On Fri, 26 Feb 2021 02:29:37 -0600, gray_wolf
wrote:
On 25/02/2021 7:01 pm, Scott Dorsey wrote:
gareth magennis wrote:
The Gearslutz post says 100 Ohms in series with 25pf, which I thought made a lot more sense.
I'm reluctant to accept that without comfirmation from the company, though, which I still haven't received.
Is that a typo? should it be 22pF, or even 22nF? I struggled to find a 25pF cap.
Hence my reluctance.
Put a 1 KHz square wave through. Does it look nice and square at the output or
does it ring?
Mild ringing: http://www.panix.com/~kludge/xformers/DSC00263.JPG
Catastrophic ringing: http://www.panix.com/~kludge/xformers/DSC00258.JPG
If you add a 600 ohm termination resistor (which everybody should be using
running a Pultec into a modern output anyway) does it get better or worse?
If the square wave looks good, things are good.
You can use the calibration output from a Tek scope as a 1kc square wave
generator. It's convenient and comes free with the scope.
--scott
Any idea what the catastrophic ringing harmonics would look like on a spectrum
analyzer.
The same is non-catastrophic but bigger. That is just a judgement
call. The way you judge it to be actual ringing is that one harmonic
is much bigger than any other. That is the ringing frequency.
d
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