Pi filter

[Eccu]

I decide add "pi filter" to my Cresendo amplifier power supply.
So I have question about those coils.
How big (mH) should those coils be?
And how many coils must be added?
How thick copper wire must be?

I have six 10000yF capacitors (three per rail).
Supply voltage is +-50VDC.

 

[NickC]

try with values of 2mh-15mh. Wire size depends on how much of amps you normally running it. go big amps current capability allows upgrading and safer. For further and more detail on the calculations check the forum. There was a huge section on how to design a pi-filter. Very informative. They provide the calculation on the db reduction that you want to achevied. If you are too lazy to search then just go with a 2mh(one of the pass amp uses this with 10000uf -2mh -10000uf ). For you try 10000uf -2mh-20000uf so that way there would be bigger reservoir in case of change in current. On the current / wire size i not to sure. This pi filter is for A operation or AB?

 

[UrSv]

Crescende would be AB so I would not recommend an LCL filter for the PSU. I would try CRC if anything. The dynamic current draw from the PSU might cause more problems than the gain. I would try an CRC...

/UrSv

 

[Eccu]

Crescende would be AB so I would not recommend an LCL filter for the PSU. I would try CRC if anything. The dynamic current draw from the PSU might cause more problems than the gain. I would try an CRC...

/UrSv

How big this R must be?
And how many watts (W) it´s must be?

 

[wuffwaff]

Hello Eccu,


I´ll also use a pi filter for my crescendo. 15mF-1.8mH-50mF. The choke is 1.4mm and 0,38 Ohm. It will reduce the ripple voltage by quite a lot from 300mV to 15mV at 1A bias. With a big secondary capacitor I don´t think there will be a disadvantage in dynamic situations.
You need 4 chokes for a double mono power supply.

william

 

[jarthel]

where can I get an instructions on how to make a pi filter? Thanks

jayel

 

[HarryHaller]

Pie filler

Blueberry or apple? Oh, I'm sorry, you said pi FILTER. Nevermind.

 

[HarryHaller]

pi filter

Actual power supply pi filter

 

[AudioFreak]

you may even find that a CRC filter causes hassles..... because of the wild variance in current draw of Class AB designs they are generally not suited to CLC filters. CRC should be less problematic but still not without it's problems. Use 10000uF + R1 + 20,000uF---> output

 

[Eccu]

Thanks everybody!!! Positive feedback gives good effect.


Because I have only one transformer with four outlets, so is this good schema for my Cresendo amplifier?

If I use this schema, where I shall add those chokes or resistors?

Something about this schema:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=2633



:

 

[Ren Hoek]

Pie?

One piece for me, please. one from the middle, with no crust.

Ren