There is a “germanium sound”. It is especially suitable for guitar amplification, and can apply to harp and some keyboards. The sound of germanium has a warmth and a granulity as pleasant to the ear as the tube sound, without being the same : The sensation of warmth is about equivalent (for analog reasons, in particular the Miller effect that dynamically attenuates the high frequencies). The sonic grain of germanium is generally a bit rougher than the tube grain, and especially less flat and plain than silicon …
In all domains of audio, germanium transistors and their “good defects” are opposed to the cold pharmaceutical perfection of integrated circuits.
After years spent in tests and development, I feel able to specify some characteristic parameters… And happy to share this knowledge that I apply in the products shown on this site ; stuffs just to please the guitars.