Not polarized (Bipolar) electrolytic capacitor in power supply
Oct 24, 2008 at 11:18 AM Thread Starter Post #1 of 6


New Head-Fier
Feb 26, 2008
Hello, I have just read some web articles that say that non-polarized (or better bipolar) electrolytic capacitor show much less distortion than polarized one (by Cyril Bateman)
So, why don't put them in power supply??
Well I make the try
I put in power supply two polar back to back (+--+) capacitor
Terrific!! The sound improved dramatically !!!
This depends hugely also on the capacitor brand.
Capacitors run cold, so I think I didn't make mistakes...
But I never seen in the web a circuit with not polarized elecrolytic in power supply.
Since they are in DC I suppose one is working as a diode the other at normal polarity, but I'm not sure about this...
Please tell me what you think...
Oct 24, 2008 at 6:09 PM Post #2 of 6
most bipolar electrolytic cap data sheets specify that the electrical orientation (dont know how to describe it better) of the cap be changed periodically.

I dont know if this applies to back-to-back polar caps as well, but its probably worth further research.
Oct 25, 2008 at 5:19 AM Post #3 of 6
I hope you've realised that you just cut the effective capacitance of the capacitors in half when you put them in series like that, with 2 470uF's the circuit only sees 235uF.

You got any links to real data (measurements) that show that bipolar have less distortion than polar electrolytic?

And capacitors don't behave anything like diodes, ever. Have a read of this to see how caps in series behave
Oct 25, 2008 at 8:36 PM Post #4 of 6
Thank you for the reply!

>You got any links to real data (measurements) that show that bipolar have less distortion than polar electrolytic?

Unfortunately I cannot do measurement for such stuff but...

Here the ref:




4) my blind test!
L3000.gif audio test with short cicuiting all the second antiserie capacitors with a switch to obtain a normal polarized capacitors of 470uF (against the best in class 235uF back to back) on each rails
Nov 1, 2008 at 8:38 AM Post #6 of 6
New (necessary) improvement: capacitor shunt diodes to prevent reverse polarisation.

Yeah I miss them: to connect back to back capacitor without diodes is wrong and dangerous (in DC I measured 4 volt of reverse voltage in my amplifier...!!!)
I had a suspicious until I read this article which confirmed me:NonPolar
So I put the diodes...and the sound changed... (i don't tell you how....i don't want to bother you furtherly)

Shunt diodes schema
Now the measured reverse DC component is now half 1 volt...

Users who are viewing this thread