I would suggest that winding an inverter transformer will be about 100x easier than winding EIs for output and coupling. It's a maximum of 50-60 turns on a Ferrite toroidal core, whereas the other requires a core at least equal to power rating (ever seen a 200VA core? It's massive!!), and correct wire gauges on both ends. I'd estimate you'd need at least a few hundred turns on the primary to hit your current and resistance goals, and two to three times that on the secondary.
If you want a reverse connected mains transformer you cannot use single ended mode as the primary DCR is too low for most any amp to drive. Maybe a 1 ohm capable amp, and then that becomes expensive. A 50V center-tapped transformer, very common in the country, can be used in a push-pull output stage but you will get no bandwidth out of it. I doubt even speech is possible with such a design. I have used mains toroidals to do the job for a tube amp, and maybe a specially would unit will work (I do know that there are manufacturers who will wind just one). However toroidals have a DC balance issue and that requires other circuitry to overcome unless you have perfectly matched output transistors.
The reason that Ahuja could make those things work is because they used to have the transformers wound for them. Without that resource, you cannot move forward on the plan to clone their amps at a reasonable cost. Your admiration for them is because of a captive resource that is no longer available, therefore you have to change your direction.
As I see it you have two options.
1. Ahuja still exists and they may have spares for their old amps. It is possible that the output transformers may be available - though they will probably ask you how you managed to damage one. OTOH, they may not ask you anything. It is then a matter of picking out a model you like, sourcing the schematic, and reconstructing it or cloning it.
2. Move to a two-battery system, with a single 24V supply and run two amplifiers in bridged mode. This should net you about 30V voltage swing across the load, or around 50 watts into 16 ohms. I suspect this is your best shot if you want to avoid complications, and there are many designs that will do this kind of a job. The problem with a single 12V battery is the maximum voltage, a bridged amplifier can do about 20V if it very well-designed. That should still net you around 25 watts, which is deafening loud with a horn driver. Up North they use these systems in the 'Jugaad': Jugaad - Wikipedia, the free encyclopedia, and those things can be heard for miles.
If you want a reverse connected mains transformer you cannot use single ended mode as the primary DCR is too low for most any amp to drive. Maybe a 1 ohm capable amp, and then that becomes expensive. A 50V center-tapped transformer, very common in the country, can be used in a push-pull output stage but you will get no bandwidth out of it. I doubt even speech is possible with such a design. I have used mains toroidals to do the job for a tube amp, and maybe a specially would unit will work (I do know that there are manufacturers who will wind just one). However toroidals have a DC balance issue and that requires other circuitry to overcome unless you have perfectly matched output transistors.
The reason that Ahuja could make those things work is because they used to have the transformers wound for them. Without that resource, you cannot move forward on the plan to clone their amps at a reasonable cost. Your admiration for them is because of a captive resource that is no longer available, therefore you have to change your direction.
As I see it you have two options.
1. Ahuja still exists and they may have spares for their old amps. It is possible that the output transformers may be available - though they will probably ask you how you managed to damage one. OTOH, they may not ask you anything. It is then a matter of picking out a model you like, sourcing the schematic, and reconstructing it or cloning it.
2. Move to a two-battery system, with a single 24V supply and run two amplifiers in bridged mode. This should net you about 30V voltage swing across the load, or around 50 watts into 16 ohms. I suspect this is your best shot if you want to avoid complications, and there are many designs that will do this kind of a job. The problem with a single 12V battery is the maximum voltage, a bridged amplifier can do about 20V if it very well-designed. That should still net you around 25 watts, which is deafening loud with a horn driver. Up North they use these systems in the 'Jugaad': Jugaad - Wikipedia, the free encyclopedia, and those things can be heard for miles.
Please calculate it for me for an amp working in bridge mode on 12Vdc supply driving 1 ohm load. how much will be the power O/p.
thanks
Sudhir.
12Vdc allows an absolute maximum of 4Vac to your load.
This reduces as load impedance drops.
expect 3.8Vac into 8r0
maybe 3.5Vac into 4r0
By the time you are down to a 1r0 load expect somewhere around 2.5Vac to 3.5Vac depending on how you build it.
3Vac into 1r0 is 9W
A bridged pair of these 1ohm capable amplifiers will put out 18W into 2ohms.
You are ******* against the wind.
This reduces as load impedance drops.
expect 3.8Vac into 8r0
maybe 3.5Vac into 4r0
By the time you are down to a 1r0 load expect somewhere around 2.5Vac to 3.5Vac depending on how you build it.
3Vac into 1r0 is 9W
A bridged pair of these 1ohm capable amplifiers will put out 18W into 2ohms.
You are ******* against the wind.
Thanks for your valuable suggestions.
First I will try to get a trafo from some old amp. Once in somewhere 2001-02 I inquired about the o/p trafo of their BR-250 model , they quoted Rs.5000 thousand for that,thus I think that there is verey few chances that I would be able to clone theirs amps.
your second suggestions seems positive for me. But i would like to do it in a different way. I will take a bridge amp working on 12 volt supply and able to drive a load of 1 ohms (surely) and add an impedance matching transformer to drive 16 ohm load, but you have to suggest me a amp which can drive 1 ohm load on 12 volt.
