Quote:
Originally Posted by Max
hmmm... no.
The tube is stable cause if you have a regulated current flowing in the filament you have also a very stable temperature inside... no matter of temperature outside of tube, cause there's vacuum inside or some inert very low pressure gas (e.g. argon).
Now, if you have also a stable plate potential you have a perfect amplifier for the purposes you want... very stable.
In semiconductors/bipolar the minority carriers are a huge (if not enormous) pain when also 0.1°C variation is at transistor body... when rest of circuit has very hi amplification.
If you use instead multiple tubes, with voltage gain e.g. 20 you can have enormous gain and very strict thermal induced variations... that's why e.g. old tube based BFOs are SO COOL! 
But seem you didn't follow me... oscillator stability is important or not in LRLs ??? 
Kind regards,
Max |
Of course, is important, always!