Hey people,
I've got an adjustable SMPS with max. 48V/ 10A, bought at Amazon, brand/ model is "HJS-480-0-48". I want to use it as power supply for a class-D amp in stereo BTL mode driving two 6.5" Midwoofers (atm. I've got 5.25" midwoofers driven by LM3886 chipamps which are really loud enough (max. 60%, never tried more) but I just want to move more air). I think, I'd never really torture the PSU, but I've read a (or maybe two) review(s) where this specific SMPS broke down when driven near the max. current.
As I made a few little modifications (bigger & slower fan, internal mains power connection with on/off-switch instead of screw-terminal, exchanged a few electrolytics which measured below nominal capacitance) I took a look at the mosfets which are STW20NB50 with a continous Id of 20A @ 25°C. Should be OK ... or do those seem to be more than they are?
Anyway, I do not have this type of mosfet in my box, but I've got some which might fit, and which are 100% original.
So my first question, could I replace the STW20NB50 with IRFP460 or STW26NM60N?
My 2nd question, if the 1st one is a "yes": Never change a running system, or better be safe than sorry 😉 ?
best regards
Jochen
I've got an adjustable SMPS with max. 48V/ 10A, bought at Amazon, brand/ model is "HJS-480-0-48". I want to use it as power supply for a class-D amp in stereo BTL mode driving two 6.5" Midwoofers (atm. I've got 5.25" midwoofers driven by LM3886 chipamps which are really loud enough (max. 60%, never tried more) but I just want to move more air). I think, I'd never really torture the PSU, but I've read a (or maybe two) review(s) where this specific SMPS broke down when driven near the max. current.
As I made a few little modifications (bigger & slower fan, internal mains power connection with on/off-switch instead of screw-terminal, exchanged a few electrolytics which measured below nominal capacitance) I took a look at the mosfets which are STW20NB50 with a continous Id of 20A @ 25°C. Should be OK ... or do those seem to be more than they are?
Anyway, I do not have this type of mosfet in my box, but I've got some which might fit, and which are 100% original.
So my first question, could I replace the STW20NB50 with IRFP460 or STW26NM60N?
My 2nd question, if the 1st one is a "yes": Never change a running system, or better be safe than sorry 😉 ?
best regards
Jochen
Yes, never monkey with a mains SMPS, the design constraints are many and subtle, and single-component failures are all tested for safety certification. Change something and you lose certification / confidence that its fail-safe.
Assuming its safe in the first instance - isn't this an unbranded Chinese cheapo supply? Personally I'd not buy mains supplies from anything but a reputable electronics supplier, who knows what junk you might be getting otherwise (I've seen literally shocking examples).
Assuming its safe in the first instance - isn't this an unbranded Chinese cheapo supply? Personally I'd not buy mains supplies from anything but a reputable electronics supplier, who knows what junk you might be getting otherwise (I've seen literally shocking examples).
No still clueless person should buy a "not so expensive" (newspeak for cheap) SMPS from the famous Amazon brand (With Bezos electrolytic caps) and think he/she can improve that. Unless one is capable/experienced and has the right equipment of course. The question if the insurance company will pay for the damage after things went wrong still stands though.
As Mark says, it would have been a much wiser choice to buy from a reputable brand and just use it. One can then be assured the PSU has been tested for the required specifications and it will not transmit extreme EMI.
You may want Mercedes quality for a Fiat price, not a pimped up Renault for a Fiat price.
As Mark says, it would have been a much wiser choice to buy from a reputable brand and just use it. One can then be assured the PSU has been tested for the required specifications and it will not transmit extreme EMI.
You may want Mercedes quality for a Fiat price, not a pimped up Renault for a Fiat price.
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