Fully-balanced design

By employing a fully-balanced circuit design from the input section to the output stage, the AP-505 keeps the audio signal as unadulterated as possible as it moves through the amplifier, the result being extremely low distortion levels and an excellent signal-to-noise ratio (assisted by the effective elimination of common-mode noise).

Carefully selected components, exclusively designed for hi-fi applications

At the input stage, where sound quality is fundamentally defined, high-quality MUSES8820E dual op-amps are employed for both the XLR and RCA inputs. In the power supply section for the input stage, both the left and right channel rectifying circuits are completely independent of the power transformer onwards and employ four, high-capacity, 4700μF capacitors on each channel (8 in total), achieving clear soundstage separation between channels.
At the XLR input section, a well-designed circuit delivers excellent signal integrity, thanks in part to the elimination of coupling capacitors that can often lose audio information as a signal travels through them.

An oversized toroidal power transformer

In the power supply, the AP-505 employs a high-capacity toroidal-core transformer, with Schottky barrier diodes in the rectifying circuit. Unlike conventional diodes, Schottky barrier diodes reduce rectifier noise, leading to a ‘cleaner’ supply and a more stable delivery of current.

Passive-cooling design for silent operation

It makes no sense to design an amplifier that delivers excellent sound to a pair of speakers but which itself generates distracting operating noise from a cooling fan. From the outset, our engineers were determined to use a circuit and layout that would allow sufficient natural cooling, one that would allow the creation of a compact but powerful amplifier that didn’t need the help of a cooling fan.