Re: Adding capacitance to PS / How much if any?

209.48.140.10

Posted by Mark Kaepplein on May 31, 2000 at 17:05:23

In Reply to: Adding capacitance to PS / How much if any? posted by daryl on May 23, 2000 at 07:55:25:

I added lots of capacitance with Panasonic FA (replaced by FC in their line) in a Marantz CD63SE. These caps have very low resistance up to frequencies much higher than most electrolyics ~300khz - even in the largest sizes! OSCON's resistance goes up after 20khz, and they are small. I used the largest values that would fit, especially in local bypass locations at load devices. The stock Cerafine electrolyics had about 5 times higher ESR.

Regulators do very well at low (under 1 khz) frequencies, but their impedence rises above that. Circuit trace inductance starts to play a big part at higher frequencies and longer distances from the main resoviour. Hence, local bypass electrolytics are what count. What you want is low ESR. Capacitance smoothes ripple, but that's not a problem in regulated supplies. It just so happens that ESR decreases with capacitance (below the resonant frequency) in good capacitors, and up to a point. That's really the only reason more capacitance is good. In unregulated supplies, extra capacitance will also help the bass.

If my Toshiba derived Magnavox DVD is like your your Toshiba, I doubt you will gain much for your efforts. The only electrolytic on mine that looked worthy of replacement was on the board with the jacks and filtered the +5v to the audio DAC.

Diode upgrades, RF shunt capacitors and ferrite on the supply are probably worth the effort. If nothing else, it will cut down on the noise going back on the AC line and into the rest of your gear.

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Follow Ups Full Thread

Topic - Adding capacitance to PS / How much if any? - daryl 07:55:25 05/23/00 (15)

Re: Adding capacitance to PS / How much if any? - Mark Kaepplein 17:05:23 05/31/00 (1)

Thanks you.... - daryl 08:56:17 06/01/00 (0)

Re: Adding capacitance to PS / How much if any? - mneedes 16:11:46 05/29/00 (4)

Re: Adding capacitance to PS / How much if any? - daryl 17:27:12 05/29/00 (2)

Re: Adding capacitance to PS / How much if any? - mneedes 12:57:00 06/04/00 (1)

Great info -- thanks so much, Matt (nt) - daryl 07:54:23 06/05/00 (0)

Also, use linear regulators to further improve output impedance - mneedes 16:17:17 05/29/00 (0)

Re: Adding capacitance to PS / How much if any? - rcrump 08:08:28 05/24/00 (5)

Good info. How bout a little more ???? - Sean 08:25:31 05/24/00 (0)

Harris Hyperfast vs. Hexfred - daryl 08:24:46 05/24/00 (3)

Re: Harris Hyperfast vs. Hexfred - rcrump 23:09:13 05/24/00 (2)

Will let you know -- thanks for the info (NT) - daryl 08:24:51 05/25/00 (1)

Re: Will let you know -- thanks for the info (NT) - rcrump 17:23:16 05/25/00 (0)

Re: Adding capacitance to PS / How much if any? - bobwire 08:19:07 05/23/00 (1)

Re: Adding capacitance to PS / How much if any? - daryl 08:32:46 05/23/00 (0)

Follow Ups

Re: Adding capacitance to PS / How much if any? - Mark Kaepplein 17:05:23 05/31/00 (1)

Thanks you.... - daryl 08:56:17 06/01/00 (0)

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