I posted an example above, where I use anode B+ to load error amp transistor. No problems with voltages, when you have more than filament power supply.
Plenty of MOSFETs are available that would work on such voltages and currents. Look for 60V or 100V rated power MOSFETs, they have huge transconductance. Shottky diodes can be used dual like in computer power supplies. Select one that has lower voltage drop on current. Zener should be selected from 5.6V nominal, to get 6.3V on output +/- 5%, since 5.6 + 0.6V B-E junction would result in 6.2V. Zeners have own tolerance, so better select one for your regulator.
297 matches on Mouser website:
Si Through Hole N-Channel 60 V MOSFET MOSFET | Mouser
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Sorry, but I am very slow, must see an equation and cannot think in terms of "rate of change" nor "magnetic flux" either, maybe it is a magnetic flux density?
From post#83 the induced voltage is
Uac = (S/c) dB/dt
Which in turn shows that the time varying voltage is the source of the time varying magnetic field B, naturally, to obtain the ubiquitous expression for B, one must integrate this differential equation.
And that explains the use of an integrator in the experimental jig, so it yields, more or less, the magnetic field B.
A long ago I saw a much better experimental layout, but I could not find it again, and the link was the least ugly at hand.
Well, not really, physicists here are very punctilious and always present the fields different as they are, even more, mathematicians also show other difference, such as vector and pseudo-vector...
Lol. Yes, but I must admit that is for fear, fear to deal with a magnetic permeability which is not a constant, but a tensor.
That's why since a time ago I just design SE transformers.
I posted an example above, where I use anode B+ to load error amp transistor. No problems with voltages, when you have more than filament power supply.
Hi Anatoliy! Good to see you around here!
Yes, I did see it, thanks; hope you don't mind if I take some ideas...
Пока!
Feel free! I would be glad! I like when designers learn thinking from all around the box. ;-)
Buena suerte!
Do not worry, most of my friends are worse than your spell checker, I know at least 6 wrongs for my nickname.
Большое спасибо!
Two things can create an electric field:Hearinspace said:
1. charge
2. a changing magnetic field
The 'shape' of the electric fields are different: charge creates a diverging electric field, while a changing magnetic field creates a curling electric field.
I really don't see how this thread has gone from AC vs. DC for heaters to a discussion of EM fundamentals.
I love how even the most basic question of how people prefer to power their filaments has turned into a flaming dumpster fire of semantics, physics, and electromagnetism.
Never change, DIYaudio, never change
If you guys need me, I'll be sitting at my kitchen table and pre-twisting solid-core filament wire with a cordless drill.
Never change, DIYaudio, never change
If you guys need me, I'll be sitting at my kitchen table and pre-twisting solid-core filament wire with a cordless drill.
Thank you, Zeners & resistors both 1/4W? Wich one MOSFET?
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As this is a technical forum, both AC and DC heaters implementation need some fundamentals, some people just do not want to make something which do not understand, and those fundamentals belong to physics.
Other forums over there just do not have renowned physicists like you to discuss this kind of things, so I do not see it *that* bad.
I think what's trying to be said is that the fundamentals, while important, aren't really relevant to the topic. It doesn't matter if you can calculate the magnetic flux coming from a wire or not when you are building or even designing an amplifier it only matters that you know how to deal with the problems it can cause. No amount of equations tell you to run twisted pairs of AC line along the chassis edge with straight lines to the tubes or to run pre-amp tubes at the end of the line to reduce AC current at the sensitive pre-amp tube's pins.
It's the classic engineer vs tech scenario.
It's the classic engineer vs tech scenario.
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If you cannot calculate the magnetic field produced by a cable, or you just ignore the fundamentals phenomenologically, you do not know how to deal with the problems it can cause. IMHO.
There are equations, though a bit complicated, that tell you how to run a twisted pair for AC line, if you do not know them it is another story.
Some people like to design amplifiers based on calculations.
Some people like to design amplifiers through trial and error.
And some people just can copy other designs and build amplifiers with given recipes.
At the end, amplifier design is a matter of taste, like the use of AC or DC.
DC is a necessity with the 'I can hear noise' crowd in DHT vs transistor amps.
And in phono stages... HIFI moving coil carts exist since 1948 when the 33 1/3 appeared in the market. DC heater appears only 20 years later at least!
One important fact to remember is that your transformer with 1A 6.3V is designed for AC heaters. If you power to DC you need a 2A 6.3V ... this is a MAJOR problem with DC heaters done correctly.
And in phono stages... HIFI moving coil carts exist since 1948 when the 33 1/3 appeared in the market. DC heater appears only 20 years later at least!
One important fact to remember is that your transformer with 1A 6.3V is designed for AC heaters. If you power to DC you need a 2A 6.3V ... this is a MAJOR problem with DC heaters done correctly.
What about the "I love the warmer sound of intermodulation" crowd?
I think that today MC cartridges are way better, most components available today to make a really good DC heater supply are way better too.
The design of an amplifier ends on the design of its power transformer, I do not see the problem.
If wasting about 12W is a drama for you, why don't go on class D SS amplifiers?
Just in case, this is the wrong forum BTW.
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If losing about 12W is a drama for you, why do not go on class D SS amplifiers? Just in case, this is the wrong forum BTW.
I think he meant that most people fail to understand that rectified DC "costs" more in terms of how many VA the PT needs to be. They overload it _SEVERELY_ but don't need a dropping resistor... They have hum on DC and say "what's the difference?".
I could be wrong.
You can calculate power multiplying voltage by current.
All 4 MOSFETs, obviously, can be used.
When people don't understand science, but believe in it instead, they believe in myths that sound pseudo-scientifically. You have a passion Popilin to educate them. Respect.
Hi Anatoliy, thanks for your kind words.
I learned a lot here on the forum, especially from wise people like you, my intention is simply to give back something of what I learned here.
Пока!
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