Pass Laboratories just launched the X.8 (aka Point.8) Amplifier Series, which consists of five Class A amplifiers and four Class AB amplifiers, four two-channel and five monoblock models. The two-channel amps include the X150.8, the X250.8, the X350.8 and the XA30.8. The mono models include the X600.8, the XA60.8, the XA100.8, the XA160.8 and the XA200.8. Their per-channel power ratings range from 30 for the two-channel XA30.8 to 600 for the single-channel X600.8.
Based on the design of the Pass Labs’ X.5 Series amplifiers from 2006, the output stages of the larger Point.8 Series have been designed to bias more deeply into the Class-A operating region. They feature large push-pull Class-A operating envelopes for low distortion and good loudspeaker control at ordinary listening levels.
Pass Labs claims it successfully increased the amplifiers’ Class-A operation by employing higher power Toshiba MOSFETs (metal-oxide semiconductor field-effect transistors) than in its earlier amps. The X250.8 and XA100.8 amplifiers each use 56, while the X350.8, X600.8, XA160.8 and XA200.8 models each use 72. The power supplies are also larger than those of earlier amplifiers. The X150.8, X250.8, XA30.8, XA60.8, XA100.8, X350.8 and X600.8 models have a third more storage capacitance as well as new CRC (capacitor-resistor-capacitor) filtering to round out the edges of the supply ripple.
The smaller Point.8 models — the X150.8, the X250.8, the XA30.8, the XA60.8 and the XA100.8 — also feature new and larger heat sinks, an upgrade that lowers distortion and dissipates the energy of the larger bias currents.