I needed a 15V power supply to replace a dead one. And something at least 2.5A.
But there are two issues:
- 15V power supplies of >2.5A are significantly more expensive than the more common 19V (at the time of my searching)
- Always expect worst-case scenario when not proven otherwise - the DC quality of these power supplies are crap. And when I say crap, it is more crap than a typical desktop computer power supply. Much more crap.
Hence the idea of using a linear regulator + filter to clean up the circuit and drop the voltage at the same time came up.
Thanks to a group of helpful and knowledgeable enthusiasts over at diyAudio forums a good design was created very quickly. I implemented one of the earlier designs but the topic has progressed even further.
I will not post the design I used out of respect for the community by keeping the internet free of bad circuits when superior ones exist, but basically the idea I used was capacitor multiplier with one RC stage at the base of the darlington, fed to a LM338 linear regulator.
I so need a camera. PC Show coming soon.
Missing input connector and output strain relief. Grommet I got was too small.
P2p build, active devices bolted to the tin case which doubles as a heatsink.
I'm getting 38°C with no load and 46°C with load for the LM338, and 34°C no load 38°C load for the transistor, taken directly from metal part of the TO-220 packaging. Same 29°C air temperature. Compare it with the 47/54 heatsink temp with the Zhaolu power supply.
I don't know if this or having the cover closed, and the surface with the components bolted-on flipped over to face the top would provide better cooling, but for certain, at these temperatures and power draw, it would not matter.
W A R N I N G !
W A R N I N G !
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