Hi, I bought this power supply form eBay. I blow it up with a short on the output. I replaced 2 FET transistors blown, and the back 0.1ohm R, but is not enough. Looks like the no-name black module between the caps and transistors is busted too.
404 Not Found
Is molded in epoxy and smashing it I could not figure the schematics.
Would be great appreciated s schematic for such Chinese power supply.
Thank you
404 Not Found
Is molded in epoxy and smashing it I could not figure the schematics.
Would be great appreciated s schematic for such Chinese power supply.
Thank you
The delivery time will somewhat depend on where you live. I got most of the items from Chinese sellers in 10-14 days if I stay with the well established sellers. Or at least those who had sold a lot of stuffs and keep good feedback.
For the PS, I found this for just over $30.
500W +/-70V High-power PSU Audio Amp Switching Power Supply Board Amplifier 648738745833 | eBay
Good luck.
Key features:
- No inrush current limiting NTC. (+50 cents.)
- Resin potted control circuit, not to hide any industrial secret. If it blows the average DIY-er won't be skilled to repair. (-$1 without potting.)
- Short life capacitors. As some caps start to dry the potted control circuit may blow. (+$5 for good capacitors.)
- No voltage regulation. Output drops like in conventional transformers. (+$2 for LLC inductor.)
- No current limiting. Make a short and potted control circuit will blow. (+$3 for proper control ICs.)
The product is lame. It is not lame for a matter of money. Imitators shall never fear to be imitated.
- No inrush current limiting NTC. (+50 cents.)
- Resin potted control circuit, not to hide any industrial secret. If it blows the average DIY-er won't be skilled to repair. (-$1 without potting.)
- Short life capacitors. As some caps start to dry the potted control circuit may blow. (+$5 for good capacitors.)
- No voltage regulation. Output drops like in conventional transformers. (+$2 for LLC inductor.)
- No current limiting. Make a short and potted control circuit will blow. (+$3 for proper control ICs.)
The product is lame. It is not lame for a matter of money. Imitators shall never fear to be imitated.
Eva, what do you think about this one.
High quality HIFI 800W SMPS +/-60V LLC Soft switching power supply board AMP PSU | eBay
High quality HIFI 800W SMPS +/-60V LLC Soft switching power supply board AMP PSU | eBay
It is for 220 volts input only. Not sure if it can be adapted for US.
The 700 watts one can be used with 110 volts AC input, but only outputs +/-35 volts DC.
Last edited:
Crap is still crap...
I'm sorry but there are many clues that depicts it's low quality.
Way too little capacitance, flimsy connectors, i have serious doubts about the layout, the power transformer and the heatsink...And as the other one, it is most probably a non user serviceable part...
A good quality high power supply will never be that cheap.
Then another drawback has to be assumed: The lack of an active PFC, which is a must for a SMPS of this output power in these days.
Best regards!
The promise of a "switching power supply" is in getting rid of the heavy and expensive power transformer and large capacitors. It works well in computer and other applications. Can it work for audio equipment? It is a big answer we like to discuss on this DIY forum. This vendor posted the real output voltage from 110 volts source and the following features:
Kay Pirinha raised an interesting question about the need of an active power factor correction circuit for protection when using a switching power supply. For computer use, I saw it mostly in the UPC box, not the computer PS itself. I wonder why?
We all know it is a jungle out there among the ebay sellers, but it is still one of the best source for DIYers as of today. Over the years, I got a few gems, and a lot of junks too. Unfortunately, some of the independent website sell the same gear at inflated price, which does not make them higher quality. The DIYer needs to have an adventurous spirit and willing to take some losses. You can search the posts I initiated for my failure and success stories.
It makes me feel really good when I made a cheap kit into good performance gear by some DIY mod. This thread on the ES9038Q2M is one of the good example of this.
Last edited:
Yes it can, i have designed, built and tested and sold many switching supplies for audio aplications, if they are well built they work ok and can last quite a long time. Trouble is, an audio amplifier is just about the worst load to a PSU, and high end components are expensive so many vendors cut corners and thus you get a bad quality supply.
