Pass Labs - X260.5

Overview

Pass Labs - X260.5

Class AB Amplifiers from 150 Watts to 1000 Watts

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Cascode JFET Symmetric front end – input differential MOSFETs have been replaced by the same JFETs we use for the input devices on our MM and MC phono stages.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.

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.

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.

About the Brand

Based in Foresthill, California, USA, Pass Labs was founded by Mr. Nelson Pass, a well known figure in the high end audio community.

Although Pass Labs has only been around for a decade, they have collected more awards than many companies who have been around a lot longer.

Mr. Pass is known for unique and innovative, as well as practical, circuit designs. Pass' first designs, in the Aleph line, were single-ended pure Class A solid state. The current Pass Labs "X" series amplifiers use a distortion canceling balanced audio signal circuit, and continue to receive critical acclaim. Today Pass Labs makes amplifiers, preamplifier and speakers.

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