Hegglun Ian

Hegglun Ian

Ian Hegglun was born in New Zealand and has enjoyed designing audio power amps as a hobby since buying a Sinclair Z30 module and modifying it. After an interlude at a university to gain an electrical engineering degree he resumed designing amplifier and speaker systems including motional feedback, negative resistance damping and current drive. A fascination with linear mode CMOS inverters lead to the discovery of their square-law basis and then use in unusual power amp designs. CMOS inverters were used in an Electronics World Class-AB amplifier in 1995. More recent designs use curved type Class-A.


Ian also has an interest in homopolar motors for electric cars and gained his Masters in this area. He has worked as a registered power engineer and taught electronics in New Zealand, and worked in manufacturing in Australia. Ian took 6 years off work recently to set up a private electronic library and to be with his Dad during his last few years. He hopes to set up a website to share his many ideas. He is now living in Austalia.

Written articles
Towards a reconciliation of measurements with listening tests

Standard THD measurements give a clear indication of amplifier linearity for the signals with which it is measured. Curiously, however, very often THD performance does not seem to correlate with...

Current driven Output-stage class AB power amplifier

This article covers a simple modification that overcomes most of the tricky thermal stability issues of regular Class-AB output stages. It uses a common emitter power output stage to remove the...

Square-Law class-A: a family of efficient class-A power amplifiers

It is well known that Class-A gives the best sound quality in audio power amplifiers but the efficiency is so low that it is impractical to build much more than around 20 watts per channel. The...

A cube-law power amplifier - Class A at 1/4 of the dissipation

A Cube-law audio power amplifier – class-A at ¼ the idle dissipation           Vol 8

Ian Hegglun

Ian’s article in...