Introduction
The Aleph P is a single ended Class A audio preamplifier, the first produced by Pass
Laboratories. It combines completely new design thought applied to a traditional topology
and the experience of twenty five years of amplifier design. This manual applies to the
second version of the Aleph P, which incorporated circuit improvements and remote control
operation.
This preamplifier flows from a commitment to create the best sounding product: a simple
circuit with the most natural characteristic. The Aleph P integrates power Mosfet devices
and single ended Class A operation in a simple topology in order to deliver the most natural
sound possible.
The circuitry of the Aleph P breaks new ground in simplicity and performance. Each gain
stage consists of a single Mosfet power transistor operated “common source” mode. One
such circuit amplifies each signal polarity of a balanced input signal, and their operation is
inter-coupled to allow optimal operation with both balanced and unbalanced input signals
while still providing balanced and unbalanced outputs. It retains the important simple single-
ended characteristic while operating either single-ended or balanced.
It is unique in providing superior flexibility and performance with balanced and unbalanced
inputs and outputs, converting one to the other as desired without switches or adapters.
The Aleph P absolutely minimizes the number of components in the signal path, and yet
retains exemplary objective performance specifications. More importantly, it pushes the
edge of the art in exploring how much subjective quality is obtainable with a new but very
elementary gain stage.
A very few people are involved in the production of this product. I supervise all phases of
the construction, and I test and listen to each preamplifier myself. If you have questions,
comments, or problems, please feel free to contact me directly.
Thank you for purchasing this preamplifier. It is my sincere hope that you will enjoy its sound
as much as I do.
_________________________________
Nelson Pass
Serial #
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Date:
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