Circle Labs P300

The P300 preamplifier is a fully balanced design from input to output.The design of the P300 was guided by the idea of building a preamplifier as neutral as possible for the signal with the shortest possible signal path. Internal wiring was kept to a minimum. The preamplifier was built using the latest JFET and BTJ transistors in the proprietary Circle Amp topology. A resistor ladder controlled by a remote control is responsible for volume control.

Circle Labs P300 Preamplifier is a fully balanced design from input to output. It features two XLR and three RCA line inputs. The preamplifier is built using the latest JFET and BTJ transistors in Circle Amp's proprietary topology. The main intention was to contour a preamplifier with the shortest possible signal path with a minimum number of stages and minimal internal wiring. Volume control is realized by a relay-controlled resistor ladder. The 63-step resolution control is equipped with an aluminum remote control. An ultra-low-noise power supply based on independent transformers for both channels with LL cores and Elma silmic ll capacitors was developed especially for this design. The power supply has two cascaded stabilization stages. This largely separates the sensitive audio path from mains interference. These stabilizers use an LED matrix as a reference voltage source, featuring many times lower noise than the Zener Diodes or IC stabilizers traditionally used in these places. The housing is milled from 5754 aluminum on digital CNC machine tools.