Choke power supply- part 2

And Pass amps use choke filters in their supplies too, but the question was why they are not more common, not whether they "can" work. I don’t need Mike Moffat and Jason Stoddard’s blessing for my comment and I expect across a table with engineers, their answer would not be much different from mine.

The fact it "impresses" you means it already "works", even if it does not make sense. It sounds really cool from a marketing standpoint. Choke regulation used to be common in linear power supplies.

@oldears , you not understanding my responses does not make them inane.

What I said was:

Whether you put the choke on the input or the output the effect is the same. A transformer reflects the impedance from one side to the other based on the turns ratio

I did not say:

It is inconceivable that someone would state that it makes no difference as to whether a choke is used before or after rectification.

While the values are the same, the net effect w.r.t. choke regulation is the same. If you don’t believe me, work out a small signal model or simulate it. I assume you understand reflected impedance? To your point, when people talk about a choke regulated power supply, they usually mean larger inductors, than the typical minimum used for higher frequency harmonics of the AC line and noise. The transformer has enough bandwidth in this case to put a regulation choke on either side.

Your last post did not say anything I did not say already, I just put in more detail:

Output of a bridge rectifier is DC + harmonics of twice the AC frequency. The choke in combination with the capacitor forms a filter eliminating some of those harmonics, but the choke in combination with the load does as well. Hence, the output voltage can droop. So much for your high dollar, low resistance AC power cord.

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The schematics above are 6 types of ways to do choke regulation. The big inductor after the bridge has wicked overshoot but eventually settles. Normally you put an element across the inductor. Note all the voltages are less than the capacitor alone. That is the load dependency issue with choke supplies. The one that overshoots a little and then settles fast with little ripple is a hybrid of inductance before the transformer and after the bridge. Hybrid approaches are best.

Sorry it is hard to read. Not the easiest editor with embedded images.

The question was why are there not more amps with choke regulated supplies. Not whether you can make one work. I certainly did not question whether you could. I said there is little practical reason for doing it (beyond what I stated) and many practical reasons for not doing it.

Marketing is not just advertising, it is also how you present your products to market. Absolutely Schitt does marketing, they don't do a lot of advertising.

@daveyf ,

The first question would be do you know what a choke power supply is?

More accurately would be a choke filtered power supply, with a few different variants.

Why not?  Other than the cost and bulk, there is the question of whether they are the best implementation.

That said, most linear power supplies have some choke filtering, just for high frequencies.

Output of a bridge rectifier is DC + harmonics of twice the AC frequency. The choke in combination with the capacitor forms filter eliminating some of those harmonics, but the choke in combination with the load does as well. Hence, the output voltage can droop. So much for your high dollar, low resistance AC power cord.

To get enough inductance to be useful, you need a large inductance which means materials that are not great at high frequency. So at that point, do I really want the big inductor, or should I go for s smaller inductor and burn off a bit of power with a linear regulator? The best answer is always trade off the properties for the best overall implementation.

Whether you put the choke on the input or the output the effect is the same. A transformer reflects the impedance from one side to the other based on the turns ratio. Even if the inductor is on the front AC side, it still effectively forms an LC with the capacitor. Note Schiit's Description. It works, but is it is a good engineering idea? Questionable.  The "custom nickel core" sounds all impressive, but that is just common core material and custom inductor is not remotely difficult.

And pure LC—inductor-capacitor filtering from the highest to the lowest band, including 4 custom 80% nickel-core inductors as big as 1.5 Henries.