The Chinese offer a Class D amplifier in conjunction with a power source SMPS - IcePower.
The question of the possibility of amplification of direct current needs to be clarified.
ICEpower125ASX2 - 道客巴巴
The question of the possibility of amplification of direct current needs to be clarified.
ICEpower125ASX2 - 道客巴巴
An amplifier of 10-20 watts is easy to perform on a chip for car amplifiers with a bridge connection of the output stage.
Схемы автомобильных усилителей на TDA8561Q - Mariolla
Схемы автомобильных усилителей на TDA8561Q - Mariolla
Quote-"in order to generate a closed magnetic field " .
Are we then talking about a --ELF generator ?
If so quite a while ago a gentleman named Bruce Forrester of Dayton Ohio built one and was independently tested at 7.83 Hz .
NASA used to sell VLF radio kits for kids -website taken down not much later .
The aerial was the same method used as patented in the 1930,s the---ground .
This from "a scientist " -
In order to build an ELF generator, the transmitter array has to be a certain percentage of the length of the wave you want to generate. Since the waves you want to generate are very long, the transmitter has to be fairly big. Which means expensive. And hard to do without attracting attention. In order to generate ELF waves of any amplitude, you're going to need a LOT of power. In the kilowatt- to megawatt range. Which is hard to do without attracting attention. Simply researching the technology required to generate extremely low frequency EM radiation is likely to attract attention. It's not something that a lot of people should be fooling around with, IMO.
Okay you are not building a transmitter per se but actually generating ELF in any significant power range is not easy or cheap.
Are we then talking about a --ELF generator ?
If so quite a while ago a gentleman named Bruce Forrester of Dayton Ohio built one and was independently tested at 7.83 Hz .
NASA used to sell VLF radio kits for kids -website taken down not much later .
The aerial was the same method used as patented in the 1930,s the---ground .
This from "a scientist " -
In order to build an ELF generator, the transmitter array has to be a certain percentage of the length of the wave you want to generate. Since the waves you want to generate are very long, the transmitter has to be fairly big. Which means expensive. And hard to do without attracting attention. In order to generate ELF waves of any amplitude, you're going to need a LOT of power. In the kilowatt- to megawatt range. Which is hard to do without attracting attention. Simply researching the technology required to generate extremely low frequency EM radiation is likely to attract attention. It's not something that a lot of people should be fooling around with, IMO.
Okay you are not building a transmitter per se but actually generating ELF in any significant power range is not easy or cheap.
I would start with a budget Class "D" pro amplifier (make that semi-pro) and mod the input stage coupling capacitor.
Hi
Low-frequency amplification is about the easiest thing for any solid-state amp to do. That is where feedback has the most control since there is maximum gain to throw away.
DC coupling at the ouptut is a must, as others stated, so you do not need a massive coupling cap. A DC servo will keep DC out of your coil - which you need to do just the same as if it were a speaker.
You have to know the nominal impedance to be able to design or choose the correct amplifier. At 8R, 100Wrms requires aswing of 127V peak at almost 16A peak. The best way to drive this is using a bridged pair of amps as this allows the supply rails to be <90V and the filtering and semis are inexpensive.
if your coil is 2R, then 1000Wrms is 45V peak at 23A peak. This is easily done with single-ended drive of the coil and rails of <60V.
In either of the above, you need to manage heat on the order of 250Wrms.
Of you went class-G or H then you could cut the waste heat enormously, especially if you used a 4-tier supply, in which case heat would be cut to a quarter, so 60W or so.
Low-frequency amplification is about the easiest thing for any solid-state amp to do. That is where feedback has the most control since there is maximum gain to throw away.
DC coupling at the ouptut is a must, as others stated, so you do not need a massive coupling cap. A DC servo will keep DC out of your coil - which you need to do just the same as if it were a speaker.
You have to know the nominal impedance to be able to design or choose the correct amplifier. At 8R, 100Wrms requires aswing of 127V peak at almost 16A peak. The best way to drive this is using a bridged pair of amps as this allows the supply rails to be <90V and the filtering and semis are inexpensive.
if your coil is 2R, then 1000Wrms is 45V peak at 23A peak. This is easily done with single-ended drive of the coil and rails of <60V.
In either of the above, you need to manage heat on the order of 250Wrms.
Of you went class-G or H then you could cut the waste heat enormously, especially if you used a 4-tier supply, in which case heat would be cut to a quarter, so 60W or so.
HI, thanks for your precious suggestions
By the way following your suggestion about the TDA7293 searching on the net I found this: TDA7293 parallel amplifier board, 600W power amplifier board( high power mono AMP board )|power amplifier board|amplifier boardmono amp board - AliExpress
it is very inexpensive, and maybe with some modifications do you think that it could do the work?
All this, of course, is pure theory, and I don't know what results I will get, but it is still an interesting game to play 🙂
Never thought to get 500w from +-12V, I was thinking at the second amplifier, the one about 10-20W.
By the way following your suggestion about the TDA7293 searching on the net I found this: TDA7293 parallel amplifier board, 600W power amplifier board( high power mono AMP board )|power amplifier board|amplifier boardmono amp board - AliExpress
it is very inexpensive, and maybe with some modifications do you think that it could do the work?
Since I will wind the coil I thought to go for 4 ohms pure resistance, I know that rising the frequency the impedance will go very high, for that reason I would like to start with a strong power amplifier. Anyway, I also tried with a bifilar coil, with opposing winding that has the result of self-canceling the magnetic field and entering in the domain of scalar waves (Tesla studies).
All this, of course, is pure theory, and I don't know what results I will get, but it is still an interesting game to play 🙂
The 10-20W amplifier running from +/-12V is trivial. A DC-coupled TDA7377 (BTL) amplifier or similar used for a car will do the job.
