Pass Labs

The first product, the Aleph 0, shipped in 1992. It was a monoblock design rated at 70 watts into 8 ohms and was unique in using three gain stages of power MOSFETs, including a push-pull output stage biassed by a big constant current source. The amplifier operated as a single-ended Class A up to its 70-watt rating and in push-pull Class A at higher wattages.

At this time, Nelson hired his next-door neighbour, Elena Tong, to help produce the amplifiers, and she has managed much of the company to this day. A stereo version called the Aleph 0s followed, along with a preamp called the Aleph P. A larger version of the Aleph 0 called the Aleph 1 shipped the following year and was a monoblock rated at 150 watts.