Why use bypass caps with electrolytic filter caps

[Mike Sweeney]

I've seen this done.. I sorta knew why but this video explains it really well. I also know there are opinions that differ as to do it or not. I think since my 2245 is still apart on the bench ( been restoring some cassette decks lately).. I might play around and see if I can hear/see a difference. I'm putting it here because I have not seen this discussion in the other Forums I hang out in.

I am curious since most of the conversation was around switching supplies and given that the old Marantzs use a transformer, I wonder how much really applies.

From the description
Electrolytic capacitors are common, but knowledge of their limitations is uncommon. A demonstration is shown highlighting the difference in performance between electrolytic and ceramic capacitors in power supplies

 

[marcthisdate]

Thank you for this Mike, really informative video.

 

[mbz]

In the past, I have used bypass caps on main filters and audio path caps though not noted any positive effect.
I've become sceptical of by passing main filters which handle rectified AC, ie, 100-120Hz. As pointed out, the
bypass only kicks in at very high (MHz) frequencies, so unless there is some RF induced or the by product
of rectification the bypass will do nothing. 2 cents worth?

 

[Mike Sweeney]

As pointed out, the
bypass only kicks in at very high (MHz) frequencies, so unless there is some RF induced or the by product
of rectification the bypass will do nothing

That was my take away also for the same reason. It doesn't do any harm, but I don't think it does any good either. And caps are cheap

 

[Ray Gianelli]

@Mike Sweeney, thanks for posting this. It filled in more than a few gaps in my knowledge!

This graph from the video says it all:

 

[steveo1960]

Thanks Mike. Very good video.

 

[airtime]

Thank you I actually learned a little more about capacitor selection. Honestly I've read on caps but it always seems to be a mystery to me. Seeing a video does help. I guess I'm getting older and stupider.