Bought an SMPS for amplifier use of eBay:
500W +/-70V Power Supply PSU Audio Amplifier AMP Board Use for Switching 648738810005 | eBay
50V version
Unfortunately I had made a mistake on my amp board turning a large diode the wrong way and probably causing the SMPS to blow.
I would have expected it to shot down by current limiting.
There was a 2W (SMD 2512) curent sensing resistor on the bottom which blew up, and it seems the primary windings are burned (they measur very littel resistance compared to a 70V version I also bought)!
On the 70V version there is two times same type SMD resistors in parallel .... both 0R1.
Can't tell what the singel one on the 50V version was as it was burned through.
Before I measured the primary, I tried to put the 2 resistors from the 70V version onto the 50V version. The result was both resistors burned and so did the half bridge fets (a piece broke of one :| )
Anyone tried these SMPS, and have good or bad experience?
/Baldin
500W +/-70V Power Supply PSU Audio Amplifier AMP Board Use for Switching 648738810005 | eBay
50V version
Unfortunately I had made a mistake on my amp board turning a large diode the wrong way and probably causing the SMPS to blow.
I would have expected it to shot down by current limiting.
There was a 2W (SMD 2512) curent sensing resistor on the bottom which blew up, and it seems the primary windings are burned (they measur very littel resistance compared to a 70V version I also bought)!
On the 70V version there is two times same type SMD resistors in parallel .... both 0R1.
Can't tell what the singel one on the 50V version was as it was burned through.
Before I measured the primary, I tried to put the 2 resistors from the 70V version onto the 50V version. The result was both resistors burned and so did the half bridge fets (a piece broke of one :| )
Anyone tried these SMPS, and have good or bad experience?
/Baldin
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wow, I wanted to buy this power supply last month but left that idea cause of lack of protection and the lack of quality capacitors and the weird thin traces by Y caps.
I started a thread where I'm will attempt to build my own SMPS.
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+1 The negative rail is shorted to ground... That's at least part of the problem, no?
No, the SMPS has both a dual supply at the high voltage as main PSP, it has a +-15 V regulated psp, with same ground as the primary, and a 12V regulated output with independent ground/zero. This is intended and used for Class-d amps where you need a driver voltage of ca 12V with reference to main Vss (minus). Therefore you connect the independent 0 to -V / Vss.
There is a white wire also to take this aux voltage before regulation, as I have the regulation on my amp board and need the littel higher voltage (+15V) ....
All voltages ofcourse tested before connection to the amp.
There is a white wire also to take this aux voltage before regulation, as I have the regulation on my amp board and need the littel higher voltage (+15V) ....
All voltages ofcourse tested before connection to the amp.
With all the sellers on eBay of this PSU, really no one her on the forum has experience with it?
I think overall the build quality is ok, but the controller and driver is built into a small black plastic house, and I have no idea of the construction ...
Reactance, don't really know what you mean by the "thin traces by Y caps" .... looks quite normal to me .... but again, haven't been working much with SMPS
The seller of the 70V one told me it had over current protection .... I guess that very few of the sellers know anything about these products, and thy just use the same badly translated description :| ...... I think it would be strange not to have somekind of protection .... and if not what is the resistor there for?
I think overall the build quality is ok, but the controller and driver is built into a small black plastic house, and I have no idea of the construction ...
Reactance, don't really know what you mean by the "thin traces by Y caps" .... looks quite normal to me .... but again, haven't been working much with SMPS
The seller of the 70V one told me it had over current protection .... I guess that very few of the sellers know anything about these products, and thy just use the same badly translated description :| ...... I think it would be strange not to have somekind of protection .... and if not what is the resistor there for?
I have four of these ebay power supplies (two 50V in a dual-mono, and two 40V in separate amplifiers) used in my class AB amplifiers. My experience with these power supplies is generally good. I have not tested them with a class D amplifier.
Pros:
- really cheap
- they actually work
- ripple and noise is quite good. I checked the output with 40 ohm load resistors and a scope. I did not see anything unusual. Although probably unnecessary, I did add an LC output filter.
- much smaller and lighter than conventional linear power supplies.
Cons:
- minimal implementation with no overload protection.
- cheap and mystery components. One of the 50V power supplies used 50V 1000uF output filter capacitors and the other used 63V 1000uF capacitors. They are all probably junk grade. I replaced them with Panasonic CE 63V 1000uF.
- The no-load voltage for all four power supplies are all different: 49V and 47V for the "50V" power supplies; 42V and 39V for the "40V" power supplies. Weird. These are unregulated power supplies so the output voltage depends upon your AC input and load.
Cresnet might be a better choice if you want a reasonably priced industrial strength SMPS power supply. I have not used their power supplies but I have seen considerable positive feedback.
