what size capacitors to use?

[mgriff]

hi I have two 200 watt amps. I'm in the process of building a power supply for those amps. I allready have the toroidal transformer and the bridge rectifier. the amps need 50V+ and 50V- at about 3 amps max. the question is what size filter caps do I need. Any help would be appreciated!

 

[FastEddy]

here is a start point

http://aussieamplifiers.com/other_prod.htm

Note the pictures and specs for these filter / bridge / capacitor boards ... These are generally used for pairs of ~400 to ~800 watt Class D amps, but the basics all work for just about any DC filtering concept.

(I got two of the above PSU-One units for two 400 watt class d amps ... so I would have "split" supplies and plenty of filtration = overkill, probably.)

 

[Dick West]

have you checked this person's web site. It has an excellent article on PS design, caps needed, etc.

http://www.sound.westhost.com/site-map.htm

 

[mgriff]

thank you very much for the quick reply!

 

[AndrewT]

Hi,
try 2mF to 3mF per Apk of output current.

eg. 200W into 8ohms is 56Vpk into 8r giving a peak current of 7Apk. My recommendation is use at least 2mF/Apk giving +-14mF (14,000uF) per channel. Doing the same numbers for a 4ohm load (@56Vpk) requires >+-28mF/channel

 

[richie00boy]

I would use a bridge+cap combo per amplifier to get better performance. I'm sure you will find 10000uF per rail fine for what I presume to be your 8 ohm load based on the current figure quoted. If you want to make it better double up on the caps, but try it before first and see what you think.

 

[AndrewT]

Hi Richie,
thanks for corroborating the per channel requirement. It is worthwhile.