PassLabs-Aleph1 pwramp.pdf | | Aleph 1 Service Manual - Rev. 1.0, 1.1
PRODUCT DESCRIPTION The ALEPH 1 is a high performance Mosfet single-ended Class A audio power amplifier, intended for maximum performance in reproduction of music. It is a simple design, having only three gain stages: input differential pair, cascaded voltage gain stage, and output followers. All three gain stages are biased by current sources from the negative supply. The output stage will operate as a single ended system at lower power levels and will operate as a push-pull system at levels above the bias point of the constant current source. There are only marginal differences between the Rev 1.0 and 1.1. SIMPLIFIED SCHEMATIC To best understand the operation of the amplifier, refer to the simplified schematic Figure 1. The front end of the amplifier accepts a balanced or unbalanced input signal at two N channel Mosfets operating as a differential pair. They are provided with bias by a current source from the negative rail which operates at a c |