SMPS power supplies - are they really usable?

[Spasticteapot]

There's a guy on eBay selling surplus Lambda SMPS units that would work rather nicely for my project - they're good for +/-43V @ about 2 amps. Two of these would make for a fairly economical and efficient power supply, but I'm a little nervous about noise. Does anyone here have any experience with these?

Switching Power Supply 200W Dual +/-43V 2A -Audio Amp - eBay (item 170392013205 end time Jan-05-10 21:30:23 PST)

[star882]

It looks like a good power supply. It should work great.

[gootee]

Keep in mind that it's usually a lot easier to filter out an SMPS's switching frequency than it is to filter out 100/120 Hz from a linear power supply.

If you need to, you can add an LC or CLC low-pass filter to each SMPS output, and maybe even follow with a linear post-regulator. You should be able to get the noise down to tens of microvolts.

[godfrey]

Gotta love the documentation!
(available here: Hi )

Quote:
"Just for the record, I, the person providing this information, am a penniless peasant living in the mountains of Nepal."

Quote (regarding the power cable):
"Steal one from an old toaster or other broken appliance."

Quote (regarding shock hazard):
" It can give you a jolt hard enough to cause you to knock other things around on the bench, possibly causing a bigger fiasco."

[AP2]

Hi,
Only one is true dedicate for amplifier.
no EMI-No Ripple is DPS-600, ultra compact, see www.audiopower.it please.

Best Regards

[darkfenriz]

Looks nice, just a very basic forward converter.
Be carefull with adding any extra capacitance at output, it can become unstable.


to AP2:
please don't treat DIY forum as a free way to advertise what you're selling

[tiltedhalo]

I just thought I would throw in my two cents about these SMPS, I bought 10 of them a while back. Follow the mod sheets they will really help with high voltage regulation and adjust ability as they originally pulled the the adjust off the low voltage side, if you do not need the 3.3 and 5VDC remove them all together along with the analog board as it is not needed with the mods. I also replaced the barrel diodes in the HV side with to220 8amp high speed ones. As for noise they can use a little better filtering, but that is a simple fix better inductors and filters, as for added capacitance they seem to handle 20000MFD alright, no issues and I have had them running for over a year.
All in all if you have some parts in your parts bin and some time these make great little supplies. They will provide a constant 200W into a load as long as you keep them cool.

[microsim444]

This is good supply, Cant remember who manufacture those, Think they are china models
But it works. get it

[Spasticteapot]

Originally Posted by darkfenriz

Looks nice, just a very basic forward converter.
Be carefull with adding any extra capacitance at output, it can become unstable.

That's a bit worrying, as the application note for the amp basically says "Use REALLY BIG power supply caps". Is this less of a requirement if an SMPS is used?

[AP2]

Hi,

(To:darkfenriz)
I only pointed out a product that I consider very interesting. I do not sell! I would love to discuss and confront various circuit techniques, innovative instead of the usual 30 years old. must see .. flayback for audio amplifier? and other PSUs fall under voltage bursts (12-14Volt )?... nice! add capacitors?
I respect the work and passion of others.
----------------------------------------
SMPS for audio is critical, IMD, THD and noise are not easy to solve and then there's the issue of response time to the current. (Vital sign of a good amplifier) does not seem interested.
could address the problem by sharing the experiences of all of us.

Best Regards