Special Design Features

Nº433 Power Amplifier

Massive Power Supply

Balanced Design

Thank you for purchasing the Nº433 Power Amplifier. While this amplifier is straightforward in everyday use, it includes several design features that are responsible for its outstanding performance. In particular, this amplifier defies the accepted wisdom that it is impossible to design a large, powerful amplifier that also has all the finesse of the finest smaller amplifiers. A few of the technical highlights that make this possible are described below.

The Nº433 features three large, robust power supplies. Each supply includes a high-capacity, low-noise toroidal transformer, and two large, low ESR (“Equivalent Series Resistance”) capacitors.

Heavy oxygen-free copper bus bars enhance the efficiency of power distribution within the amplifier and eliminate variances intro- duced by the wiring harnesses that are commonly found in lesser- performance amplifiers. High-frequency power supply bypass is accomplished on individual PC boards by components of several film types. The resulting uniformly low power supply impedance seen by the various circuits within the amplifier lays the foundation for the massive power delivery and extraordinary finesse that characterizes Mark Levinson amplifiers.

A truly balanced input topology eliminates the need for an input buffer amplification stage, allowing the first stage differential amplifier to be driven directly by the source. Matched impedances are presented to the source. Both signals travel through identical circuit paths.

Meticulous attention to the layout of the amplifier, including careful mirror-imaging of circuits to cancel magnetic fields, minimizes magnetic field distortions that can occur with a massive power delivery system. A balanced input signal remains balanced throughout the voltage gain stages. Rejection of common mode noise and distortion is achieved in the final, current gain stage.