The P300 preamplifier is a fully balanced design.
The creation of the P300 was inspired by the idea of a preamplifier that is truly neutral with the shortest possible signal path. Inner cabling was strictly limited.
The preamplifier was designed around the newest JFET and BJT transistor types and uses a proprietary Circle Amp topology.

Volume is controlled by a resistor ladder and a remote is supplied.

Circle Labs P300 The P300 preamplifier is a fully balanced design. The creation of the P300 was inspired by the idea of a preamplifier that is truly neutral with the shortest possible signal path. Inner cabling was strictly limited. It was designed around the newest JFET and BJT transistor types and uses a proprietary Circle Amp topology. Volume is controlled by a relay operated resistor ladder and offers 63 step resolution. An aluminum remote is supplied. We designed a specially built, low noise power supply based on two independent channel transformers with LL cores and Elma SILMIC II capacitors. The power supply has two cascading steps of stabilisation. The stabilisers use an LED matrix as a source of reference current, characterised by remarkably lower noise than traditional merged Zener diodes. The frieze-finished aluminium 5754 casing is crafted using digital CNC machines.