UCD400 Power Supply mod?

ghisdal · 16th June 2007, 12:30 PM

Hi,

I am going to build 2 monoblocks using UCD400AD modules. I have ordered 2 pcs of the Hypex standard power supply.

I have 6 10000uF 80V Elna caps I wish to use. Is it hard to do this? Can I just add them in series to the print along with the others?

Please advise, I suck at electronics, but pretty handy with a soldering iron...

mazurek · 16th June 2007, 01:24 PM

Placing the capacitors before the psu module doesn't make sense. Placing them after the psu will be overriding the fusing and the dc blocking shut off relay. At the very least, you would need to fuse again after the additional capacitor bank. You could also build your own psu, just copy the simple rectifier/cap arrangement shown in the UCD docs, of course then it won't have any dc protection.

ghisdal · 16th June 2007, 02:12 PM

I mean if it is possible to take off the 2 normal caps in the psu and replace them with the three Elna's that i've got to increase the totalt amount of uF's?

If so, how would I connect them?

mazurek · 16th June 2007, 03:12 PM

You could do that by desoldering the existing capacitors, and soldering in 16 gage wire where the terminals were. You would connect all the caps in parallel for each rail. You might also be able to find an electrically common place and drill it out to put in something like a faston.

Whether you should is another question that other people may be better qualified to answer....

Your other caps / layout may affect noise performance, current inrush, etc.

Maybe before you could setup the system sucessfully using the existing psu, verify that DC offset is not a problem in your setup. Then build your own psu on a breadboard with a rectifier bridge/schotky diodes and your elna caps, and some 1/4" fast-ons. In fact, you can visually inspect the hypex psu and copy their rectifier bypassed by small ceramic caps arrangement.

dmfraser · 19th June 2007, 07:15 PM

Just remember that you cannot add capacitors off on a branch and expect a worthwhile effect.

The power has to come from the source, go to the capacitors and then to the load. That is the source and load both connect to the capacitor terminals directly.

Both on the + and - capacitor leads..

If the capacitors are on a branch, you have the resistance of the wires effectively in series with the capacitors, reducing their effect quite a bit.

16th June 2007, 12:30 PM	#1
ghisdal diyAudio Member Join Date: Nov 2006	UCD400 Power Supply mod? Hi, I am going to build 2 monoblocks using UCD400AD modules. I have ordered 2 pcs of the Hypex standard power supply. I have 6 10000uF 80V Elna caps I wish to use. Is it hard to do this? Can I just add them in series to the print along with the others? Please advise, I suck at electronics, but pretty handy with a soldering iron...

19th June 2007, 07:15 PM	#5
dmfraser diyAudio Member Join Date: Dec 2003 Location: Orange County, CA	Capacitor wiring Just remember that you cannot add capacitors off on a branch and expect a worthwhile effect. The power has to come from the source, go to the capacitors and then to the load. That is the source and load both connect to the capacitor terminals directly. Both on the + and - capacitor leads.. If the capacitors are on a branch, you have the resistance of the wires effectively in series with the capacitors, reducing their effect quite a bit. __________________ Dan Fraser

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16th June 2007, 01:24 PM	#2
mazurek diyAudio Member Join Date: Aug 2005	Placing the capacitors before the psu module doesn't make sense. Placing them after the psu will be overriding the fusing and the dc blocking shut off relay. At the very least, you would need to fuse again after the additional capacitor bank. You could also build your own psu, just copy the simple rectifier/cap arrangement shown in the UCD docs, of course then it won't have any dc protection.

16th June 2007, 02:12 PM	#3
ghisdal diyAudio Member Join Date: Nov 2006	I mean if it is possible to take off the 2 normal caps in the psu and replace them with the three Elna's that i've got to increase the totalt amount of uF's? If so, how would I connect them?

16th June 2007, 03:12 PM	#4
mazurek diyAudio Member Join Date: Aug 2005	You could do that by desoldering the existing capacitors, and soldering in 16 gage wire where the terminals were. You would connect all the caps in parallel for each rail. You might also be able to find an electrically common place and drill it out to put in something like a faston. Whether you should is another question that other people may be better qualified to answer.... Your other caps / layout may affect noise performance, current inrush, etc. Maybe before you could setup the system sucessfully using the existing psu, verify that DC offset is not a problem in your setup. Then build your own psu on a breadboard with a rectifier bridge/schotky diodes and your elna caps, and some 1/4" fast-ons. In fact, you can visually inspect the hypex psu and copy their rectifier bypassed by small ceramic caps arrangement.

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