Using 2 x Meanwell SMPS to get +ve 0v -ve

[firestorm]

I need +40 -0v -40v at about 4amps per rail.

Instead of using a traditional 500VA 30-0-30 toroidal transformer, rectifier and psu caps, can anyone think of any problems using 2 x Meanwell 36V 350W smps ? The smps have 10% adjustment on the Vout.

Wired as +40v 0v....40v 0v


to give +40 -0v -40v ?

I know it should work in theory, does it hold true in practice?

Thanks
fs

[madtecchy]

What will this psu supply.

[firestorm]

a 50w class amp, it needs a bipolar supply.

[Andrew Eckhardt]

A real answer requires a circuit diagram or knowledge of it. It probably has a fully isolated output but if it has that it should say in the datasheet. It's kindofa big sales point sort of thing.

[firestorm]

I've found some more info on the smps, the guy has two of them connected in parallel and one in series for charging LiPo batteries. I've read the information, but I'm still not 100% sure if I can use it + 0 - configuration.

Endless-sphere.com • View topic - How-To: Meanwell 63-84V CV/CC Charger

[Andrew Eckhardt]

Looks like you're good to go with that circuit. The outputs labeled + and - V is usually a good indicator that you have isolated outputs / can stack a few / make a split supply out of them.

[benb]

Yes, the outputs are isolated and you can put the outputs in series to make +/- voltages.

Here's a list of models, you can find whatever you've got and look at the datasheet:
Switching Power Supply - Mean Well Switching Power Supply Manufacturer
I've got a couple different models of these, they're just like any other such supply, the outputs are isolated from the "primary" and the chassis.

[firestorm]

Hi Ben
Thanks for the confirmation. Do you know if I can operate these in constant current mode, so that for instance I can draw 350w into a low R situation and not trip the over current protection?

Also do you have any experience in making the psu quieter for audio applications?

Thanks

[benb]

I've not use these to power an audio amplifier.

That page you pointed to earlier apparently discusses using it in current mode, but I don't know how current mode would apply to running an audio power amplifier.

As far as noise, not sure which you mean. there's acoustic noise - these things have cooling fans, but I doubt it would come on unless you play a modern hypercompressed "brickwalled" CD at full volume, and then you won't be able to hear the fan running anyway.

There's without a doubt a lot of electical noise in the outputs of these things. It's the kind of thing that's hard to eliminate, but some high-frequency L-C filtering should help. I could only guess at a first-approximation circuit and component values, maybe someone with more experience at that can help.

[firestorm]

Originally Posted by benb

That page you pointed to earlier apparently discusses using it in current mode, but I don't know how current mode would apply to running an audio power amplifier.

My rationale for operating it in constant current mode would be to allow it to work at Imax into low Rload where it doesn't suddenly shutdown when the design current is breached, such as sizeable reservoir capacitors. I am hoping in conjunction with smoothing capacitors, the psu is able to supply considerably higher current peaks.

Thanks for your input.