UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Craig Sawyers · 19th Mar 2020, 11:30 am

Hi Andy

The first and third attachments are two designs we were discussing initially. Apparently Bateman's oscillator is nicked from a guy called Scott Wurcer's design (on DiyAudio low distortion oscillator thread)

I'd forgotten entirely about JLH's design, that seems (at least if his measurements are right) good to -140dB distortion (0.1ppm, or 0.00001%). It is very difficult to measure because the sine wave generator has to have a distortion comparable to or less than the distortion analyzer - so say -150dB

That actually exceeds the best and latest edition of the Audio Precision gear. With a few transistors and a (now long obsolete) R54 thermistor.

19th Mar 2020, 11:30 am	#12
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,992	Re: Low distortion oscillator Hi Andy The first and third attachments are two designs we were discussing initially. Apparently Bateman's oscillator is nicked from a guy called Scott Wurcer's design (on DiyAudio low distortion oscillator thread) I'd forgotten entirely about JLH's design, that seems (at least if his measurements are right) good to -140dB distortion (0.1ppm, or 0.00001%). It is very difficult to measure because the sine wave generator has to have a distortion comparable to or less than the distortion analyzer - so say -150dB That actually exceeds the best and latest edition of the Audio Precision gear. With a few transistors and a (now long obsolete) R54 thermistor.