Meeting Report: August 2015 Hugh Dean on Practical Amplifier Design

Designing Practical High End Audio Amplifiers

On Monday August 10th 14 members and visitors gathered at the SAE Institute in South Melbourne to hear Hugh Dean speak on the topic “Designing Practical High End Audio Amplifiers”

Section Vice-Chair Graeme Huon introduces Hugh Dean
Section Vice-Chair Graeme Huon introduces Hugh Dean. Photo – Rod Staples.

Hugh presented a potted history of his efforts with his audiophile-grade Aksa designs, giving us an insight into some of his design techniques, and tradeoffs between stability and audio quality.

He raised an intriguing proposition that the vanishingly small distortion figures of typical solid-state amplifiers are unnecessary; rather the key to a good sounding amplifier is the appropriate mix of distortion products (the “distortion profile”). Hugh claims that, by virtue of the carefully chosen distortion profile, his solid-state amplifiers can sound as good as the best valve amplifiers.

He displayed circuit diagrams showing the evolution of his Aksa amplifier design, with descriptions of key circuit elements.

The presentation concluded with a demonstration of one of his amplifiers playing back a range of music, followed by a spirited Q&A session.

Committee member Julian Driscoll and Hugh discuss his presentation

The audio recording can be played or downloaded here
Hugh’s paper, including circuit diagrams can be viewed here

Thanks to Graham Haynes and his trusty Tascam for the audio recording.
Special thanks to the SAE Institute for providing the venue for our meetings.