Help calculating RC values for rectifier snubber

[Eric]

I've completed my a40 amp, and now have a nice little humming sound coming through my speakers - I've been thinking about this and concluded it would me much nicer to hear the music rather than "hhhhhmmmmmmm....".

I'm fairly certain I do not have a ground loop, so my next area to look at involves putting a snubbing circut in my bridges. I've found lots of references to calculating optimum snubbers here, and have reading through it.

My problem, however, is that I can't seem to add correctly - perhaps someone can help me out here: On the bottom of page 9 there are two formulas, one for Rs and the other for Cs. Trouble is, using the numbers in the articles, I cannot even duplicate the values in the example🙁


For example, the article calculates Rs by taking the square root of (0.113mH/600pF) and gets a value of 471 ohms. When I take the root of (0.113mH/600pF), I get 0.01488!

I know I'm missing something stupid, like units conversion or something... Any help?

Thanks!
Eric

 

[stappvargen]

Units...

You are right on the money. It's a unit thing.
0.133mH is 0.000133 H (or 0.113 milliHenry), NOT
0.113 microHenry (in this case at least!). People seem to use m for micro sometimes as
well which adds to the confusion.

😉

/Niclas

 

[Eric]

Thanks, Niclas! Now my numbers are working!🙂