Headphone amplifier

I have always been a music fan and inspired by many performers. I have been a fan of audio equipment and have tried to understand what makes this type of equipment tick. The various aspects of processing audio from one source to the speaker can be considered by some people a form of alchemy, which it is not. There are very sound basis for why the sound quality is altered by cable structure and size and the choice of components used in an audio circuit. However you don’t need to spend hundreds of pounds on interconnects, £20 if you know what you are doing.


I have long been inspired by writers over the years on this subject and have studied many publications on this subject, and for my tastes I prefer the sound produced by a class A audio amplifier.


Having made one class AB headphone amplifier to compliment a Crimson pre-amp twenty three years ago, here I have decided to make a class A headphone amplifier to compliment my Linsley-Hood power amplifier.


This design is a Class A single ended headphone amplifier for my own amusement and I have produced this as an article for publication. Details will appear here in due course.


Latest update…..


The headphone amplifier is now complete, the article is now complete and is now in the hands of EPE. They have accepted the article for publication and will be in print in due course. The article was a little late getting to the magazine  as Easter intervened. But I have to admit I am very pleased with the overall unit(s). The amplifier has been tested with a number of Sennheiser and Beyer headphones of 37 to 270Ω. It works amazingly well, the amp is very quiet, no noise, and distortion is at a very acceptable level. Frequency response is flat from 10Hz to over 60KHz.


My thanks to the editorial staff of the UK magazine at EPE for publishing the article in the November 2009 edition.


With the new headphones bought for Christmas, the sound is superb. Beyer DT770 Pro 250 www.dolphinmusic.com.




Gain: 10dB (measured)

S/N: >90dB (100dB measured)

Dynamic range: >90dB (100dB measured)

THD+N: 0.035% (max), 0.01% typical at 1KHz

Max output: 7v rms into 270(distortion 0.01%).

Frequency response: 20Hz to 12KHz (-0.1dB), 10Hz to 18KHz (-0.3dB), -3.0dB at 90KHz. (measured).