[gareth magennis]

On Monday, 1 March 2021 at 14:29:10 UTC, Don Pearce wrote:
On Mon, 1 Mar 2021 06:01:58 -0800 (PST), gareth magennis
wrote:

On Monday, 1 March 2021 at 10:12:40 UTC, Don Pearce wrote:
On Mon, 1 Mar 2021 20:58:52 +1300, geoff
wrote:

On 1/03/2021 8:43 pm, Don Pearce wrote:
On Mon, 1 Mar 2021 12:48:16 +1300, geoff
wrote:

On 1/03/2021 8:55 am, Don Pearce wrote:
On Sat, 27 Feb 2021 04:31:33 -0800 (PST), "


Since you won't get off your lazy arse and do the work, I've done it
for you. Of course I knew precisely what the result would be before I
started, but it was a boring Sunday evening so here goes.

https://youtu.be/-hQgI0eCO08

d



I think a spectrum analyser display would have been more relevant.

geoff

No it would not. The screen I showed illustrated perfectly that there
was no selective harmonic boosting going on. That would have resulted
in a beat walking through the ring. A rock-solid, edge-induced ring is
what I intended to show, and that is exactly what I did show. Now, how
about addressing the result?

d


I would be curious to see the oredrs of harmonics and if they altered
over freq.

geoff
I've taken an FFT showing all the harmonics up to and beyond the
ringing frequency. The harmonic at the ringing frequency is marked.
Make of it what you will.

http://www.soundthoughts.co.uk/look/ringing.gif

The ring itself is of very short duration so despite its amplitude, it
contains very little energy compared to the harmonics which are
continuous. That is why it won't show up in the frequency domain
(unless the Q is so high that it continues at considerable amplitude
all the way to the next excitation). To see such a low energy signal
you have to choose the appropriate domain, the one in which it can be
isolated. That of course is time. I'm really disappointed that I have
to go though these hoops - they should not be necessary for a
technical audience.
d



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These are screenshots of the Pultec clone ringing:
https://imgur.com/Ou0BGml

and with 100 Ohms in series with 0.01uF:
https://imgur.com/jaLv5Dz

Did you get those backwards? The one with the 100 ohms is much worse.
That first one though - pretty much identical to my tests. The FFT
would look identical for sure. I think I nailed it.

d

No I didn't get them backwards, I just assumed that the much larger initial overshoot would be more likely to cause the 90Hz issue than the longer ringing.

Don't know what that was based upon really, other than a guess.