ucd 700 power supply caps.

back · 19th May 2008, 06:55 PM

hi have order a pair of ucd 700.

the datasheet says 10000uf per rail but it seems too small capacitance to me.

there is an example at the site that uses 264.000uf per channel or 132.000uf per rail.

again i think that`s too much.

i am going to use 1kva per chanel.

what capacitance do you recomend?

i already have 8x10000uf/100v nippon chemicon caps(for both channels).

you think they are enough,i should buy more of the same or and use them in parallel or forget about them and buy something like

47.000uf/100v?

TheMG · 19th May 2008, 10:49 PM

IMO that would be way overkill.

First of all, you don't need a 1kVA transformer per channel, as the amplifier will never actually draw this much, not even close. Keep in mind that the RMS power rating is obtained using a pure tone (sine wave). Music however is quite different, even bass-heavy music at near-clipping levels will not yield close to the RMS power rating. That being said, you should be fine with about 600-700VA per channel even for very heavy use.

About the capacitance, well, there seems to be mixed opinions about that. Experiment with different amounts, you may find out you only need a lot less than what you planned to get the sound you want.

back · 20th May 2008, 06:32 AM

thanks for your answer.

i know they are too big but since i have them i will use them.

about the capacitance i will again use 4x10000uf per channel

and if i need i will buy some more but from your message i guess

it is going to be rock solid with that.

TheMG · 20th May 2008, 07:21 PM

Just one thing though, if you plan to use the Hypex Softstart, that it may not like the very high capacitance (resistors going up in smoke and stuff).

As this guy found out: http://www.nodecorporation.co.uk/hyp0020.htm (might of had something to do with the size of the xfmr too though).

back · 20th May 2008, 09:42 PM

i have read this.

no i designed my own soft start.

thx.

19th May 2008, 06:55 PM	#1
back diyAudio Member Join Date: Nov 2005 Location: crete	ucd 700 power supply caps. hi have order a pair of ucd 700. the datasheet says 10000uf per rail but it seems too small capacitance to me. there is an example at the site that uses 264.000uf per channel or 132.000uf per rail. again i think that`s too much. i am going to use 1kva per chanel. what capacitance do you recomend? i already have 8x10000uf/100v nippon chemicon caps(for both channels). you think they are enough,i should buy more of the same or and use them in parallel or forget about them and buy something like 47.000uf/100v?

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19th May 2008, 10:49 PM	#2
TheMG diyAudio Member Join Date: Jan 2008	IMO that would be way overkill. First of all, you don't need a 1kVA transformer per channel, as the amplifier will never actually draw this much, not even close. Keep in mind that the RMS power rating is obtained using a pure tone (sine wave). Music however is quite different, even bass-heavy music at near-clipping levels will not yield close to the RMS power rating. That being said, you should be fine with about 600-700VA per channel even for very heavy use. About the capacitance, well, there seems to be mixed opinions about that. Experiment with different amounts, you may find out you only need a lot less than what you planned to get the sound you want.

20th May 2008, 06:32 AM	#3
back diyAudio Member Join Date: Nov 2005 Location: crete	thanks for your answer. i know they are too big but since i have them i will use them. about the capacitance i will again use 4x10000uf per channel and if i need i will buy some more but from your message i guess it is going to be rock solid with that.

20th May 2008, 07:21 PM	#4
TheMG diyAudio Member Join Date: Jan 2008	Just one thing though, if you plan to use the Hypex Softstart, that it may not like the very high capacitance (resistors going up in smoke and stuff). As this guy found out: http://www.nodecorporation.co.uk/hyp0020.htm (might of had something to do with the size of the xfmr too though).

20th May 2008, 09:42 PM	#5
back diyAudio Member Join Date: Nov 2005 Location: crete	i have read this. no i designed my own soft start. thx.

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