Off the Shelf Power Supply?

[imloggedin]

Anyone have a recommendation for an off the shelf power supply (not DIY) which will provide -/0/+ anywhere between 9 to 18v? For example, a -15/0/+15 wall wart of some sort (not sure if that exists). Doesn't matter if its switch mode or linear. Thanks

 

[Matador]

Dual rail wall warts are incredibly rare.

I would look first at standard PC power supplies, which have +-12V rails...typically rated at at least a few amps each.

If those are too big, MeanWell sells small(er) stuffed PCB's that have dual rails. Google PD-2515. They are roughly the size of a 3x5 card and can be had for around $20. The rub with them is their hiccup mode, which means if you don't draw enough current they can be noisy in the audible range - but there are many threads on GDIY covering this already.

 

[ccaudle]

standard PC power supplies, which have +-12V rails...typically rated at at least a few amps each.

The -12V supply is really low current, and might not even be present on some systems. It was just used for the negative rail to a true RS-232 driver, and those are almost extinct these days. So don't count on a PC power supply to be useable for symmetrical rails.

Do you need it to be wall wart style?
Have you gone through the usual, like look through the Digikey selection menus? I found several that are not in a case, they are just bare power supplies that you would have to put in a case, wire up to an IEC input socket, fuse, etc.

Another option would be to find a single output wall-wart, then use one of the DC-DC converter modules to generate +/-15V from the 12V or 15V input from the wall-wart.

 

[ruffrecords]

Anyone have a recommendation for an off the shelf power supply (not DIY) which will provide -/0/+ anywhere between 9 to 18v? For example, a -15/0/+15 wall wart of some sort (not sure if that exists). Doesn't matter if its switch mode or linear. Thanks

A lot of Eurorack DIY synths work off a +- supply derived from an AC output wall wart/ I have seen designs for =_12 and +-15V regulated outputs.

Cheers

Ian

 

[pucho812]

Switcher PSU, +/-16VDC @ 2 AMP

Linear Power Supplies +/-15V 1.5A

the switcher listed above is the closest thing to a wall wart you may find.

 

[ccaudle]

This was listed at Digikey, but none in stock:
MeanWell triple output PS spec

 

[Script]

Lm317 lm337 psu dc 1.3v〜dc 25v

If you don't mind Chinese stuff, for anything drop-in, I look around on Alixpress.
Some offers are DIY, others just bare PCB, and some are readily built for quick drop-in.

Beware though that prices there vary a lot between sellers (it pays off to look around) -- so do shipping costs, and so do delivery times (to Japan between seven days to four weeks). Never had anything that did not arrive. Sometimes items from different sellers in same order come bundled, which can make shipping faster.

Not sure about import tax on items though imposed by your country.

 

[Bo Deadly]

This was listed at Digikey, but none in stock:
MeanWell triple output PS spec

That's been around for a long time but it's never in stock anywhere.

There are no off-the-shelf supplies that are adjustable over a 9-18V range. That would require a custom adjustable DC converter that would be difficult and possibly impossible to implement properly.

There is no practical solution for this particular scenario that I can think at this moment. My initial thought was to stack a bunch of SMPS and then use a mutli-pole switch to select taps and maybe simultaneously adjust regulators. But that's not what I would consider practical.

You could get two bench power supplies and then open them up and study them to see if they can be hacked into something useful. They are probably the right circuit. But conventional bench supplies tend to be quite noisy ironically. So again, not very practical.

 

[imloggedin]

Thanks for all of the suggestions. Just to clarify - I wasn't looking for a variable voltage supply, or anything with variable regulator, just something around the specified voltages. The CAPI one look exactly like what I want, except for the fact that its $95.

 

[Matt Syson]

Canford Audio (in the UK) HAD 15+15 'wall wart plug ins . I had one years ago.
A pair of wall warts is realistically the only 'cheap' non DIY option.
Matt S

 

[Matador]

The -12V supply is really low current, and might not even be present on some systems. It was just used for the negative rail to a true RS-232 driver, and those are almost extinct these days. So don't count on a PC power supply to be useable for symmetrical rails.

That depends on what your definition of 'really low current' is...the ATX specification requires -12V, and it's typical to have somewhere north of 300mA at minimum, which is (almost always) plenty for audio. You have to check the specs of course. Here is a typical spec sheet, and some have less (and some have more):

 

[Andy Peters]

This was listed at Digikey, but none in stock:
MeanWell triple output PS spec

Mouser has at least three variants in stock.

 

[Bo Deadly]

Mouser has at least three variants in stock.

Interesting. The E option is vaguely interesting but the currents are a little off and no 48V so still not ideal.

If a variable supply is not required, the usual solution is to just stack some SMPS. Of course there are many details that must be followed to make a really good pro-audio supply from SMPSs.

 

[iampoor1]

Mouser has at least three variants in stock.

Wouldnt we need a Class 1 power supply for safety? How would you do safety ground with a class II supply and a metal chassis?

 

[Scodiddly]

I just threw a Mean Well +24vdc into my build of the Hamptone JFET preamp - wow. Just dead quiet, no drama at all. $10 for a 15 watt supply. I will never build a linear supply again unless I need something with weird voltages.

 

[Brian Roth]

FWIW....I had some oddball noise when I used 2 or 3 Meanwells in a single build. Looking at crazy waveforms with the oscope I believe it's from the random...non sync...frequencies beating against each other.

On or off topic....I used to maintain several Neve Capricorn desks. I clearly recall seeing a "sync" line connected to the multiple SMPS units.

Bri

 

[Bo Deadly]

I just threw a Mean Well +24vdc into my build of the Hamptone JFET preamp - wow. Just dead quiet, no drama at all. $10 for a 15 watt supply. I will never build a linear supply again unless I need something with weird voltages.

That's not always the case. It is possible to make SMPS very quiet in almost any scenario. But there are implementation rules which have been discussed here are length multiple times.

 

[kohntark]

I just threw a Mean Well +24vdc into my build of the Hamptone JFET preamp - wow. Just dead quiet, no drama at all. $10 for a 15 watt supply. I will never build a linear supply again unless I need something with weird voltages.

Pardon for the thread necromancy, but I'm planning to build the FETBoy as my first preamp build and the power supply is puzzling me beyond belief.
I still have a lot to read.
Do you recall whether you got the RS-15 or HDR-15 model?