desing +/- 70v 5A power supply

fity · 5th January 2006, 02:43 PM

first excuse me for my english.
I need a desing of +/- 70v 5A power supply for a power amplifier.
I have a toroidal transformer 50+50v . may be help me? filtred and if posible regulated.
thanks

edl · 5th January 2006, 03:21 PM

Hi,

regulated won't works, the sec voltage of the trafo is too low, you may need 2*60-70V for that. Anyway regulated voltage is not needed to feed an amp in most cases.

So you need a 25A graetz-bridge, and two 10000uF/80V cap. That's all.

fity · 9th January 2006, 12:35 PM

is better to put 4 x 4700uf 80v caps? or more.

Eva · 9th January 2006, 01:39 PM

Using more capacitance reduces voltage ripple. On the other hand, using more capacitors of a smaller value (yielding the same total capacitance) may sometimes improve performance if the combination produces less ESR and ESL (equivalent series resistance and inductance) or features a higher total ripple current rating in comparison with a single capacitor.

fity · 10th January 2006, 06:25 AM

is this a good desing of power supply for power amp?
is too big the capacitance of caps than the only 10000uf ?
anything changes in this desing?
i need help

eem2am · 14th April 2012, 12:13 PM

if it is a Class D amplifier then i believe that you need a very very solid power rail supplying it....so you will need a power supply that can give you +/-70V with no more than say 300mV maximum undershoot or overshoot after a no-load to full-load transient and full-load to no-load transient.

sawreyrw · 14th April 2012, 09:35 PM

fity, a 500 VA transformer is too low a power, if you intend to operate the supply with a continuous load of 5 amps. Further, the RMS currents in the transformers secondaries will be far greater than 5 amps RMS.

eem2am · 15th April 2012, 04:14 PM

if its class d then theres no way itll be drawing 5A continuously.

However, as mentioned class d needs well regulated rails with little over/undershoot, so you will need more than what your trafo can give, as the other contributors said.

.....see my simulation of a class d amplifier in the class d forum to see how the class d draws power..posted today

RJM1 · 15th April 2012, 06:34 PM

You do know this is a 6 year old thread.

oiphy · 15th April 2012, 06:36 PM

hehe..... made my day lol

5th January 2006, 02:43 PM	#1
fity diyAudio Member Join Date: Feb 2005 Location: vivo en españa concretamente en la provincia de jaen	desing +/- 70v 5A power supply first excuse me for my english. I need a desing of +/- 70v 5A power supply for a power amplifier. I have a toroidal transformer 50+50v . may be help me? filtred and if posible regulated. thanks

15th April 2012, 06:36 PM	#10
oiphy diy newbie diyAudio Member Join Date: Sep 2011 Location: norway	hehe..... made my day lol __________________ " If you're going throu hell, keep going"

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5th January 2006, 03:21 PM	#2
edl diyAudio Member Join Date: Oct 2004	Hi, regulated won't works, the sec voltage of the trafo is too low, you may need 2*60-70V for that. Anyway regulated voltage is not needed to feed an amp in most cases. So you need a 25A graetz-bridge, and two 10000uF/80V cap. That's all.

9th January 2006, 12:35 PM	#3
fity diyAudio Member Join Date: Feb 2005 Location: vivo en españa concretamente en la provincia de jaen	is better to put 4 x 4700uf 80v caps? or more.

9th January 2006, 01:39 PM	#4
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	Using more capacitance reduces voltage ripple. On the other hand, using more capacitors of a smaller value (yielding the same total capacitance) may sometimes improve performance if the combination produces less ESR and ESL (equivalent series resistance and inductance) or features a higher total ripple current rating in comparison with a single capacitor.

14th April 2012, 12:13 PM	#6
eem2am Banned Join Date: Jun 2011	if it is a Class D amplifier then i believe that you need a very very solid power rail supplying it....so you will need a power supply that can give you +/-70V with no more than say 300mV maximum undershoot or overshoot after a no-load to full-load transient and full-load to no-load transient.

14th April 2012, 09:35 PM	#7
sawreyrw diyAudio Member Join Date: Apr 2006 Location: Minnesota	fity, a 500 VA transformer is too low a power, if you intend to operate the supply with a continuous load of 5 amps. Further, the RMS currents in the transformers secondaries will be far greater than 5 amps RMS.

15th April 2012, 04:14 PM	#8
eem2am Banned Join Date: Jun 2011	if its class d then theres no way itll be drawing 5A continuously. However, as mentioned class d needs well regulated rails with little over/undershoot, so you will need more than what your trafo can give, as the other contributors said. .....see my simulation of a class d amplifier in the class d forum to see how the class d draws power..posted today

15th April 2012, 06:34 PM	#9
RJM1 diyAudio Member Join Date: Jan 2010 Location: Titusville, Fl.	You do know this is a 6 year old thread.