Active bridges - what next?

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It will handle even more with a small heatsink.
Searching for the right mosfet took me almost 5 months.
For the time been you may subscribe to GB.

This bridge have a strong sonic signature, improving dynamics and midbass response.
It is by far better than any Schottky i have tested.

Regards,
Tibi
 
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It will handle even more with a small heatsink.
Searching for the right mosfet took me almost 5 months.
For the time been you may subscribe to GB.

This bridge have a strong sonic signature, improving dynamics and midbass response.
It is by far better than any Schottky i have tested.

Regards,
Tibi

Which MOSFET did you end up using? If you want to PM me that is fine.
 
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The problem with linear supplies is they just take power from peak of mains and electric supply companies don't like that.

Nigel, you are once more right. But, for the little power needed and with the inductance inside the building and to the building, mixed up with the rest of the consumers, such poor load characteristics can hardly be seen at least on the other side of your neighborhood power distribution box. I believe that for home-audio we can go on with transformers and traditional rectification.

In case of continued concerns, the transformer may be replaced with a power factor corrected SMPS having only a coarse output to be followed by a linear regulator. Linear regulators still provide the best regulation performance as I am aware but their qualities may not always be needed.
 
FauxFrench, you are right that linear PSU charging currents of a single device will be lost in the other domestic loading but it can cause a problem when done on an industrial scale:

I had occasion to run into this problem at a broadcast company. Some of our broadcast kit was showing symptoms of low mains but an AC voltmeter showed it to be within spec.
A scope on the mains immediately showed the problem - the top of each cycle was flattened.
I had a suspicion about one of our neighbours in the building basement. On visiting them they proudly showed me 1000 VHS and Betamax VCRs duplicating tapes! All with linear power supplies.
Fortunately they were only affecting one of the phases badly, and with some load reorganisation the problem was solved.

This was before most kit had SMPS and true-RMS meters were common.
 
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Here's what the mains waveform looks like at my house. As far as I'm concerned, the flat top is beneficial because it increases the conduction angle of rectifier diodes in linear power supplies.

PS Audio's "Mains Power Regenerator" products seem to agree; sales blurb from their website attached below.

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FauxFrench, you are right that linear PSU charging currents of a single device will be lost in the other domestic loading but it can cause a problem when done on an industrial scale:


I had occasion to run into this problem at a broadcast company. Some of our broadcast kit was showing symptoms of low mains but an AC voltmeter showed it to be within spec.
A scope on the mains immediately showed the problem - the top of each cycle was flattened.
I had a suspicion about one of our neighbours in the building basement. On visiting them they proudly showed me 1000 VHS and Betamax VCRs duplicating tapes! All with linear power supplies.
Fortunately they were only affecting one of the phases badly, and with some load reorganisation the problem was solved.

This was before most kit had SMPS and true-RMS meters were common.


This was a particularly inconsiderate copying business for the neighbors.
When they in the past had to decide for AC or DC power distribution nets, the trade-off was conveniences like the possibility to use magnetic transformers, the durability of mechanical power switches, facility of generators, safety etc. For a start, the consumers they had in mind were incandescent lamps followed by heating. Both rather Ohmic loads. Today, far more complex loads are used on the net and perhaps the decision would have been different had they been able to foresee that.
It is evidently easiest to take the electrical power during the moments when the energy is at a maximum with the highest voltage. But, then we end up with a power factor issue that is a problem for efficiency of the distribution net. Passive power factor correction circuits were bulky. Today with cheap electronic means PFC is possible even for smaller consumers. For long (normal) audio equipment will make no significant contribution.
I live in a rural area with little industry and no particularly delicate consumers. Living in an area with metallurgical industry should be a nightmare.
 
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If many are taking a bite out of the peak, is there more or less left for everyone else?


This is the kind of question pupils would fear in an exam because it appears to have the nature of a trick-question. Luckily I am over that period in my life so I will give it a go:
The producers make a certain amount of energy available on the net and the consumers each take a part of that energy according to their needs. The less the voltage, the more difficult it is to use the energy available but as such that remaining energy is the same whether they take bites out of the peaks or more equally distributed. However, the worse the power factor the less efficient becomes the distribution net. So, as such all consumers loose from many taking bites out of the peaks.
Flunked?
 
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