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Old 24th March 2004, 01:57 PM   #1
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Default RECTIFIERLESS, is that possible?

HI

First, I`m only a technician and not an Engineer but it seem to be impossible to me...

I have find something on lowth-x website that picked up my curiosity.

on their amplifier line they claim to use rectifierless power supply.

FROM LOWTH-X SITE
"...The heart of the JI-300 is an innovative rectifierless power supply that provides high speed energy delivery on transients. Power supply impedance is fifty times lower than conventional rectifier/filter supplies..."

integral text is here
http://www.lothx.com/JI%20300.htm


How can they do that?
Any idea about their powersupply configuration. Are they use battery?


Thanks
Martin
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Old 24th March 2004, 02:37 PM   #2
hacknet is offline hacknet  Singapore
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yup. they are running off batteries...
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Old 24th March 2004, 06:24 PM   #3
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yup. they are running off batteries...
A 300B on batteries? Don't think so. It's probably some market speak as usual refering if anything to the absence of diodes.
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Old 24th March 2004, 06:48 PM   #4
dhaen is offline dhaen  Europe
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If I remember correctly, car radio's used to use a vibrator pack (caution ) .
It used a device like a fast switching relay, to switch DC into a step-up transformer.
Now, if you know the switching phase, which you would, then just 2 more sets of changeover contacts allows synchronous rectification without diodes.

I'm not saying they are using contacts, but some kind of synchronous switching may be possible.

Of course it could just be marketing lobbocks.
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Old 24th March 2004, 07:06 PM   #5
SY is offline SY  United States
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It's a solar cell. Or hydrogen power. Or maybe a Branley Coherer.
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Old 24th March 2004, 07:11 PM   #6
dhaen is offline dhaen  Europe
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Default I was being serious....

Now we're being rediculous
So how about Black Holes and Quantum Foam
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Old 24th March 2004, 07:19 PM   #7
SY is offline SY  United States
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Default Black Holes and Quantum Foam

Sounds like Taddy Porter.

Weren't vibrators used the opposite way, that is, to convert DC to AC? I remember those in old police radios that I used to convert to 2 meter band usage.
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Old 24th March 2004, 07:37 PM   #8
dhaen is offline dhaen  Europe
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Default Good vibrations

Indeed. But as I stated, before rectifiers were cheap, it was possible to rectifiy the AC using synchronous switching with changeover contacts.
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Old 24th March 2004, 07:47 PM   #9
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SCRs? Diac? Triac? Three phase AC? Manipulation of AC whereby a switch acts in conjunction with the AC to swap polarities, making for DC?

I guess the SCR would be out since it is a Silicon Controlled... Rectifier.

From the underside view, it sure looks like a switching power supply to me... from the best of my ability to see such a tiny picture. But it is reasonable to assume it is a type of digital switching supply. I think Sony (or someone!) made one back in the late 1980's where the AC was turned into a square wave, then the negative half was brought up to the positive half. This resulted in a virtual DC, where minimal filtering was needed for the actual power supply noise, and large capacitance used for reserve. Yes, it can be very low impedance, and like Carver's cube amp, be a "current on demand" circuit.

But... that's silly, because SE amps are at full current at idle! They actually draw less current with signal. I have done an experiment measuring B+ with and without signal, and found upwards of 4 volts more B+ with signal.

I wonder if they mean rectifierless in that there is no tube rectifier.

One can make a kind of rectifier by using two transistors in a flip flop circuit, if memory serves.

Hey SY,

No, vibrators were used to convert 6 or 12 volts DC to higher voltage DC. As I am sure you know, transformers only work with either AC or pulsing DC. The vibrator provided a pulsing DC to a step up transformer. I have a "farm" radio that uses one, and fixed a friend's old car radio that used one.

BTW, if they used a kind of electronic vibrator circuit, they would still have to convert AC to DC via rectifiers. That is just the way it is, even with switching power supplies.

My

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Old 24th March 2004, 07:48 PM   #10
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John

Synchronous rectification is what i also suspect but it may even be more prosaic. Curious though, would the switching and phase detection arrangement not introduce more noise?
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