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Old 7th January 2011, 10:38 AM   #11
DF96 is offline DF96  England
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I very much doubt that electron mobility is a significant factor at low frequencies (audio) and low power (headphones). This sounds like just another attempt to start a fashion for mild effects boxes masquerading as preamps. If you put "digital sound" in and get "analogue sound" out then it has fiddled with the signal and is therefore an effects box. Will "germanium sound" now replace "tube sound" ?
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Old 4th June 2015, 05:18 PM   #12
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Default Germanium Transistors

There is an audible sound difference between germanium and silicone transistors (it appears that all together germanium devices have lower intermodulation distortion and this is giving "clean" sound similar to tube pre-amps). The best possible transistors for that purpose were AC151r and they were used in professional equipment (for example "Uher 4400 Report Stereo" tape recorder, non-IC version). They were also used in mixing consoles/phono pre-amps from late sixties/early seventies (by "Grundig","Telefunken" etc.). They have been replaced by silicone BC549c NPN/BC559c PNP. For example, AKG is using these silicone transistors in their built-in mike-preamps for the model 1000S. The orientation in this design is about 50uA (micro-amps) collector current and 10:1 max. ratio between collector and emitter resistor with no shunting capacitor (feedback) for the lowest noise levels.
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Old 6th June 2015, 09:15 AM   #13
DF96 is offline DF96  England
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There is a very good reason why early solid-state equipment used germanium transistors. There is an equally good reason why later equipment used silicon (not "silicone" - that is floor polish or car wax!). In each case they were using the best devices currently available.

Almost all SS equipment is designed with lots of negative feedback so the end result does not depend on the characteristics of the devices - which on their own are very nonlinear. About the only exception is where signals are so small that BJT exponential distortion is small enough to be ignored.
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