That current sensing method is the worst I have ever seen.
Sometimes it work, most of the time it will not. Because it is not sensing both FETS.
However, you should expect anything from a Chinese SMPS.
If that was my SMPS, with blown FETS, you will be able to fix it in no time.
That's something we should consider when we buy a SMPS, in case if I blew the SMPS due some mistake, can I fix it myself? Or send it back and pay extra $? Send it to trash?
Hope that helps
Sometimes it work, most of the time it will not. Because it is not sensing both FETS.
However, you should expect anything from a Chinese SMPS.
If that was my SMPS, with blown FETS, you will be able to fix it in no time.
That's something we should consider when we buy a SMPS, in case if I blew the SMPS due some mistake, can I fix it myself? Or send it back and pay extra $? Send it to trash?
Hope that helps
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Hey Pronk
Good to hear. So they might work ok. I will try later with the 70V version, when I know for sure the amp works.
Yes Creanet, correct this is a poor design, and especially the safety side leaves much to be desired ... as just demonstrated.
And yes there bust be much better ways to do current sensing ... one way would be just to sense the current through the primary ....
Don't really have time to construct and build myself ... spending way too much time on my d-amps are taking too much time as it is
Will searchfor better alternatives, but if possible it needs to have same kind of outputs main +-V, aux +-15V (or 12V) and a 12V with separate 0 (zero) to be referenced to -V for a gate driver voltage
Good to hear. So they might work ok. I will try later with the 70V version, when I know for sure the amp works.
Yes Creanet, correct this is a poor design, and especially the safety side leaves much to be desired ... as just demonstrated.
And yes there bust be much better ways to do current sensing ... one way would be just to sense the current through the primary ....
Don't really have time to construct and build myself ... spending way too much time on my d-amps are taking too much time as it is
Will searchfor better alternatives, but if possible it needs to have same kind of outputs main +-V, aux +-15V (or 12V) and a 12V with separate 0 (zero) to be referenced to -V for a gate driver voltage
Interesting I looked at a Hypex SMPS and they use low side current shunt sensing from the -V bulk rail, no AC current sensing transformer, their circuit is very basic. the only thing interesting is the active rectification that uses transformer windings out of phase to manage timings instead of an IC.
Ok. Hypex is a no go then ... for those prices.
What about Connex Electronics?
I have 2 of the SMPS240QR PSUs, one running -60V and one +-40V. Seems lige quite
decent quality, and claim good protection?
The Connex ones are somewhat more expensive than the eBay run of the mill, but component and layout quality seems a lot better
I also had a look at this one 800W DC +/-70V Switching power supply for amplifier PSU /Stromversorgung GE | eBay any good??
What about Connex Electronics?
I have 2 of the SMPS240QR PSUs, one running -60V and one +-40V. Seems lige quite
decent quality, and claim good protection?
The Connex ones are somewhat more expensive than the eBay run of the mill, but component and layout quality seems a lot better
I also had a look at this one 800W DC +/-70V Switching power supply for amplifier PSU /Stromversorgung GE | eBay any good??
Ouch!
Speaking as an armchair SMPS designer myself I think you should be careful when trying to decipher a board layout then comparing what you do not know about with what you do not know about... especially when your lack of information and knowledge leads you to to the conclusion that Hypex does the same and is therefore also Dirt.
Speaking as an armchair SMPS designer myself I think you should be careful when trying to decipher a board layout then comparing what you do not know about with what you do not know about... especially when your lack of information and knowledge leads you to to the conclusion that Hypex does the same and is therefore also Dirt.
Good point. Don't know where Reactance has his information on Hypex from, and wheter it is correct or not.
Any information to the contrary is of course appreciated.
My point on it being no go, is that I'm trying to find a good alternative to the burned cheap SMPS, with at least better protection.
Price wise I think the Hypex ones are a bit expensive .... but quality often is
Good point. Don't know where Reactance has his information on Hypex from, and wheter it is correct or not.
Any information to the contrary is of course appreciated.
My point on it being no go, is that I'm trying to find a good alternative to the burned cheap SMPS, with at least better protection.
Price wise I think the Hypex ones are a bit expensive .... but quality often is
Sent you a PM.
Good point. Don't know where Reactance has his information on Hypex from, and wheter it is correct or not.
Any information to the contrary is of course appreciated.
My point on it being no go, is that I'm trying to find a good alternative to the burned cheap SMPS, with at least better protection.
Price wise I think the Hypex ones are a bit expensive .... but quality often is
I guess life is hard when you don't have the time to "roll your own", because you obviously can, and are left posting links to a random selection of E-Bay supplies and having to ask if they are any good.
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