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
A 300B on batteries? Don't think so. It's probably some market speak as usual refering if anything to the absence of diodes.
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.🙄
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.
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.
Good vibrations
Indeed. But as I stated, before rectifiers were cheap, it was possible to rectifiy the AC using synchronous switching with changeover contacts.
Indeed. But as I stated, before rectifiers were cheap, it was possible to rectifiy the AC using synchronous switching with changeover contacts.
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
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?
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?
analog_sa said:
Not with fast SS cicuitry. I believe John was referring to the old relay version, which was actually used since the early 1900's in cars where they used AC generators as opposed to our modern alternators. The relays would convert AC to DC.
Gabe
I know that professional audio Solid State amps have been using digital high frequency switchers for several years with great success, in fact most are moving in that direction. But how a 40kHz switcher would play with a tube amp is questionable.
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
Only $10,000?
How about one for $90,000!!!!!
Dick Sequerra makes one for that much. Holy Moly!
But now I digress.
Gabe
How about one for $90,000!!!!!
Dick Sequerra makes one for that much. Holy Moly!
But now I digress.
Gabe
imix500 said:
Switchers have been used in some tube amps and preamps with excellent reputations, even going back to the '70s. Audionics and Berning are two that come to mind. I've still got a well-modified TF-10 with a 40kHz switcher- all discrete, yet.
Yes, it is indeed a battery powered - thirty-something 12 volt batteries in series. It's made in Korea and it costs more to ship the power supply from there than the batteries cost. Beautifully made stuff although it's only a simple WE91-type circuit.
John
My guess is marketing speak for switch mode power supply.
Think computer power supply, with a 6.3V and 350V capability.
Transformers are generally better, as they aren't as noisy.
Think computer power supply, with a 6.3V and 350V capability.
Transformers are generally better, as they aren't as noisy.
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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