How about comparing the role of tran-sconductance in screen voltage regulation in a simple series resistor or wire to a diode, ( and zener) in series? Because the 2 are completely different, therefore the trans-conductance action result for screen dissipation is not exact the same.
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Screen dissipation arises from the product of screen voltage and screen current. Transconductance has nothing to do with this.Koonw said:
To get low distortion amplification, the screen either has to be fixed in voltage with respect to the cathode (pentode mode) or fixed with respect to the anode (triode mode). A smallish resistor is acceptable, and brings other benefits.
A diode either does nothing if it remains forward biased, or disconnects the screen if it ever becomes reverse biased. It is just possible that a forward biased diode could have enough dynamic impedance to act as a screen stopper and so prevent parasitic oscillation, but a resistor or lossy choke will probably do a better job.
The screen voltage on G2 determined the transconductance, if you have a different Vg2 be it 100v, 150v, 200v or 250v..transconductance would be all different. You also need the correct Eg2 datasheet.
Vg2 is never identical, if component or value that is used to derive the Vg2 are different, they need to become stabilised.. taking all into account, what if one results in Vg2 250v, the other just 150v, how does this come about?
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No. LDRs have quite long decay and relatively fast attack. And even in SE peaks are almost symmetric, however it depends on the sound material. With PP it is ideal.
Page 34, fugure 2.
http://denethor.wlu.ca/pc300/optoisolators/analogoptoisolatorintroduction.pdf
Even if it adds some negligible distortions of bass, they are much less nasty sounding that would sound clipping.
Here is the demo, on 0:55
https://www.facebook.com/Wavebourn/videos/1365809046810726/
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It is a parallel reality; no matter what we discuss here, they have own theories.
Action speaks louder than word.
I have about 20 units of guitar amp for proof, where are yours?!
To prove that series diodes are useless?
When they are always open, with low dynamic resistance in respect to the load, and 0.7V drop that is nothing compared to the voltage they supply, you can remove them and listen for yourself.
People with experience (and sales) often believe that experience (and sales) somehow automatically either replaces or enhances understanding. It can't do the former, and sadly it does not always do the latter.Koonw said:
A diode will either conduct or not conduct. In this position (screen feed) it will either do nothing or do harm, except for the small possibility of damping parasitic oscillation.
Someone somewhere sometime came up with this daft idea, probably based on some misunderstanding of how valves work, and others now propagate it.
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