Power amplifiers mono — Pass Labs XS150

The XS150 is a mono power amplifier from Pass Labs, the company founded by designer Nelson Pass that builds class A and low-feedback amplifiers. It is a pure class A design and belongs to the Xs series of mono amplifiers, where the Xs 300 sits above it.

Key specs that matter

Rated output is 150 W into 8 ohms in pure class A, and gain is 26 dB. The amplifier weighs 102 kg, a high figure relative to its rated output.

Engineering and use context

As a class A amplifier it runs continuously hot regardless of the music being played, so the room needs adequate ventilation.

Pairing

With this class A design, the sensitivity of the speakers and the size of the room count for more than the wattage number.

Alternatives

In the lower-priced XA series, Pass Labs offers the XA160.8 as another class A monoblock.