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In the Forum: Analog Playback
In the Thread: The last phonocorrector: “End of Life" Phonostage
Post Subject: Ring-ringPosted by N-set on: 2/9/2012
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 Romy the Cat wrote:
N-set, can you explain what you are saying? What kind ringing are you implying? Are you taking about mechanical ringing of the wire or about the after pulse ringing?


I referr to the after pulse ringing. The parasitic tank formed by input
choke inductance + its parasitic capacitance+transformer leakage+parasitic cap of the transformer winding
gets excited at diode switching (the current momentarily falls so the big inductance of the choke produces a
voltage glitch,trying to maintain the current flow; this glitch excites the mentioned tank).
I observed in my PSU HT choke ringing at some 30kHz, which penetrated the closeby filament supply (the first cell).
Moreover I have an improvised, very simple laptop "scope" with a floating ground, so I could also see the current
waveform in the input choke circuit. You can see it in the post #172, red trace. Perhaps I'll try to bleed the supply heavier
and see if it damps the heavy oscillations.
Cheers,
N-set

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