I need to build a power supply that can power 2 LM3886 at full power, no matter in normal mode, or bridged mode. I just can't afford that large of a transformer, so thought about designing a switching power supply. I have never worked off the ac line before, so that worries me a bit, but I am sure it would be fine. I have a old Dell PS from a computer, which after tearing it apart thinking it was broken, I found the fuse. So I should be able to get parts for it. Can anybody help me design this? I need 48VCT @ about 10A.
Thanks, Mike
Thanks, Mike
I had the same idea a while back you might want to check out this link.
http://diyaudio.com/forums/showthread.php?threadid=15055&highlight=
http://diyaudio.com/forums/showthread.php?threadid=15055&highlight=
Hi speed,
The posts you sent me to was about 12VDC operated switching supplies.
My application is in a subwoofer, so I need 120VAC operation.
The following is a list of parts I tore out of the PC supply, exactly what the chips say:
1. ST 9448
Malaysia
P3N90
2. CTB34D
-|>|--|<|- (two diodes)
40 28
3. C92W
-|>|--|<|- (two diodes)
82
4. 37-C5151103
9422C
5. 42-M52211P02 HP OK
LITEON 9452 JC
6. 42-M51511P03 HP OK
LITEON 9504 JC
7 and 8. L7905CV
W991J9427
MALAYSIA
ST
9. LT KBJ406G
10. a coil wound around a metal circle with 12 pins
labeled 37-C5151102
9422C
and on the plastic bottom, BASE-07-1
Hopefully these parts are useful, and hopefully i didn't just waste 5 minutes entering them in.
1-3 are transistors
4-6 are transformers
7-8 are transistors (possibly 7805 regulators?)
9 is a bridge rectifier
Thanks for the help
The posts you sent me to was about 12VDC operated switching supplies.
My application is in a subwoofer, so I need 120VAC operation.
The following is a list of parts I tore out of the PC supply, exactly what the chips say:
1. ST 9448
Malaysia
P3N90
2. CTB34D
-|>|--|<|- (two diodes)
40 28
3. C92W
-|>|--|<|- (two diodes)
82
4. 37-C5151103
9422C
5. 42-M52211P02 HP OK
LITEON 9452 JC
6. 42-M51511P03 HP OK
LITEON 9504 JC
7 and 8. L7905CV
W991J9427
MALAYSIA
ST
9. LT KBJ406G
10. a coil wound around a metal circle with 12 pins
labeled 37-C5151102
9422C
and on the plastic bottom, BASE-07-1
Hopefully these parts are useful, and hopefully i didn't just waste 5 minutes entering them in.
1-3 are transistors
4-6 are transformers
7-8 are transistors (possibly 7805 regulators?)
9 is a bridge rectifier
Thanks for the help
yeah...I'll bet after u built the SMPSU and got it to work...it will exceed the price of a full trafo with caps...plus the SMPSU will give a lot of interference due to the switching involved...wouldn't really recommend it...but if you wanna do it for fun...by all means go ahead...I've seen some SMPSUs (they are not for PCs) that have a +/-24V output after tweaking...check out this site here for a bit of info (though he used them for a Laser supply) I think it's pretty cool.
http://www.electricstuff.co.uk/argonlaser.html
http://www.electricstuff.co.uk/argonlaser.html
don't forget
to consult www.mpja.com
sometimes interesting deals.... but you need to be fast, they are always running out of stuff faster than you can think
besides apexjr.com ...
J-P
to consult www.mpja.com
sometimes interesting deals.... but you need to be fast, they are always running out of stuff faster than you can think
besides apexjr.com ...
J-P
I bought a
Toroid 44 - 0 - 44 volt 8 A
first thought it would be too much but the specs from nat semi told me it would be OK , the DC is about 62 volts
The amp never runs out of power
I bought 3 of them at All Electronics, they were dirt cheap and had been removed from existing merchandise. At $22 a piece they are really a good deal.
I was wondering if your solution could be connecting 2 transfo's to jack up the voltage upto a descent #
like
12 v / 0 + 12 v / 0 v
in this case ou would get 24 volts ....... just be sure you have enough A.
