A cheap SMPS for audio on ebay

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Hi ! i am eyeing this unit here

500W Amplifier Dual-voltage Audio Amp Switching Power Supply Board PSU AC100-240 | eBay

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the price is unbelievable for a 500W unit.
Is anyone direct experience with this power supply ?
the idea is to replace the linear one in a vintage Sansui au6900 amp i have at hand and of which i like the sound quite a lot.
Thanks a lot.
 
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I get meanwell 100 watts SMPS in enclosure for $25 here from electrical shops. This price after a few hands of suppliers and dealers and import duty etc. The Ebay price may be right for 500 watts open type for $30. You may have to add a cooling fan to avoid premature failure.
 
If its "cheap", "Chinese" or "ebay" then be very careful.

Hi ! thanks for the advice. Yes the price is ridiculous ... that cannot be that good. No brand ... i will skip.

I get meanwell 100 watts SMPS in enclosure for $25 here from electrical shops. This price after a few hands of suppliers and dealers and import duty etc. The Ebay price may be right for 500 watts open type for $30. You may have to add a cooling fan to avoid premature failure.

Hi ! thanks for the instructions. The idea was to try it in a little integrated and listen for the difference. I did not think about thermal issues ... that can make everything more tricky

I feel like the unit is a bit cheap compared to the same products that you can find all over the internet. I can say that it is a good deal though, considering the positive review from previous customers

Hi ! thanks for the reply. Problem is how much sincere they are ... maybe they are from the same company
I understand that smps quality is very different ... i opened some smps for pc and some were very poorly made. Other from Dell and Sony very nice looking inside ... the parts looked fine.
 
Be aware that there may be limited leakage protection and could be dangerous to use as the cheap products do not comply with standards expected to protect the consumer in safe use.
Make sure there is at least a 1/8" or 3mm air gap between the primary and secondary winding tags on the transformer and it uses class Y interference capacitors.
I note there is no photograph of any safety isolation. Use with care!
 
I have 1 (in fact 2 of them) - the first that arrived caught fire when connecting to mains. I contacted seller which didn't discus and I received a second one. It works pretty well, although initial voltage without load connected to it is quite high (appox. 4 volt above what is indicated). Can't comment though about safety.
 
Be aware that there may be limited leakage protection and could be dangerous to use as the cheap products do not comply with standards expected to protect the consumer in safe use.
Make sure there is at least a 1/8" or 3mm air gap between the primary and secondary winding tags on the transformer and it uses class Y interference capacitors.
I note there is no photograph of any safety isolation. Use with care!

Hi ! thanks for the precious advice. Better to be safe than sorry. I am skipping on the idea ... better not to play with safety. Thanks again.
 
I have 1 (in fact 2 of them) - the first that arrived caught fire when connecting to mains.
I contacted seller which didn't discus and I received a second one.
It works pretty well, although initial voltage without load connected to it is quite high (appox. 4 volt above what is indicated).
Can't comment though about safety

Hi thanks for the helpful information.
May i ask in which design are you using it ?
my curiosity started by noticing how rare are smps in audio amplifiers. Given that, i guess, a linear power supply is the most expensive part in an amp ... i do not understand why they are so rare.
Or maybe a very good one will have a price comparable to that one of a linear of same power ? so that there is no savings in the end ? i do not know.
I like very much their compactness and little weight ... the modular construction.
 
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SMPS is inherently somewhat noisier than a linear supply and depending on SMPS design the switching noise can be in the audible range (or have artefacts there). Whether that results in audible noise depends also on what you're powering with it. If noise on the rails is going to get through to the output, then you either need a very good SMPS, very good filtering or a linear supply. On the other hand, other amplifiers have very good power supply rejection - the Modulus86 amplifier discussed on this forum has exceptionally good noise figures but the designer states (and can back up with measurements) that a reasonable SMPS is no problem.
 
SMPS is inherently somewhat noisier than a linear supply and depending on SMPS design the switching noise can be in the audible range (or have artefacts there). Whether that results in audible noise depends also on what you're powering with it. If noise on the rails is going to get through to the output, then you either need a very good SMPS, very good filtering or a linear supply.
On the other hand, other amplifiers have very good power supply rejection - the Modulus86 amplifier discussed on this forum has exceptionally good noise figures but the designer states (and can back up with measurements) that a reasonable SMPS is no problem

Hi thank you very much ... i feel like i have open a can with some worms inside ... :eek:ok The fact that they are actually so rare should have told me something. :rolleyes: Then back to linear immediately. ;)
Thanks a lot again. :D
 
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