we all know very well that transformers are very critical to our amplifiers since they provide the power to the circuit .....
lets suppose for a second that we have two amplifiers that are rated like 150w per chanel and of course we expect the trafo to go down on the voltage while operating at full power .... now how much down of cource will have to do with the quality of the trafo and also the selection ......IE proper trafo for this application ...
then the question is if we have the same quality and specs of transformer in the one amplifier and the same quality and specs in the other but auto transformer instead ......
meaning : if we skip the safety issues for a minute that might ocure by the use of auto transformer which one will have the best performance ?????
normal transformer or autotransformer ????
thank you
lets suppose for a second that we have two amplifiers that are rated like 150w per chanel and of course we expect the trafo to go down on the voltage while operating at full power .... now how much down of cource will have to do with the quality of the trafo and also the selection ......IE proper trafo for this application ...
then the question is if we have the same quality and specs of transformer in the one amplifier and the same quality and specs in the other but auto transformer instead ......
meaning : if we skip the safety issues for a minute that might ocure by the use of auto transformer which one will have the best performance ?????
normal transformer or autotransformer ????
thank you
the autotransformer will be about a half of the size for the same VA rating and regulation.
I would expect them to operate similarly.
But, that's just guessing.
I would expect them to operate similarly.
But, that's just guessing.
TRUE BUT .....
carlos said to me that may be voltage goes down almost the same or even less but the ampers flowing from this circuit is only limited by your socket ....
i am willing to try this
thanks andrew
carlos said to me that may be voltage goes down almost the same or even less but the ampers flowing from this circuit is only limited by your socket ....
i am willing to try this
thanks andrew
On the auto transformer, one leg will be DC coupled.
On the "regular" transformer, neither leg will be DC coupled.
Could make a difference in ways that have nothing to do with voltage drop or current capability under load?
Fwiw, due to the lack of safety isolation, I'd NEVER ever use one for the power line. One miswired line cord and people could get very dead quickly...
_-_-bear
On the "regular" transformer, neither leg will be DC coupled.
Could make a difference in ways that have nothing to do with voltage drop or current capability under load?
Fwiw, due to the lack of safety isolation, I'd NEVER ever use one for the power line. One miswired line cord and people could get very dead quickly...
_-_-bear
When they publish the transformer is 100 Volts AC and 1 ampere
They use to say that you have a 500 watts or 500VA transformer.... VA is Volts multiplied by Amperes.... and Volts multiplied by Amperes is WATTS too.
They intend to say that you will be able to drain 1 ampere and still have 100 volts (more or less 20 percent of voltage tollerance).
But they drop.... this is not the real thing as i could see.... at least in my country (maybe third world country problem).
I think, a good idea to those folks would be to say the transformer is guaranteed to, lets say, 500 watts when the transformer is able to give you more.....but to save money into the manufacturing of transformers, they use tell you the transformer is able to 500 watts when the unit will give you LESS.
Well....of course folks, i accept this can be a regional problem...my country problem.
But the best idea is to buy, or calculate when winding, or selecting iron cores, to select twice your needs... this way you will really have what you want...and maybe a little bit more.
Auto transformers are vastly used in my country as AC stabilizers...It is a single coil with taps (many turns coil with 1.5 milimeters diameter copper wire).... those taps are controled by relays that switch the needed tap to control the AC voltage...a chip senses the AC input voltage drop and fast switch to a higher voltage tap into the autotransformer.... works great.... but has voltage drops depending the consumption alike others, more standard, traditional and common primary and secondary types of transformers.
I use to wind them in my home.... but i do not use to touch the primary..... i use to measure the secondary AC volts and lets say i could find 100 volts (for instance, example only)... then i rewound, remove, uncoil the transformer and i counting the turns i perceive was 100 turns....so...very simple... 1 turn to each volt.
If i want 30 plus 30 volts.... so, i will need 30 plus 30 turns... with the biggest wire (diameter) i can find that can be inside the coil limits (sorry this is eye calculation, cannot explain how to decide that..have to do to learn doing.... try and error basis).... then i run two wires in parallel.... long wires attached to my house doors to be straigth and then 30 turns....
The starting point will be twisted together and will be your center tap..... when finish to wind your coil, you gonna have two wires...each one will have 30 volts (1 volts each turn..very easy).