Forget to mention , In my village I have the same type of audio system in my tractor , credit goes to my tractor driver. He sourced it locally with a horn type of speaker. The usb audio player has old LA4440 amp inside and It sounds quite loud but no comparison with big horns.
thanks again
sudhir.
Can I get some optimistic figures if amp is capable of providing proper or correctly saying; high current to drive 1 ohm load so there is less voltage drop.(forgive me for a bit confusing question as I have limited knowledge of working of amplifier).
thanks
sudhir.
It appears you are looking at driving a 1ohm effective impedance at the transformer input.
That means you need to build TWO amplifiers each capable of driving an effective load impedance of half an ohm.
Now your trying to pee into a tsunami.
That means you need to build TWO amplifiers each capable of driving an effective load impedance of half an ohm.
Now your trying to pee into a tsunami.
I think you need to listen to some advice, specially from Andrew. What you are attempting to do is quite the task for even an experienced designer and if you expect to be handed a design which you can build - one that has been tested, is reliable, meets your goals and is able to properly provide a linear signal, I don't think you are going to get one because this is not possible.
In your plan for example, how big is the transformer core? How many windings? Ten, a hundred, thousand? You can reach 1:4 turns ratio in all of them. Not possible to drive a single ended load of low output impedance with high current output into an impedance matching transformer either, that you will figure when you get to it.
Car amp will be loud enough, for more volume add more horns in parallel.
Good luck with your chosen path.
In your plan for example, how big is the transformer core? How many windings? Ten, a hundred, thousand? You can reach 1:4 turns ratio in all of them. Not possible to drive a single ended load of low output impedance with high current output into an impedance matching transformer either, that you will figure when you get to it.
Car amp will be loud enough, for more volume add more horns in parallel.
Good luck with your chosen path.
buy 110V modified sinewave inventer thats around 300W... then build single supply amplifier that runs off ~150V and there you go.. Tons of filtering has to be dont too..
Going to be expensive so you should buy a crappy car amplifier.
Going to be expensive so you should buy a crappy car amplifier.
Sir, your question is not stupid. but you are not aproaching from the proper angle. trafos dont increase power. what actually is the problem? all we have is 12V which should produce 200W across 8ohm. which is not possible if we go straight. to achive this, there are two options. either decrease load resistance or increase voltage. this is what exactly being done in trafo coupled outputs. we offer a very low impedance trafo primary to the 12V source. heavy current flows and enough power is produced. then we match this power to the 8ohm load using the trafo secondary.
Doesn't want to pay $300 for a specially wound audio grade transformer. I wouldn't either. Which is why I would use a standard mains trafo of sufficient size and turns ratio. They don't just suddenly quit working above 60 Hz - bandwidth may be better than you think. And since speaker impedance goes up with frequency in the mid range a little leakage reactance isn't the end of the world. A driver trafo could be replaced by a couple of op amps. If you had an 18-0-18 300VA and a couple of 2N3771's or IRFP064's on hand it could be tried out rather easily.
It's Ohm's law. The transformer you want is a step up transformer. That is how my old Motorola booster could deliver decent power into an 8 ohm load from a 12 volt supply. That is why car speakers are almost universally 4 ohms.
I've taken apart some OEM car "subwoofer" amplifier/speaker units. They sometimes contain oddball "woofers" with unconventional impedances like 1.2 ohms. This allows them to provide a decent amount of power with a cheap bridged digital amplifier. No high voltages are required.
A 16 ohm load requires higher voltage to produce power. A transformer is a logical way to make this happen for your application. Try what you have laying around.
"Please calculate it for me for an amp working in bridge mode on 12Vdc supply driving 1 ohm load."
A\D\S made some car stereo amps that were quite nice, 20W/4Ω and 35W/2Ω. They used a CFP output stage and could thus swing rail-to-rail (about 9V RMS from a nominal 13.8V auto supply). I would imagine that if you doubled the number of outputs it would drive around 60W/1Ω.
They used a pair of 2N6488/6491 per half of the bridge per each channel.
http://www.onsemi.com/pub_link/Collateral/2N6487-D.PDF
A\D\S made some car stereo amps that were quite nice, 20W/4Ω and 35W/2Ω. They used a CFP output stage and could thus swing rail-to-rail (about 9V RMS from a nominal 13.8V auto supply). I would imagine that if you doubled the number of outputs it would drive around 60W/1Ω.
They used a pair of 2N6488/6491 per half of the bridge per each channel.
http://www.onsemi.com/pub_link/Collateral/2N6487-D.PDF
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That must be two output stages in bridge configuration.
One cannot get 9Vrms from a 13.8Vdc supply.
The maximum output must be < 4.6Vac from a single amplifier.
And less when using a 12V battery that is not connected to an active charging system.
P = IV = I²R = V²/R
get your calculator out and use it.
Does your booster amplifier is something like below and would you like to share it .may be it will prove usefull for me.
regards
sudhir.
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