MFOS Adjustable 1.5A Bipolar Power Supply Transformer Help

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valis
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MFOS Adjustable 1.5A Bipolar Power Supply Transformer Help

Post by valis » Tue Mar 09, 2010 1:18 am

Greetings,

I need a +/-9v PSU and it seems like the best option is the MFOS "Adjustable 1.5A Bipolar Power Supply PCB." I have a Condor PSU that I configured but I've never picked out a transformer and am pretty ignorant on the subject. I'm going to be placing a Mouser order and would absolutely love a lead on a transformer. I'm looking for "a transformer with a center tapped 24VAC to 26VAC." I would really hate to order the wrong transformer and go through the whole troubleshooting process.

Also, how will I know what size fuse to get?

Thanks for reading!

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Luka
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Post by Luka » Tue Mar 09, 2010 1:27 am

i would think that using a transformer that large will generate a lot of heat considering your desired output voltages.

i wouldnt bother using a lm317 based power supply, just something like this http://www.cgs.synth.net/modules/cgs14_psu.html and then use 7809 / 7819 regulators in place of the 7815 / 7915. Then use a transformer that outputs about 9 - 12V ac

this is just a practice ive picked up over time so perhaps someone could suggest something more robust or more suitable

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valis
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Post by valis » Tue Mar 09, 2010 1:35 am

Luka wrote:i would think that using a transformer that large will generate a lot of heat considering your desired output voltages.

i wouldnt bother using a lm317 based power supply, just something like this http://www.cgs.synth.net/modules/cgs14_psu.html and then use 7809 / 7819 regulators in place of the 7815 / 7915. Then use a transformer that outputs about 9 - 12V ac

this is just a practice ive picked up over time so perhaps someone could suggest something more robust or more suitable
Yeah, the CGS014 has been discontinued and I don't really want to perf board the whole thing. There doesn't seem to be a lot of options for somebody needing a durable +/-9v that they can gig with..

Ray does recommend using large heat sinks but I'm open to any psu suggestions..

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RF
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Post by RF » Tue Mar 09, 2010 7:01 am

FWIW - I think Perfboarding a low current bi-polar power supply with 78xx and 79xx regulators is about the easiest perf project one could imagine...

bruce
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bananeurysm
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Post by bananeurysm » Tue Mar 09, 2010 3:28 pm

what about a couple 9v batteries?

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valis
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Post by valis » Tue Mar 09, 2010 3:49 pm

bananeurysm wrote:what about a couple 9v batteries?
Sadly no, I have quite a few modules that run at +/-9v. I'd need at least 400-500ma.

dl

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Post by Luka » Tue Mar 09, 2010 4:04 pm

are you powering these in the same cabinet as 12 or 15v modules?

if so you could just get some 9v regulators and make a little distro board with reduced voltage. regulators are easy to set up. they just need an input voltage, ground and then the output voltage comes out the other leg

Image

for +9v use a 7809, -9 uses a 7909

if you a using a 15v supply you will need heat sinks, if 12v it should be ok

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valis
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Post by valis » Tue Mar 09, 2010 4:10 pm

Yeah, it's complicated. I am powering this on the same cabinet as a +/-15v supply but my amps are pretty limited there. I breadboarded a 7809/7909 circuit but after much debate, I'd prefer a dedicated +/-9v supply. I'm building this supply into a box with that will serve as a...

... Well, it's complicated but be assured that I have weighed all the practical options. I'm going to do a dedicated +/-9v supply one way or another..

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Post by Luka » Tue Mar 09, 2010 6:50 pm

ok well just go with your original idea but lower the transformer output voltage to 12v or 15v

http://www.alliedelec.com/search/produc ... KU=9670192

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