Wednesday, 22nd October 2014.

Posted on Sunday, 28th November 2010 by Auw Jimmy

Today, I drill some acrylic and heatsink to mount the regulator PCB. What a tiring drilling job! Not too easy to drill a lot of holes on the heatsink, though (not included the wrong holes one!).

Finally, the PCB could be mounted beautifully. The pass transistor mounted on the separate heatsink on the bottom. I just need to wire them to the PCB, add the main transformer, then we can evaluate its performance.

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Posted on Saturday, 27th November 2010 by Auw Jimmy

When it comes to high current and high efficiency, actually we don’t have much option rather than using switching based power supply. For most of consumer electronic equipment, this kind of power supply probably one of the best choice. But for audio, I would like to avoid it – really avoid it.

But again, the option to go high current with non-switching based power supply probably would introduce another issue – heat or thermal dissipation. We are talking a high current regulated output. Bear in mind that switching based power supply is quite stable. So if we plan to replace them, make sure we have a quite stable solution also. Not much choices available, rather than go to the regulated one.

Not many regulator could handle high current. Quite easy to go up to 1A with classic 78xx/79xx based regulator – although the sonic performance is mediocre.

Better solution we can pick LM317 probably up to 1.5A or the bigger brother, LM338 up to 5A. This one is sonically better than 78xx/79xx based regulator.

Another high-end approach is to use LT1083/84/85/86. This one could handle up to 7.5A with some limitation. Probably one of the best, but I doubt we can push the limit for this kind of regulator.

I would try another cheaper solution, LM723 with extra pass transistor to provide enough extra current (we can go up to 10A with this, and the heat will be well shared to the pass transistor rather than on single chip).

Actually we can go with 0.5 Watt of resistor, but I go with the 2 Watts for all when available.

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