Project management is about identifying as early as possible the elements that may cause problems.
The TDA7293 board with seven (!) ICs in parallel is very close to what you need. My guess is that if you bypass the input coupling capacitor (the big red thing next to the input signal terminals) you have an amplifier that can run down to DC. You will need two such boards running in counter-phase (BTL) in order to get the power you want. With a +/-40V power supply, you can get close to 700W in 4 Ohm. You will need 1 or 2 large cooling profile(s) and a fan for each profile. A slight hiss from the fans will hardly bother your experiment. 4 Ohm resistance is fine.
Now to the most costly - a symmetrical power supply with a voltage around +/-40-42V (regulated!) and a power around 1200W-1500W!
For the physics experiment, you are the expert and perhaps also some other members on this forum. I am just a simple engineer. But recalling the fear of creation of a "black hole" when they were about to start the CERN particle accellerator - DO NOT MAKE a BLACK HOLE! (whatever you try). Neither I, nor your family will appreciate that! We have just been released from Corona-confinement and we do not want to bother with black holes so soon after. 😀😀
Thanks, I didn't know the possibility to connect two of such boards in BTL, this is interesting given the fact, that since not knowing what power I would need, I said myself better safe than sorry, so I thought big, but knowing that I can possibly increase the power only by adding one more board I can start with one and see what happens.
And don't worry... no particle collisions, black holes nor interstellar travels...😀😀 all this has the purpose of healing (I hope), based on the principle of frequency information
I did notice that those ELF signals have a medical connection .
Funny ---- one use healing other use killing its a funny world.
Funny ---- one use healing other use killing its a funny world.
If you use only one board and a +/-40V power supply, you will have around 25% of the power you would have with two boards. My estimate is 180W in 4 Ohm with one board. Perhaps it is enough for your experiments.
You're absolutely right ... We in Italy use to say that every medal has its reverse. Unfortunately, we live in a world where everything related to health that does not fall within the official canons is banned, including google that is slowly censoring all the information regarding healing with alternative methods. I have successfully experimented with various magnetotherapies, both in low and high frequency, as well as various techniques that include treatments with frequencies. As you say it is (not so) funny world.
Since I am always willing to learn, and I consider myself a newbie with regards to amplifiers, (I've always been more in automation), I have never been able to understand how watts work in this environment. (Sorry I know that for you I am cursing).
I know there are peak watts, musical and rms, and that's ok, and that the Chinese commercially pump a lot. Of course, I didn't think to get 600W from 7 TDA in parallel, but I thought at least half since the datasheet reports 80W continuous on 4 ohms with a +-40V power supply, but 180? And why 4 times more with two boards?
Thats one reason I don't have Google on my PC Oxyjo , I use DDG (Duck-Duck -Go ) and a European (German ) search engine ,no problem picking up your subject on them.
Its not so unusual babies go to sleep when rocked due to being in the womb before birth and the mother moving around +their mother,s heartbeat.
Psychologists use hypnotism to find your childhood related problem that entails SLOW defined words spoken softly to you, sorry to say I cant be hypnotized.
I have plenty of sympathy for those bucking the system it would be a dull world if we were all the same.
Its not so unusual babies go to sleep when rocked due to being in the womb before birth and the mother moving around +their mother,s heartbeat.
Psychologists use hypnotism to find your childhood related problem that entails SLOW defined words spoken softly to you, sorry to say I cant be hypnotized.
I have plenty of sympathy for those bucking the system it would be a dull world if we were all the same.
The traditional way to operate a load is "SE-configuration" where one end of the load is connected to "ground" and the other end of the load is pulled above and below ground level in a symmetrical manner. The limits (peak) for the load-voltage are the rail voltages. With +/-40V rail voltages, the load voltage can be maximum +40V and minimum -40V (these are peak voltages). The maximum power (at clipping of the sine-wave) in 4 Ohm with +/-40V rail voltages and SE-configuration can be calculated to (40Vx40V)/(2x4Ohm)=200W. In practice we end up a bit lower power because a class AB amplifier cannot pull the load voltage fully to the rail voltages but leave a 2-5V drop depending on the current.
With BTL-configuration you " pull" in both ends of the load simultaneously but in counter-phase and typically with the same amplitude. That means the peak voltage on the load (not taking account of the voltage drop) can be from one rail voltage and to the other rail voltage. With rail voltages of +/-40V, the rail-to-rail voltage is 80V, thus, the double of what it was for the SE-configuration. As the voltage is the double also the current is the double as long as the load impedance remains the same. For BTL-configuration, with +/-40V rail voltages and a 4 Ohm load, the theoretical maximum power (sine-wave clipping level) can be calculated to (80Vx80V)/(2x4Ohm)=800W. Hence, 4 times as much as for SE-configuration because both voltage AND current become the double with BTL-configuration if the load impedance remains the same (4 Ohm).
Why does the datasheet state 80W in 4 Ohm with +/-40V supply? Because a TDA7293 chip can handle a maximum peak current of 6.5A. 6.5A peak means 4.6A RMS. At the maximum current in a TDA7293 chip, the power in 4 Ohm is (4.6Arms x 4.6Arms) x 4Ohm = 84W (no voltage drop taken into account).
The 80W limit is because the current limit of a single TDA7293 chip is reached, not because we have voltage clipping.
The amplifier board you propose has seven TDA7293 chips connected in parallel and can handle in the order of 45A (peak). With that board there will be no current limitation in reality and we can take the output level to the voltage clipping level which I assume to be +/-38V (2V drop). Then I arrive at a maximum output power (voltage clipping, not current limit) of (38Vx38V)/(2x4Ohm)=180W.
Mystery solved.