Усилители мощности моно — Pass Labs XA 160.8

The XA160.8 is a monoblock amplifier working in pure Class A, made by Pass Laboratories, part of the Point.8 generation that covers nine models across the XA and X ranges. In the XA line it sits between the XA100.8 and the larger XA200.8, and one monoblock per channel is required, so a stereo system uses a pair.

Key specs that matter

Rated output is 160 W into 8 ohm per chassis, all of it in Class A. The gain figure is 26 dB, and an input of 1.79 V is enough for full output. Bandwidth runs from 1.5 Hz to 100 kHz. Input impedance is 50 kohm on the single-ended input and 100 kohm on the balanced one, and the damping factor is quoted at 200. At idle each unit draws 600 W from the wall, which is the price of keeping the output stage fully biased with no signal present. The chassis measures 483 x 546 x 279 mm (width, depth, height).

Engineering and use context

Its output section is built from 72 matched power MOSFETs per channel, a device count that spreads current and heat across a large array. Across the Point.8 range, Pass enlarged the power supplies over the previous generation, adding about a third more storage capacitance and a new CRC filter of capacitor, resistor and capacitor. The front end, which holds the input and voltage gain stages, was redesigned so that each of the nine models has its own version matched to its output stage, differing in size, voltage, bias current, dissipation and the split between single-ended and push-pull bias. Balanced XLR connection is provided for signal transfer with noise rejection. The front panel carries a large meter with blue illumination that indicates how much current the amplifier is steadily drawing, not signal level. Because Class A bias runs at full value all the time, the unit stays hot with or without a signal, so it needs clear air on all sides and a mains supply able to carry two such loads continuously. Pass covers the amplifier with a warranty of three years.

Pairing

A high input impedance presents little burden to tube or solid-state preamplifiers, and the moderate full-power sensitivity means most line-level sources and preamps can drive it to its limit. The damping factor suits multi-way speakers with demanding bass sections, while the power rating points to speakers of moderate to high efficiency for large rooms.

Alternatives

The Pass Labs XA200.8 is the larger mono Class A model in the Point.8 family, with 200 W into 8 ohm in a deeper chassis.