Multi voltage switched PSU

[RuudNL]

Is there a manufacturer that produces switched mode PSU's with multiple voltage outputs?
I need one with + and - 15 V (1.5 A), +5 V (1 A) and +48 V (0.25 A)
As far as I know many 'budget' mixers use such a PSU (Phonic, Behringer, Mackie)
So they must be produced somewhere....

 

[JohnRoberts]

I haven't seen any such dedicated product.

The pro audio console business may not be large enough to support such a dedicated IC design.  IC mic preamps (that don't suck) are a relatively recent development.

The relatively low volume console market likes universal mains voltage capability, so one SKU can support world markets.  Mixed technology (5V digital, and +/-15V analog  supplies) would be an even smaller fraction, of the already small market. How much current gets allocated to which supply, and other questions?

I would be tempted to suggest cobbling together a 5V switcher, with a +/-15V switcher , and +48V switching supplies fed from a common unregulated PS. You could sync at least one edge of the clocks together but layout and filtering would be important.

Peavey was just getting into using switchers (for consoles) around the time i left. While there was a switcher used for just the 48V rail in the old Mark VIII live console, maybe 10 years earlier. 

JR

 

[RuudNL]

This is an example of a switched mode power supply used in a lot of 'budget' mixers. (By Mackie, Behringer, Phonic etc.)

 

[JohnRoberts]

Well use that then... after my time.

Looks like maybe the +15V is reg and all the others track that.

Probably close enough for government work.

JR

 

[RuudNL]

I would like to use one of those, if I would know where to buy them...

 

[sahib]

I don't think you can get them off-the-shelf  as there is not sufficient demand as stand-alone units.

 

[RuudNL]

Come on! Behringer, Mackie and Phonic all use the same power supply and I am sure that they don't produce those PSU's themselves, so there must be a manufacturer making them!
(Unfortunately these companies are not willing to sell me one or two units as a replacement part.)

 

[sahib]

You got me wrong. I meant as retail.

They are oem customers and probably licenced the design. You can get designs complete with the pcb layout to drop into your own pcb designs.

Even if you found the company I doubt they'll sell you one. But you may pretend to be a manufacturer and ask for a sample for evaluation.

 

[kibadachi]

Meanwell and Umec deliver multi voltage PSUs.
If your location is the Netherlands check Distrelec( formerly Display utrecht area) They deliver Meanwell for reasonable prices

 

[zayance]

Didn't you got yourself a Custom Toroidal for the same application?

 

[JohnRoberts]

Come on! Behringer, Mackie and Phonic all use the same power supply and I am sure that they don't produce those PSU's themselves, so there must be a manufacturer making them!
(Unfortunately these companies are not willing to sell me one or two units as a replacement part.)

You don't think those manufacturers make their own power supplies? The last time I checked they were all price sensitive value product makers. A power supply is exactly the low tech subassembly they would make themselves to save money on.

The unique part in that design looks like the transformer and companies of that size and manufacturing scale routinely specify their own custom iron. While the volume may be small for PS makers to offer a standard product, a mixer manufacturer could justify the custom transformer. The rest of the design looks like common parts assembled to make a multi output PS.

The actual regulator looks like it's only regulating one output voltage. I've seen switchers that regulate two output voltages at the same time (I actually removed one from a design because the transformer was so noisy).

If these are common off the shelf parts, like you suggest, you'd be able to find them. I have never seen one, in my sundry searches of switching supplies, while I haven't been looking for exactly that. 

JR

PS: Perhaps buy a behringer (or phonic, or mackie) pull out the PS and throw away the mixer.  8)

 

[Harpo]

Something like this ? maybe.
(never used one of these myself)

 

[RuudNL]

Didn't you got yourself a Custom Toroidal for the same application?

Yes! I produced a linear power supply with it. The guys in France did a perfect job!
But now I need a couple of small power supplies with multiple voltages.

 

[PRR]

> looks like it's only regulating one output voltage.

The +15 output is not regulated.... it has a 2K2 filter and Darlington pass element. It is getting +16.5V (computed from R15 R17 and '431 reference).

The +16.5V is regulated.

The -16.5V has the same number of turns and thus the same induced voltage. At HF the winding losses may be quite small, so -16.5V load regulation is good.

The +12V and +5V likewise have turns proportional to the +16.5V winding and thus good regulation.

This is all the same (except turns-count) as a PC power supply. The reference sees the PC's +3.3V line and holds it. +5V, +12V, and the minor outputs tend to follow within tolerable sag.

The +48V output is actually regulated by 47V Zener and another pass transistor. (Note that this may be +46V; also C19 47V is across a 47V zener with zero safety factor.)

For just a +/-15V and 48V, there are table-wart +/-15V supplies and you can buzz-up 48V yourself with some CMOS or even a 5532 and a voltage multiplier. Nearly all low-price 1 or 2 channel mike boxes make their Phantom this way.

 

[Andy Peters]

This is an example of a switched mode power supply used in a lot of 'budget' mixers. (By Mackie, Behringer, Phonic etc.)

Is that supply in a separate enclosure or is it built into the mixer chassis?

If it's the latter (and it is), then the parts are on the main PCB so it's not a separate unit.

-a

 

[RuudNL]

@Andy Peters: The PSU is inside the mixer, but it is a 'module'  that looks different than the mixer itself (other PCB colour, different - rather crappy- construction etc.), so this gives the impression that the PSU is manufactured by a different company. No text on the module or PCB unfortunately.

@PRR: thanks for your excellent explanation! It is always a pleasure to read your comments.
They show an extensive theoretical background combined with a lot of practical experience (and humour!).
By the way: I measured the voltage and it is almost exactly 15 V. Not 16,5 V.
The phantom power voltage is indeed a bit lower than 48V, but I think it is still within specification.
Anyway, I never had problems with 46 V. phantom power.
(I once used the same approach in one of my own designs.)