computer power supply

rev_psilocybe · 3rd May 2005, 09:22 PM

What is the possibility of using a 4-500 watt regulated computer (ATX) power supply for some of these 12VDC chip amps? Is it possible? Is the line noise that horrible?

neutron7 · 4th May 2005, 06:42 AM

if you used some extra capacitors near the chip, it should be good enough for TDA type chips. dont expect too much from them though.

imix500 · 4th May 2005, 06:47 AM

also remember that you will probably have to load the primary (5v) rail to keep the supply happy.

rev_psilocybe · 4th May 2005, 07:36 AM

thanks for the feedback, much appreciated!

Now that I know it's possible I'll throw something together and what happens. I'm sure I can keep that 5V happy with a few LEDS.

I've used one previously to run a 100watt car amp bridged to drive a 12" horn sub. Little noisy on startup but worked flawlessly every gig. And that was a PSU with those damn bad Caps that got into everything a few years back.

thanks again!

neutron7 · 5th May 2005, 05:41 AM

you could power quite a few with this

http://www.pcpowercooling.com/about/whatnew_850_ETX.htm

" Four +12V rails @ 17A ea. (12V1-V4=54A/62A pk.) "

rev_psilocybe · 5th May 2005, 07:42 AM

one more question! Woud it be possible to simmply connect the +12, +5, -5, -12, and GRND of 2 PSUs together to get 24v?

Giaime · 5th May 2005, 01:57 PM

Quote:

Originally posted by rev_psilocybe
one more question! Woud it be possible to simmply connect the +12, +5, -5, -12, and GRND of 2 PSUs together to get 24v?

Mmmmm... I think you're looking for smoke

indoubt · 5th May 2005, 03:54 PM

I've used a PC PSU to power an old carradio. The PSU is modified with a 10.000uF cap, a small bypass cap and a 17Watt resistor on the 5V to keep the supply from shutting down.

It works, it even works reasonable well after adding the capacitance but I don't think it will be as good as a regular supply. It remains a little noisy alhough the fan drops in speed after a minute or so because the supply is operating far from max.

Don't connect the other wires to get 24 Volt, I think they have a common ground ro zero and then you shortcut the thing instantaniously. different PSU might have different topologies though.

dnsey · 5th May 2005, 04:53 PM

I'm currently using a computer PSU to provide + & - 12V supplies for a commercial (Fender) mixer. No dummy load on the PSU, and very little supply filtering in the mixer. Perfectly reliable, and no audible noise through a 200W a side amp.

rev_psilocybe · 6th May 2005, 06:18 AM

Quote:

Originally posted by dnsey
I'm currently using a computer PSU to provide + & - 12V supplies for a commercial (Fender) mixer. No dummy load on the PSU, and very little supply filtering in the mixer. Perfectly reliable, and no audible noise through a 200W a side amp.

Did you modify your PSU at all? What rating? 250 -500w?

I never had to dummy load the 5v on mine either, just short the remote turn on wire to a ground. I'm getting the feeling this 5v dummy stuff is only for AT power supplys...

3rd May 2005, 09:22 PM	#1
rev_psilocybe diyAudio Member Join Date: May 2005 Location: Houston,TX	computer power supply What is the possibility of using a 4-500 watt regulated computer (ATX) power supply for some of these 12VDC chip amps? Is it possible? Is the line noise that horrible?

5th May 2005, 03:54 PM	#8
indoubt diyAudio Member Join Date: Aug 2003 Location: Sweet lake city	I've used a PC PSU to power an old carradio. The PSU is modified with a 10.000uF cap, a small bypass cap and a 17Watt resistor on the 5V to keep the supply from shutting down. It works, it even works reasonable well after adding the capacitance but I don't think it will be as good as a regular supply. It remains a little noisy alhough the fan drops in speed after a minute or so because the supply is operating far from max. Don't connect the other wires to get 24 Volt, I think they have a common ground ro zero and then you shortcut the thing instantaniously. different PSU might have different topologies though. __________________ better be indoubt untill you're sure

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4th May 2005, 06:42 AM	#2
neutron7 diyAudio Member Join Date: Dec 2003 Location: Toronto Canada	if you used some extra capacitors near the chip, it should be good enough for TDA type chips. dont expect too much from them though.

4th May 2005, 06:47 AM	#3
imix500 diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	also remember that you will probably have to load the primary (5v) rail to keep the supply happy.

4th May 2005, 07:36 AM	#4
rev_psilocybe diyAudio Member Join Date: May 2005 Location: Houston,TX	thanks for the feedback, much appreciated! Now that I know it's possible I'll throw something together and what happens. I'm sure I can keep that 5V happy with a few LEDS. I've used one previously to run a 100watt car amp bridged to drive a 12" horn sub. Little noisy on startup but worked flawlessly every gig. And that was a PSU with those damn bad Caps that got into everything a few years back. thanks again!

5th May 2005, 05:41 AM	#5
neutron7 diyAudio Member Join Date: Dec 2003 Location: Toronto Canada	you could power quite a few with this http://www.pcpowercooling.com/about/whatnew_850_ETX.htm " Four +12V rails @ 17A ea. (12V1-V4=54A/62A pk.) "

5th May 2005, 07:42 AM	#6
rev_psilocybe diyAudio Member Join Date: May 2005 Location: Houston,TX	one more question! Woud it be possible to simmply connect the +12, +5, -5, -12, and GRND of 2 PSUs together to get 24v?

5th May 2005, 04:53 PM	#9
dnsey diyAudio Member Join Date: Mar 2004 Location: Shropshire, England	I'm currently using a computer PSU to provide + & - 12V supplies for a commercial (Fender) mixer. No dummy load on the PSU, and very little supply filtering in the mixer. Perfectly reliable, and no audible noise through a 200W a side amp.