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GregH2 26th August 2010 03:23 AM

PS Caps
 
Hi All,

Due to transformer options I have decided to go for a full dual mono power supply with my Aleph 3 project (two individual 300VA transformers). The aleph 3 requires about 100 000 uF per channel. I am going this route as I can use cheap off the shelf toroids this way.

As I am going for a dual rectifier design, and will therefore have a total of 4 bridge rectifiers, things are going to get complicated and messy if I use p2p wiring and big discreet capacitors.

I am contemplating making a power supply PCB with the rectifiers on the board, and using many 3900uF panasonic FC caps in parallel, also mounted on the PCB. I will have the PCB specially made using extra thick laminate and lots of mounting holes to try and reduce vibration and microphonics.

Can anyone see any problems or disadvantages with this approach over using big discreet capacitors, as per the norm?

Also, when using two toroidal transformers, is it ok to mount them on top of eachother using a single bolt down the middle and a rubber gasket in between?

Your advice is appreciated!

Greg.

Zen Mod 26th August 2010 06:55 AM

Quote:

Originally Posted by swordfishy (Post 2283995)
Hi All,



Can anyone see any problems or disadvantages with this approach over using big discreet capacitors, as per the norm?

nope .



Quote:

Originally Posted by swordfishy (Post 2283995)
Hi All,

Also, when using two toroidal transformers, is it ok to mount them on top of eachother using a single bolt down the middle and a rubber gasket in between?


yes .

GregH2 26th August 2010 01:16 PM

Thanks. After all this I found some cheapish 100k uF caps that I have decided to use so my initial post is now obsolete. They can be seen here:

Digi-Key - 495-4219-ND (Manufacturer - B41456B7100M)

Hope they're adequate!

GregH2 26th August 2010 02:15 PM

Hmm,

I ordered the above 100 000uF caps thinking the ESR was quite low (4.1 milliohms), but now I see the ESL is perhaps quite high (20nH). Actually I don't know what is regarded as good... but I see they offer a 12nH low inductance version that may have been better...dammit!

This is one expensive learning curve...

Zen Mod 26th August 2010 02:28 PM

EPCOS - use them and switch the brain off ;

besides that - when you're using insane amount of capacity - put 50uF motor run caps as bypass , and enjoy . so - one motor run for positive , one for negative PSU leg

GregH2 26th August 2010 02:33 PM

Great thanks.

Everything is ordered. Looking forward to getting it together!

Interesting the use of motor run caps. Never heard of that before but I guess it's a neat way to get high capacitance film capacitors....interesting.

And yes, I do think too much and I also never sleep... :)

Zen Mod 26th August 2010 03:05 PM

Quote:

Originally Posted by swordfishy (Post 2284341)
......

Interesting the use of motor run caps. Never heard of that before but I guess it's a neat way to get high capacitance film capacitors....interesting.

.....

that's old story

cheap and pretty much best solution to have pro quality film caps .

not just a few audiophool caps are rebranded and sometimes re-cased industrial caps


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