To me grounded grid amplifier is like this:
But I have been noticing that also this "good old" name has today other meaning.
I am wondering why. Did'nt the inventor of "new grounded grid amplifier" know that this name was already in use ?
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But I have been noticing that also this "good old" name has today other meaning.
I am wondering why. Did'nt the inventor of "new grounded grid amplifier" know that this name was already in use ?
To me grounded grid amplifier is like this:
But I have been noticing that also this "good old" name has today other meaning.
I am wondering why. Did'nt the inventor of "new grounded grid amplifier" know that this name was already in use ?
I resist the new imho incorrect usage vehemently, and agree with you and DF96, imho the originator of the misuse of this term did it for reasons of self promotion.
Not sure why someone would want to apply positive as opposed to negative feedback unless one also wanted to boost the OLG or wanted to make an oscillator of course..
The funny thing is, most of the 'new grounded grid' circuits don't even ground the second grid but use it as a negative feedback point! Maybe they should call it 'ungrounded grid'? I still prefer STP as a name, but 'cathode-coupled amp' seems to be what the textbooks call it.
Putting positive feedback around a (real) grounded grid stage could increase the input impedance for the tube below it (cascode driving case), which could be quite useful for a triode driver's linearity. But one will more likely end up with a VHF oscillator unless extreme counter-measures are taken. (ferrite beads, ground plane for grid 1, plate cap for the grounded grid stage, cage, feedthru cap in ground plane)
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Yes. I'm curious: what is your application? Except for oscillators and bootstraps, positive feedback is usually avoided.
Used it before for negative impedance PSU's, but never in audio.
I'm also curious!
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