The power:
If your transformer had 100 turns, 100 volts AC and lets say 1 ampere.... a 100 watts transformer (volts multiplied by amperes result watts or VA).... you will not be able to obtain more than 100 watts.... a 100 watts transformer core, will always give you 100 watts or MUCH LESS than that because of losses...bad winding and those things...manual work is less precise to wound things....but you have two coils... this helps a little and only 30 volts...... this means your 100 watts will be distributed into your coils..... something alike 30 plus 30 volts and 1.6 amperes may be obtained, as you have used bigger wire diameter you may have nice power.
So...to manually change things... in advance select huge transformers, because the losses you gonna have...heavy ones, big ones, and another good idea is to calculate your AC voltage 20 percent bigger than you needs.... as the transformer will loose voltage when drained... will have voltage drop.... during those moments your amplifier will have the good voltage to operate, and sligthly bigger while in stand by mode.
My philosophy and small money, made me build those things, they are easy but we have things to learn doing...if you fail doing, it will turn a buzzer vibrating metal sheet.
My examples and calculations are not precise.... also i had so many surprises doing those transformers, some results better than i was expecting, that i cannot guarantee my numbers...but for sure Andrew T can help into those calculations.
regards,
Carlos
They use to say that you have a 500 watts or 500VA transformer.... VA is Volts multiplied by Amperes.... and Volts multiplied by Amperes is WATTS too.
They intend to say that you will be able to drain 1 ampere and still have 100 volts (more or less 20 percent of voltage tollerance).
But they drop.... this is not the real thing as i could see.... at least in my country (maybe third world country problem).
I think, a good idea to those folks would be to say the transformer is guaranteed to, lets say, 500 watts when the transformer is able to give you more.....but to save money into the manufacturing of transformers, they use tell you the transformer is able to 500 watts when the unit will give you LESS.
Well....of course folks, i accept this can be a regional problem...my country problem.
But the best idea is to buy, or calculate when winding, or selecting iron cores, to select twice your needs... this way you will really have what you want...and maybe a little bit more.
Auto transformers are vastly used in my country as AC stabilizers...It is a single coil with taps (many turns coil with 1.5 milimeters diameter copper wire).... those taps are controled by relays that switch the needed tap to control the AC voltage...a chip senses the AC input voltage drop and fast switch to a higher voltage tap into the autotransformer.... works great.... but has voltage drops depending the consumption alike others, more standard, traditional and common primary and secondary types of transformers.
I use to wind them in my home.... but i do not use to touch the primary..... i use to measure the secondary AC volts and lets say i could find 100 volts (for instance, example only)... then i rewound, remove, uncoil the transformer and i counting the turns i perceive was 100 turns....so...very simple... 1 turn to each volt.
If i want 30 plus 30 volts.... so, i will need 30 plus 30 turns... with the biggest wire (diameter) i can find that can be inside the coil limits (sorry this is eye calculation, cannot explain how to decide that..have to do to learn doing.... try and error basis).... then i run two wires in parallel.... long wires attached to my house doors to be straigth and then 30 turns....
The starting point will be twisted together and will be your center tap..... when finish to wind your coil, you gonna have two wires...each one will have 30 volts (1 volts each turn..very easy).
The power:
If your transformer had 100 turns, 100 volts AC and lets say 1 ampere.... a 100 watts transformer (volts multiplied by amperes result watts or VA).... you will not be able to obtain more than 100 watts.... a 100 watts transformer core, will always give you 100 watts or MUCH LESS than that because of losses...bad winding and those things...manual work is less precise to wound things....but you have two coils... this helps a little and only 30 volts...... this means your 100 watts will be distributed into your coils..... something alike 30 plus 30 volts and 1.6 amperes may be obtained, as you have used bigger wire diameter you may have nice power.
So...to manually change things... in advance select huge transformers, because the losses you gonna have...heavy ones, big ones, and another good idea is to calculate your AC voltage 20 percent bigger than you needs.... as the transformer will loose voltage when drained... will have voltage drop.... during those moments your amplifier will have the good voltage to operate, and sligthly bigger while in stand by mode.
My philosophy and small money, made me build those things, they are easy but we have things to learn doing...if you fail doing, it will turn a buzzer vibrating metal sheet.
My examples and calculations are not precise.... also i had so many surprises doing those transformers, some results better than i was expecting, that i cannot guarantee my numbers...but for sure Andrew T can help into those calculations.
regards,
Carlos
There's no possible magic or miracle in such things
If your transformer is 100 watts, and you change it to the voltage you want, it will continue to be 100 watts.
A hundred watts transformer will not be able to make an audio amplifier to produce more than a 100 watts of audio.... in the reality, around 60 watts will be produce in your amplifier connected to that 100 watts transformer.
