Germanium diodes with bias.

[catman]

G'day all, a circuit observation more than anything. Most will know of my passion for Hi Fi AM and low distortion AM detectors. Running diodes with applied and preferably adjustable bias is a good approach, however I normally use schottky diodes like the 1N5711 and I love their very clean sound when bias is used.

Last night though I tried a experiment with using bias with conventional gernmanium diodes (I used an old GEX34 germanium diode), and the results were interesting.

Germanium diodes almost don't require bias due to their inherently excellent 'sensitivity', but the addition of bias (when correct bias is applied), reduces overall audio distortion and the germanium diodes have a nice 'rounded' sound which is quite pleasant to the ears.

Interestingly enough, even when full bias is applied germanium diodes react a little differently to schottkys. Germaniums produce a more graceful sounding 'thump' as detection stops, whilst schottkys produce a more nasty sounding 'clunk,' if that makes any sense.

Overall, I think that I prefer the softer/easier/more rounded sound of germanium diodes with applied bias. Any comments or thoughts? Regards, Felix (vk4fuq) aka catman.