Quote:
Originally Posted by Clondike Clad
Why not use a mosfet and not a tube???????????????????
Now I KNOW TUBES IN SIDE AND OUT
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Welll... I must say that in some applications tubes are fairly better still today.
The problem is that semiconductors technology never really solved that issue of stability...
As an example... I made many years ago an oscillator for MD using common fets... I made everything absolutely by the book... considered controlling the current and making feedbacks , but , at the end, I tested the oscillator under various conditions and found that was absolutely instable vs temperature, no matter compensation strategies I tested (many).
I've then redesigned using small tubes , 6.3V powered and got perfect , stable sinus , no matter if I also swing an hairdryer near the osc module...
The MD was rock steady, then I learnt that for some stuff... better using old tubes than newer stuff.
About stability, experience say me that mosfets are good... but tubes are BETTER.
Kind regards,
Max