| Bassterror |
Hi
What kind of PSU whould u suggest for five 3886 clones?
I don't want to use 5 little transformers. I prefer a single one with about 400-500VA (enough:confused: )
I want to adopt this disign here, because I can save the PCB:
http://dogbreath.de/Chipamps/GainCa...inCardCopy.html
I don't want to use a snubber PSU with big caps, just the suggested 2200µF. (Bad idea?)
Main question is:
whould it be a serious disadvantage to use a single big rectifier for all 5 Channels? I think something like that:http://www.schuro.de/Daten/Fairchild/RHRP1560.pdf |
|
|
| Bazukaz |
Hi,
There is no need to have a separate transformers for each channel.
For 5 channels , 500W trafo is about the lowest value you should go(i would use approx 600W).
Filter caps should be 5,000 - 10,000 uF for best results , so total capacitance of about 25,000 - 50,000 uF is needed per rail.
For rectifier , you don't need ultrafast diodes , they are designed for high frequency circuits.A standard powerful bridge rectifier(40A or so) should be better here.
Regards,
Lukas. |
|
|
| Bassterror |
| quote: | | Filter caps should be 5,000 - 10,000 uF for best results , so total capacitance of about 25,000 - 50,000 uF is needed per rail. |
Isn't that too much?
I've read that many people use smaller caps, like the 2200µF in the link i posted, because more would affect the reproduction of higher frequencies? Or Do u mean with a snubber?
I liked the Idea of using only 2200µF per IC, those big caps for five channels are quite expensive...
What do u think about the that circuit in the link? |
|
|
| Bazukaz |
Hi,
Larger caps will provide better ripple filtering.
I think the main reason why lower value caps are used is usually cost.A small(0,1uF) ceramic cap must be placed near IC pins to improve high frequency filtering.
Regards,
Lukas. |
|
|
| cjd |
| quote: | Originally posted by Bassterror
Isn't that too much?
I've read that many people use smaller caps, like the 2200µF in the link i posted, because more would affect the reproduction of higher frequencies? Or Do u mean with a snubber?
I liked the Idea of using only 2200µF per IC, those big caps for five channels are quite expensive...
What do u think about the that circuit in the link? |
You're not off base. Cost is not the only reason folks don't use more capacitance. It can negatively change the midrange and up. Topologies/theories to "fix" this abound - I have not tried most to be able to comment (am working with regulated circuits right now).
However, if you're not regulatingm 100VA/ch is generally an absolute minimum. 150VA/ch (and these days more) is preferred. Without the big caps, the trafo has to have that surge capacity.
At any rate, one bridge is fine. Though some think the rectifier/diodes used can also change the sound. . . ;)
C |
|
|
|
