I currently have six or eight of those wall-wart power supplies for various bits of hardware around my machine. There's probably four different voltages represented, and each one usually has a transformer getting nice and warm and chewing up extra power. And, of course, each one is just slightly bigger than the space allowed for it on a power board...

My solution would be to have one unit that had half a dozen leads that could be independently selected for voltage (3, 4.5, 6, 7.5, 9, 12 and 15 volts) and ring/tip polarity. This would be a switched-mode power supply so the efficiency would be nice and high and it wouldn't use much extra power just to keep itself humming. And if it was really good it'd have a separate power converter to present a range of DC voltages and then a bunch of daisy-chainable 'splitter' boxes that would provide the individual leads; so that if I got another device that needed a power supply I could just add an extra splitter box if I'd run out of cables on the first one.

Now, firstly, does anyone know of anything vaguely approximating this device? Does it work with 240V (as well as 120V)? Has anyone had any experience using it?

Seeing nothing like it that I can find in my local electronics stores, I think my next best option is to make my own. I would be building a switched-mode power supply with full circuit isolation, 120/240V switchable IEC input, and plenty of spare grunt for running empegs or (even) charging laptops. It'd be designed to take a lot of beating. It may take me a while to build, though, because I'm not a power supply whiz or even set up with my own electronics workshop. I do have the resources of hardware specialists at work though...

So the other two questions are: firstly, does anyone have any experience building switched-mode power supplies that they'd like to share with me? Secondly, for the rest of you out there plagued by wall-warts, is anyone interested in buying them if I can make them reliably?

And are there any extra features you would want in such a power supply?

Lots of questions here - now it's your turn to answer some of them!

Have fun,

Paul

I used to have to solve this problem for my pedalboard for my electric guitar (use a custom power supply built by a friend). Then I switched to rack-mount equipment and it's not an issue any more, but some rack gear uses wall warts as well...

Might want to check www.musiciansfriend.com ...

Heh, yeah, I figured guitarists would need this kind of thing.

Keyword search on "power supply" at Musician's Friend reveals some solutions (with limited voltage ranges).

I'd advise against building your own SMPS if you don't have much electronics experience. The component choices and design of the actual power supply isn't trivial. As you'll need a very high current supply the chances of it going kaboom with spectacular results are high. Patrick probably knows a lot more about this.

What I've done is to replace each individual linear power supply with a SMPS replacement. It's reduced the amount of clutter and they don't hum like the old ones did. I did briefly consider using a large prebuilt SMPS to power the lot but it would require a fan to cool. All of the ones I've got are made by SunPower

- Trevor

think knows lots about the kaboom bit

In reply to:

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I'd advise against building your own SMPS if you don't have much electronics experience. The component choices and design of the actual power supply isn't trivial.

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This is true. Fortunately I work for a company that has its own PCB hardware division, and the guy in charge has lent me a textbook on designing switched-mode power supplies. As I go about constructing it I'm going to show him what I'm doing and get his advice and/or assistance. I have worked with power circuits in the past - I built my own xenon strobe from a kit - so I'm not afraid, just out of practice.

My motivation for doing this is that it's probably going to cost me about the same to develop and build my own device as to replace all the wall-warts I have with switched-mode equivalents. And it seems to me that there's a market out there. However the lack of response from the people on this board, who I thought would similary plagued with wall-warts, has been less than encouraging.

Tony: Unfortunately many of them are 12V (like the empeg) or less than 6V (like my network switch). So a device like the Dunlop Brick you pointed out isn't going to solve my problem. I couldn't see anything else on the Musician's Friend site that fit the bill. Anyone?

Have fun,

Paul

Ah. If that's the case then go for it I've seen a few home built SMPS's that lost regulation once they had a load connected and then a huge bang as each of the capacitors blew.

My current count is 8 power supplies. A few of them are high power ones like my laptop and PC speaker amp but the rest are reasonably low current ones. It would save a lot of space by replacing them. Just getting rid of the huge multitap mains socket things would save a huge amount of space

All the best for this. It does sound like a good idea so don't get discouraged.

- Trevor

If 12V is the highest you need to go, then you could always use an AT PSU from an old PC, which supplies 12V and 5V at reasonable current.

I have one mounted in a box with trailing cables for all my stuff, anything I have that needs something other than 5 or 12 volts is pretty low current so gets taken care of by a voltage regulator.

Just counting - in my music room I have 14 of these, mostly at 12v, some at 9v, one at 18v and one at 24v. If you end up with an easy to follow circuit diagram, I'd be interested to see it, if that's okay?

The problem with an AT PSU is that they've all got fans and disabling them may cause it to overheat.
They are the only cheap PSU's that is easily found that have a high current capabiility though.

- Trevor

I have that many machines running in the corner of my office, that one more fan makes very little differance. If anything it just means I need to turn the music up a little