Noise in Electronic Circuits
I’ve gathered a few articles here on noise as a go-to reference for anyone interested in the subject. These articles really focus on Johnson noise and not induced noise which is discussed in depth in the ‘Ground Loops’ post elsewhere…

Technical Requirements of Phono Preamplifiers by Tomlinson Holman
The two articles below were written in the 1970’s, nearly a decade before the arrival of the CD and the ‘perfect sound forever’ claim made by Philips. There was a lot of focus on phono amplifier performance at the time…
Richard Lee’s Ultra-Low Noise MC Head Amp
This design was a development of Marshall Leach’s MC head-amp from the 1970’s and to my knowledge, Richard Lee’s implementation presented here has not been bested in terms of noise – about 280pV/rt Hz in a well implemented exemplar. Importantly,…
Class A Buffering the Correct Way
Here’s a simple way to force an opamp output stage to run in class A when used with a discrete buffer output stage – it takes just 1 resistor to provide a near constant current source load. Operating the opamp…
The ‘Feedback is Bad’ Fallacy
This is one of the most depressing articles I’ve read in a long time about ‘feedback being bad’; it is filled with inaccuracies and for most part plain wrong at every level. Aimed at people who are not technically literate…