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rhythmsandy 8th August 2012 08:42 AM

Choosing the right capacitors for C12? necessity of it with power psu
Hi Im trying to use Mundorf AG capacitors with the circuit

PA100 DIY 2x LM3886 in parallel gainclone audio amplifier

the capacitor C12 and C14 also come under the power supply capacitors.

Im driving the 5.1 amplifier for pc purpose with 10 inch subwoofer from peerless SLS series with 70watts RMS input with two LM3886 in parallel 8 ohms and others with be small 2 way with 3 inch midbass and 1 inch vifa ring tweeter.

Now im thinking of using elna silmic 2 for the C12 and C14 capacitors but chipamp uses only 100uf for this and shine7 uses 1000uf and since its elna its expensive when it comes to the 1000uf.

I am thinking that using one 1000uf and one 10000uf for the supply capacitor for all the channels. Is that ok? or do i need to use 100uf for each channel or 1000uf for each channel?

Please give me a suggestion on this one...

Nuuk 8th August 2012 09:13 AM

Use 1000uF as in the diagram (most designs use 1000uF). There is no 'best' brand of capacitor in this position but many prefer Panasonic FC.

Presumably you are using the PSU that goes with this design so stick to the 10K/100uF.

rhythmsandy 8th August 2012 10:34 AM

I want to use Mundorf 10000uf + 1000uf Elna Silmic2 and do i require to use the capacitors at C12 and C14?

AndrewT 8th August 2012 12:15 PM

C12 & 14 are the local decoupling.
Location relative to the chipamp power pins is possibly more important than what make/type of capacitor is selected.
Similarly for C11 & 13, except that location is even more important.

rhythmsandy 8th August 2012 06:05 PM

what is the disadvantage of using one decoupling capacitor for all the channels does it makes any difference...

1. chipamp website states to use 100uf for this ( which is a cheaper solution but how does it sound different? ) I would be using a 3 inch midbass + 1 ring radiator for the satellites.

2. If Im using a common decoupling capacitor does it has any sonic variations.. Im expecting 100uf is good in mids and 1000uf will add more bass to it? what could be the result?

AndrewT 8th August 2012 10:56 PM

Read up on decoupling. You are completely misunderstanding the purpose of these capacitors.

rhythmsandy 9th August 2012 07:08 AM

I got it. It works like a buffer to get the chip isolated from its main power source. So I think higher the better and not too high. I think i can fix it as 220uf at this stage and a .1uf in parallel with this capacitor preferably wima. Am I right here?....

rhythmsandy 9th August 2012 07:09 AM

I think it has to be just in contact to the pins of the chip..

rhythmsandy 9th August 2012 07:25 AM

here is one link about how decoupling caps work would be helpful for the people who need some info on it.. Demonstrating the Effect of Decoupling Capacitors - YouTube

So i think its best to use mixed versions of the caps like..

100uf elna silmic2
.1uf wima
100pf Tantalum

to clear off the interfered waves...

thank you very much Andrew..:)

rhythmsandy 9th August 2012 11:06 AM

For Power supply capacitors Im thinking of using Mundorf AG. Is there any better alternative to that? Ive heard that using Mundorf AG capacitors will improve the sound quality by 80% so thinking to use this one.... rest of the decoupling and signal caps would be using Silmic2 and the input cap could be Mundorf or CTR capacitor for 1uf as DC blocking capacitor.

Please suggest me if I can improve beyond this. Resistors wise I cant go with CADDOCK since it will be way to expensive overall and also experts say it sounds pretty cynical and some dont even notice that... The change is not as much as how the capacitors make the change. ...

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