirely in dual-mono mode. Each channel has its own toroidal transformer.
In the input stage, the Circle Labs AS100 uses low-noise Burr-Brown J-FET transistors to achieve high signal purity. The output stage, on the other hand, uses bipolar transistors to provide the necessary current supply and dynamic range. The entire amplifier circuit is based on Circle Labs’ proprietary Circle Power technology, which combines the properties of symmetrical and asymmetrical designs.
The power supply design is also focused on control and stability. A total filter capacitance of 200,000 µF ensures ample power reserves and low distortion, even with dynamically demanding music or complex loudspeaker loads. The frequency response is wide: from 3 Hz to 500 kHz (-3 dB), and the damping factor is over 250 at eight ohms. The AS100’s output power is specified at 65 watts (RMS) at eight ohms. With a speaker impedance of four ohms, this translates to 110 watts per channel.
