Zeus 75 Power Amplifier

A Zero Feedback Class A (AB) Power Amplifier

"The perfect amplifier is wire with gain"

Pair of Zeus 75 Monoblock Amplifiers and Power Supplies (2007)

Amplifier Highlights

  • Zero feedback.
  • Balanced and isolated input and outputs.
  • Output configurable to drive any impedance load, from electrostatics to sub-ohm parallel linear array loudspeakers
  • Good EMI/RFI performance.
  • Low voltage operation ( sub 60 volts ), no potentially lethal HT.
  • Only two power semiconductors required for Push Pull version.
  • Minimum components, little opportunity for noise generation (150 dB signal to noise ratio).
  • No capacitors in the audio signal path.
  • "Direct" signal connection from input to output.

Zeus General Amplifier Schematic

Zeus 75 Distortion versus Power Output.

Use with 4 ohm impedance speakers with 2:1 step down output is not normally recommended but this graph is to demonstrate the amplifier operation where distortion level plateaus at 1% (unlike conventional amplifiers where it would continue to rise).

Power at maximum output is over 100 watts.

Note: Full Class A or Class AB operation depends on output transformer configuration, mosfet bias level and load being driven.


Building a Zeus 75 - Information on Construction

Input Transformer Specification

Output Transformer Specification - 75W

MOSFET Matching with L200 Current Source

FFT Test Result with 2SK1529 Audio FETs

Zeus System - Pre + Power

Full end to end configuration with TX-102 TVC input.

Email: susan@audiophonics.com

All design and other information, drawings and images on this website are
Copyright 1992-2010 Susan Parker MIET (unless otherwise credited).

These designs and other information may be used to construct systems specifically for personal NON commercial use only.

N.B. Personal liability disclaimer applies - see T&C.