LE: About that vendor in your link...
Not that you would ever need 500W from a +/-35V supply unit, but for the sake of argument let say you do.
Even at 90% efficiency, you would still loose more than 50W, and a rather large portion of that is on the power devices, specially on the rectifier diodes, so i ask you, could you dissipate that much power with those tiny heatsinks?
And there are many other clues that talks about it's quality, you just have to look for them.
Last edited:
Good to have an expert and designer to participate on this topic.
A name brand 600W computer power supply with active PFC goes for $40-120 in the US. Unfortunately, they have only 5 and 12 volts output. I wonder how much an audio switching PS will be. I can build an analogue PS for +/-60 volts DC output for about $150 using high quality toroidal transformer and Elna caps. An audio switch PS will have to beat than in cost to be commercially successful.
A name brand 600W computer power supply with active PFC goes for $40-120 in the US. Unfortunately, they have only 5 and 12 volts output. I wonder how much an audio switching PS will be. I can build an analogue PS for +/-60 volts DC output for about $150 using high quality toroidal transformer and Elna caps. An audio switch PS will have to beat than in cost to be commercially successful.
But your 60-0-60 switcher would need to be able to put out 50 amps for half a cycle at 20 Hz, repetitively, without misbehaving. 50 volts of swing, two ohms per channel, both channels driven. Long term output can be lower, but if the short term output can't handle it say goodbye to full power at 20 Hz. Computer supplies generally can't deal with that kind of overhead. They don't have to in the application. Big toroids have no problems with that kind of peak demand. A switcher that's up to the task is an entirely different animal and you're not going to get one for $150.
What you are saying is that switching PSU may be able to power audio amplifier in theory, but practical consideration will make it prohibitively expensive to implement. MarianB who makes and sells switching PSU for audio application seems to be saying the same thing.
Large wattage toroidal power transformer is very heavy. Making it impractical to import from oversea due to shipping cost. Fortunately, a few US supplier of quality transformer do exist. But finding a transformer with multiple dual output (a secondary output at lower amperage but 15% higher voltage for the voltage amplifier stage) has proven to be difficult.
Large wattage toroidal power transformer is very heavy. Making it impractical to import from oversea due to shipping cost. Fortunately, a few US supplier of quality transformer do exist. But finding a transformer with multiple dual output (a secondary output at lower amperage but 15% higher voltage for the voltage amplifier stage) has proven to be difficult.
Adding a pair of. 10 volt auxiliary windings to a big toroid is ridiculously easy. Just use insulated solid wire if you don't want to mess with magnet wire and another couple layers of Mylar tape.. Rectify and filter, add in series to the main rail, regulate if you want to.
Switchers for audio are not prohibitively expensive at low power. They just don't scale up easily. If a 200 watt unit is sufficient (for say a 50 watt amp or very light full range duty at 200 watts) it's not too expensive. But something that can legitimately power a 2kw PA amp (and not go into limiting ridiculously early, or be a ticking bomb) you do have to pay for. And building one yourself won't work the first time. Or the second.
Switchers for audio are not prohibitively expensive at low power. They just don't scale up easily. If a 200 watt unit is sufficient (for say a 50 watt amp or very light full range duty at 200 watts) it's not too expensive. But something that can legitimately power a 2kw PA amp (and not go into limiting ridiculously early, or be a ticking bomb) you do have to pay for. And building one yourself won't work the first time. Or the second.
The bottom line is that switching power supply for audio power amplifier offers no incentive to switch from linear power supply. A 200 watts toroidal transformer plus the rectifier and capacitors are relatively light weight, efficient and low cost to begin with.
The cheap switching PSU's just cannot do the job.
I have the same issue. the black module is not molded in epoxy, but rather in some sort of rubber foam. and the plastic walls are pretty soft. problem is that the IC inside has no markings in my case. could you please check yours inside maybe you can get a reading on IC. in the mean time I'm starting reverse engineering on schematic maybe we can figure it out
was able to find a very similar implementation and by checking the encapsulated board I'm pretty confident that the same circuit design was used
300w SMPS.png - Google Drive