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 300.htm
How can they do that?
Any idea about their powersupply configuration. Are they use battery?
Thanks
Martin
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 300.htm
How can they do that?
Any idea about their powersupply configuration. Are they use battery?
Thanks
Martin
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.
) . 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.
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
Gabe
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
Gabe
All I know is, if it has an AC cord, it HAS to have some sort of rectification, period, no bones about it, end of story!! Even if it used a generator (120VAC motor > 400VDC & 6.3V generator) it STILL has rectification because the very function of the commutator in the motor synchronously rectifies the winding voltage.
Some vibrators had DPDT contacts, providing synchronous rectification. Most probably used a 6X4 or something.
I vote for the same thing that causes every "high-quality" tube amp to be upwards of $10,000. Marketing bull****.
Tim
Some vibrators had DPDT contacts, providing synchronous rectification. Most probably used a 6X4 or something.
I vote for the same thing that causes every "high-quality" tube amp to be upwards of $10,000. Marketing bull****.
Tim
Just a nice pic of the inside (be patient):
http://www.lothx.com/mj4.jpg
It is stated somewhere else that is being rectified with ferriet choke resistors en caps ?!
http://www.lothx.com/mj4.jpg
It is stated somewhere else that is being rectified with ferriet choke resistors en caps ?!
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