Switching power supplies?

barendh · 15th February 2007, 10:37 AM

Searched, but could not really find an answer...

Got this Outlaw Audio 7*200W final amp from the USA, weighing over 50kg and working from 115VAC.
After a lot of brain activity here I concluded there is no easy way to convert this to our 230VAC, as the two gigantic toroidals aren't identical, so merely wiring the primaries will not work.
Besides, the weight makes the amp difficult to handle...

However, the (linear) 7 boards are really very nicely made and fully balanced, too nice really to leave gathering dust...

Which made me think, are there any small switching supplies around that output approximately 28-0-28VAC, or do they all output DC only?
I already asked Coldamp, and as usual got a very friendly and helpful answer already, but their supplies, beautiful as they are, do not supply AC, but could be converted to 40VDC*2, which I will probably attempt should all else fail.

Suppose I would need 2 or 3 smps supplies of 400W.

Thanks for thinking with me!

Barend (Holland)

richie00boy · 15th February 2007, 10:52 AM

Are you sure the primaries are not 2x 110v currently wired in parallel, which can be wired in series?

barendh · 15th February 2007, 10:58 AM

Yes they were, and in my innocence I tried wiring them in series, but that gave me 75V on one on 130V on the other primary, because one toroid supplied 4 amps and the other seven...
Adding a forcing toroidal 0-115-230 across the three points 0-115.
115-0 improved this 75-130 to 108-120 but added even more more weight...

So I see only the option of working with a switching supply...

lucpes · 15th February 2007, 11:08 AM

How about getting a 1.5KVA 220Vac to 110Vac transformer to supply the amp with? Or get two toroids with the corresponding voltages, they're much cheaper than getting SMPS's.

barendh · 15th February 2007, 11:27 AM

No, because a) I don't want a humming beast of a stepup transformer in my living room and b) I don''t want the heavy weight...

richie00boy · 15th February 2007, 11:48 AM

Quote:

Originally posted by barendh
Yes they were, and in my innocence I tried wiring them in series, but that gave me 75V on one on 130V on the other primary, because one toroid supplied 4 amps and the other seven...

No I meant was one of the toroids with 4 wires primary wires coming off it, with two primaries wired in parallel.

Quote:

Originally posted by barendh
So I see only the option of working with a switching supply...

Why not just replace the transformers with ones with suitable primaries? Would be a lot easier!

15th February 2007, 10:37 AM	#1
barendh diyAudio Member Join Date: Sep 2006	Switching power supplies? Searched, but could not really find an answer... Got this Outlaw Audio 7200W final amp from the USA, weighing over 50kg and working from 115VAC. After a lot of brain activity here I concluded there is no easy way to convert this to our 230VAC, as the two gigantic toroidals aren't identical, so merely wiring the primaries will not work. Besides, the weight makes the amp difficult to handle... However, the (linear) 7 boards are really very nicely made and fully balanced, too nice really to leave gathering dust... Which made me think, are there any small switching supplies around that output approximately 28-0-28VAC, or do they all output DC only? I already asked Coldamp, and as usual got a very friendly and helpful answer already, but their supplies, beautiful as they are, do not supply AC, but could be converted to 40VDC2, which I will probably attempt should all else fail. Suppose I would need 2 or 3 smps supplies of 400W. Thanks for thinking with me! Barend (Holland)

15th February 2007, 10:52 AM	#2
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Are you sure the primaries are not 2x 110v currently wired in parallel, which can be wired in series? __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

15th February 2007, 10:58 AM	#3
barendh diyAudio Member Join Date: Sep 2006	115V Yes they were, and in my innocence I tried wiring them in series, but that gave me 75V on one on 130V on the other primary, because one toroid supplied 4 amps and the other seven... Adding a forcing toroidal 0-115-230 across the three points 0-115. 115-0 improved this 75-130 to 108-120 but added even more more weight... So I see only the option of working with a switching supply...

15th February 2007, 11:08 AM	#4
lucpes diyAudio Member Join Date: Dec 2003 Location: Iasi	How about getting a 1.5KVA 220Vac to 110Vac transformer to supply the amp with? Or get two toroids with the corresponding voltages, they're much cheaper than getting SMPS's. __________________ Deep down inside.

15th February 2007, 11:27 AM	#5
barendh diyAudio Member Join Date: Sep 2006	115V No, because a) I don't want a humming beast of a stepup transformer in my living room and b) I don''t want the heavy weight...


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