Pass Labs X250.5 power amp (Demo)

by **centrecircleaudio** Tue Nov 03, 2009 4:42 pm

Pass Labs X250.5 Power Amp (Demo Unit)

Pass Labs continues to improve its power amplifiers. After five years, these acquired enough mass to warrant a change in designation, and the X.5 series was announced. The improvements are:
Cascode JFET Symmetric front end – input differential MOSFETs have been replaced by the same JFETs we use for the input devices on our MM and MC phono stages. They have very much less noise, higher input impedance, and greater linearity. They operate self-biased in a symmetric quad topology, each device cascoded and level shifted to form the full voltage gain stage of the amplifier.
More power output devices – Greater quantities of matched complementary power Mosfets operated as followers, giving more current and power handling, and also improved linearity.
Single-ended Class A bias – The output stage not only uses a heavy bias current for push-pull Class A operation to a large portion of the rated power, but also has a single-ended bias source for single-ended Class A at low wattage.
New bias circuit – A newly developed bias generator has eliminated three sources of variation in bias current in the output stage. It also allows approximately 20% greater power output for a given supply voltage.
Improved power supplies – The power supplies have been given greater storage capacitance, larger / quieter power transformers, fast recovery rectifiers (twice as many), and improved harmonic filtering in both the primary and secondary supply circuits.
Better layout – All portions of the amplifier circuitry have been refined with respect to wiring and circuit board layout so as to achieve lower noise and distortion and greater reliability and serviceability.

RM 18,500

Please Contact : CENTRE CIRCLE AUDIO TEL: 03 77282686