The twin chassis XP-27 eclipses the already exceptional performance of the well-reviewed and well-received XP-15, XP-25 & XP-17: delivering enhanced RIAA performance at a fraction of the previous distortion. The new design uses double shielded low noise toroidal transformers in external supply connected via aviation grade circular connectors using silver over oxygen free copper. The power supply is dual mono with two transformers with lower radiated and mechanical noise. Noise is the most prominent part of THD+N at low levels, so by lowering noise we get better resolution and dynamics.The XP-27 input and gain circuitry are similar to that found in the Xs Phono. This means switching and loading is done at higher signal levels, minimizing noise and improving low level performance.
More info - https://www.passlabs.com/preamplifier/xp-27