[Milsurplus] Germanium to silicon

[Bob Camp]

Hi

The R-392 is probably at the head of the list of "most converted  
radio" when it comes to putting solid state devices into tube  
sockets. I have seen a number of these radios. Solid state conversion  
does result in more audio output power, other than that the  
performance of the radio does not improve at all with solid state.  
Considering that the 392 is far from an optimum tube design that's  
really saying something.

Bob


On Aug 30, 2007, at 9:42 PM, Frank wrote:

> Ray Fantini wrote:
>> Beware! lots of old germanium circuits relied on leakage
>> for bias. I have replaced germanium with modern
>> transistors in dividers and primitive logic gates and
>> they sometimes work but cannot imagine what would happen
>> in small signal circuits. although the internet is full
>> of articles on how you can replace all the tubes in a
>> radio with a couple fets and get equal performance so I
>> am told anything is possible. Ray Fantini KA3EKH
>
> I did not know that there was such a difference between germanium  
> and silicon based devices. I knew there was a difference and that  
> silicon won out, but I had no idea that the additional leakage of  
> old germanium devices became a design criteria. A bad design criteria.
>
> My personal view of folk trying to 'solid state' a good tube design  
> is that they are nuts.  No, there is no way to replace all the  
> tubes with fets and get equal performance. Anyone trying is out of  
> their mind.
>
> Accept the tube circuits for what they are and do.  If you want a  
> solid state version, then design one from scratch. Don't mess up a  
> good vacuum tube design with solid state devices.
>
> As for stuff you find on the internet, yes, beware.  I find stuff  
> that is an obvious spoof.  I can recognize it as comedy, someone  
> less knowlegable might think it is real.
>
> Even the stuff that is not purposely spoofed may not deliver the  
> goods.  Articles that are long on theory and short on results are  
> suspect.  If the proof is left up to the student, then it is pretty  
> certain that the author either has his tongue in his cheek or his  
> head up his ass.
>
> Regards,
> Frank Kamp
>
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