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Bypassing big electrolytic de-coupling caps

Is the practice of bypassing big electrolytic caps (de-couplers) a waste of time, or does it have a legitimate benefit? I recently read a post on another board (and I quote) that bypassing big electrolytic caps with small film caps are as useful as “tits on a bull”.

I have 30 (yes thirty) big electrolytic caps in my phono stage. I am thinking of bypassing them all with small(ish) film caps.

Also I am wondering that if bypassing big electrolytics is beneficial, would using inexpensive polypropylenes give close to the same benefit as more expensive film caps?

Lastly, can somebody recommend an inexpensive and physically small cap. I would like to place the bypass under the circuit board to retail a neat appearance. There is about a ¼ inch gap between the circuit board and the bottom plate.

Thanks
Paul
pauly

Showing 1 response by pauly

pauly OP
1,012 posts
 
+++ Their [electrolytics] ability to hold a large charge is much more important than their sound quality. +++

Rwwear, firstly, thanks for the response but I have to strongly disagree with that statement. Ability to hold charge is largely irrelevant.

De-coupling (power supply) caps have to be able to charge/discharge quickly and do so in very linear/smooth fashion. Electrolytic caps cannot do that – they are slow and charge/discharge in very non linear and spiky way. Electrolytic are the very worst caps, be it for coupling or de-coupling applications.

I have replaced electrolytic power supply caps in a few applications with motor run caps that are about 1000 times faster, and each time I have had a tremendous improvement in sound. Detail, impact, dynamics, smoothness, naturalness, you name it, is improved.

The issue I am facing now is I have very little room so I cannot make use of motor run caps (or film caps for that matter). I am wondering how much impact a couple of 1.0uF film caps will have on 7800uF worth of electrolytics.

Thanks
Paul
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