Building Quiet Audio Power Amplifiers Requires Best Wiring and Layout Practices
There is a misconception that noise pickup is reduced by placing the input RCA connectors (and similarly XLR input connectors in a fully balanced system) on opposite sides of the amplifier rear panel and then running short wires to the amplifier modules. This arrangement is the worst of all worlds. The internal loop areas available […]
Hifisonix ‘Symphony’ Line Preamplifier
I designed and built this preamplifier while living in Taiwan a few years ago. The Symphony preamp features Baxandall tone controls, up to 7 inputs, a class A 2 W headphone amplifier and a Goldpoint 24 position attenuator. The write-up describes the design process and choices in some detail and my listening impressions: Part 1 […]
Ovation e-Amp: A 180 Watt Class AB VFA Featuring Ultra Low Distortion
The e-Amp is a 180 Watt RMS (very conservatively rated into 8 Ω ) fully balanced symmetrical (‘FBS’) amplifier featuring an emitter follower triple (EFT) bipolar output stage and beta enhanced VAS stage. The amplifier can be configured using jumpers for TMC (Transitional Miller Compensation) or straight Miller compensation (MC). The VAS can be lightly […]
Ovation 250 Power Amplifier
The Ovation 250: A 250W per Channel Audio Power Amplifer (updated 1st June 2013) This amplifier was built in 2005/2006 and this write-up originally published in 2009. Introduction Diy Audio is a wonderful activity:- if you cannot afford a $10 000 power amp, you can always build one that comes pretty damn close in terms of sonics […]
12 point checklist for anyone using opamps in an audio design
Opamp User Guide V1.0.pdf
X-Altra Mini One Line Preamplifier
The X-Altra Mini One is a simple line preamplifer based on the National Semiconductor LM4562 (also known as the LME49720) that I built around 2008 and which served me well until about 2014 when it was replaced with newer more sophisticated designs. Nevertheless, this simple preamp sounded very good, and thanks to the LM4562 (which […]