Toroid 44 - 0 - 44 volt 8 A
first thought it would be too much but the specs from nat semi told me it would be OK , the DC is about 62 volts
The amp never runs out of power
I bought 3 of them at All Electronics, they were dirt cheap and had been removed from existing merchandise. At $22 a piece they are really a good deal.
I was wondering if your solution could be connecting 2 transfo's to jack up the voltage upto a descent #
like
12 v / 0 + 12 v / 0 v
in this case ou would get 24 volts ....... just be sure you have enough A.
If you have a working 120 VAC SMPS you can get whatever voltage you want from it, if you are willing to wind your own transformer or have a source for one. You need to watch the ratios of primary and secondary, and recalibrate the voltage regulation on the controllers.
I have never done this myself, but know someone who has. It is extremely dangerous and best left to people who know how to operate with high voltages. Switching power supplies are much more complex than a simple transformer, and more dangerous as well.
It would be good if you could source two smaller transformers of half the voltage, and connect them in series. Or have two transformers, one for each chip. A 150VA transformer cannot be very expensive, at least in comparison to what you are about to attempt.
I have never done this myself, but know someone who has. It is extremely dangerous and best left to people who know how to operate with high voltages. Switching power supplies are much more complex than a simple transformer, and more dangerous as well.
It would be good if you could source two smaller transformers of half the voltage, and connect them in series. Or have two transformers, one for each chip. A 150VA transformer cannot be very expensive, at least in comparison to what you are about to attempt.
Why don't all you LM3886 fans join up and form a club. If you go together and buy say 300 transformers all together, you can get real good ones, custom made to exactly fit your requirements.
You can make it so it gives your +/- 35V 200 VA or bigger, if you wish.
A transformer like that would cost less than 15$ (depending on size) from a supply'er i China (with UL listing and all). And the quality is really good too.
You can make it so it gives your +/- 35V 200 VA or bigger, if you wish.
A transformer like that would cost less than 15$ (depending on size) from a supply'er i China (with UL listing and all). And the quality is really good too.
Well, it has 4 of them.
one is about an inch cube, yellow an made by Liteon. it has 3 pins on one side and 7 on the other.
the second is Also made by Liteon. it is about an inch tall and 1/2 inch long and deep.
The third doesn't say who it is made by, but is about the same size as the last one, but just a little shorter and wider.
Fourth is a torrid about a 1 1/4 inch thick including the windings, and had multiple wires wound around it. 6 pins on each side.
I have a 10VAC 10VA transformer, so I can safely test these to see what the ratio is.
one is about an inch cube, yellow an made by Liteon. it has 3 pins on one side and 7 on the other.
the second is Also made by Liteon. it is about an inch tall and 1/2 inch long and deep.
The third doesn't say who it is made by, but is about the same size as the last one, but just a little shorter and wider.
Fourth is a torrid about a 1 1/4 inch thick including the windings, and had multiple wires wound around it. 6 pins on each side.
I have a 10VAC 10VA transformer, so I can safely test these to see what the ratio is.
Ranting to the max, but for good purpose.
/Circlotron - preaching fire and brimstone
but switchers *can* be as dangerous as guns.
Good point Sangram, I'll second that. soundNERD, not trying to sound condescending but *dont do it*. Quite apart from the fact that the learning curve is awfully steep and that you will have so many blowups that by the time you get something working you will be deaf from all the explosions, it is truly WAY more dangerous than a transformer type supply. Like most people on this forum I just mess around with audio stuff for fun, but I spend my working days in an SMPS design lab so I get to see first hand all that goes into designing and building a safe supply. A switcher that runs of the AC mains is NOT the sort of thing that you want to feel your way through. (unlike 12v operated ones) The mains and a good chunk of the switcher cct is a high voltage, low impedance source of fire, explosions, personal injury and death (to maybe some other than yourself). All my amps have had conventional power supplies even though I could make an ok switcher if I decided to.sangram said:
/Circlotron - preaching fire and brimstone
but switchers *can* be as dangerous as guns.
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