I know you are experienced..but there are folks that has doubts about that, beginners and very young folks.... some of them think they can connect two amplifiers and then will have bigger power...negative.... that 60 watts i have explained before will be distributed into those 2 amplifiers.... they will produce 30 watts each one.... the voltage will drop a lot under consumption and the power will be around 60 watts....so... everything is connected, and depends on the transformer power...and this depends how huge and heavy and big it is... also the material quality of course...but how huge, how heavy and how big is the most important thing.
Here, down in Brazil, my Orkut friends are all building their own transformers.... rewinding transformers (rewound?)...well.... dismounting and producing another coil to the secondary once again.... this way they are using junk transformers, from old equipments... this turns cheaper their hobby.
I have published, in 2004, instructions about that... was for a guy from Israel..... the made his own transformer and was happy....but do not know the thread name....if you want it, sorry, have to search in 2004 into Destroyer X threads.
Sorry to invade in such way your thread, but as you had mentioned my name, i felt the obligation to come and say some words.
Carlos
If your transformer is 100 watts, and you change it to the voltage you want, it will continue to be 100 watts.
A hundred watts transformer will not be able to make an audio amplifier to produce more than a 100 watts of audio.... in the reality, around 60 watts will be produce in your amplifier connected to that 100 watts transformer.
I know you are experienced..but there are folks that has doubts about that, beginners and very young folks.... some of them think they can connect two amplifiers and then will have bigger power...negative.... that 60 watts i have explained before will be distributed into those 2 amplifiers.... they will produce 30 watts each one.... the voltage will drop a lot under consumption and the power will be around 60 watts....so... everything is connected, and depends on the transformer power...and this depends how huge and heavy and big it is... also the material quality of course...but how huge, how heavy and how big is the most important thing.
Here, down in Brazil, my Orkut friends are all building their own transformers.... rewinding transformers (rewound?)...well.... dismounting and producing another coil to the secondary once again.... this way they are using junk transformers, from old equipments... this turns cheaper their hobby.
I have published, in 2004, instructions about that... was for a guy from Israel..... the made his own transformer and was happy....but do not know the thread name....if you want it, sorry, have to search in 2004 into Destroyer X threads.
Sorry to invade in such way your thread, but as you had mentioned my name, i felt the obligation to come and say some words.
Carlos
Auto-transformers are only used to adjust for voltage
differences and do not have separate galvanically isolated
primary and seconday. Do not use for Amp as it basically
places the whole amp hot with respect to the mains line!!
The main idea behind using transformers (either step-up,
step down, or 1/1) is really to isolate the amp from the
mains line!
As far as sound. I think the isolating transformer would
filter more dirt and grunge off the line as well. The auto-
tranny would let more line noise, harmonics, etc. get through.
differences and do not have separate galvanically isolated
primary and seconday. Do not use for Amp as it basically
places the whole amp hot with respect to the mains line!!
The main idea behind using transformers (either step-up,
step down, or 1/1) is really to isolate the amp from the
mains line!
As far as sound. I think the isolating transformer would
filter more dirt and grunge off the line as well. The auto-
tranny would let more line noise, harmonics, etc. get through.
carlos .....
thank you for your very usefull input ....i will keep everything in mind
though i will wind an auto transformer and see about the performance
coloradosound thank you also for your input ....i am very familiar with all this safety issues and use of auto transformers ..... still though i would like to try to see the overall performance of a device like that
thank you all
thank you for your very usefull input ....i will keep everything in mind
though i will wind an auto transformer and see about the performance
coloradosound thank you also for your input ....i am very familiar with all this safety issues and use of auto transformers ..... still though i would like to try to see the overall performance of a device like that
thank you all
sakis,
put an isolating transformer in the mains line first.
Test both the conventional and the auto when either are fed from the isolating.
put an isolating transformer in the mains line first.
Test both the conventional and the auto when either are fed from the isolating.
andrew
thanks for your advice .....
i had this in mind anyway but the circuit i am working with has isolation trafo in the signal input so if there is any danger this is limited in the speaker cables ......
the all thing is designed to operate like that and might be inderesting circuit that produces a hell of a lot of power for a device that only weights 13kg ....
the only thing is that this circuit is almost mains operated so posting a schematic or anything else will be quickly removed by moderators .....
( here i would like to state that at the age of 42 and so many electronics produced ,modified , operated..... and with probably more than 10.000.000 wats installed in clubs, theaters, and PA rentals since i started at the age of 13..... of course i put safety first .... but still a mains operated amp will be inetersting thing and very powerfull to be presented somewhere in this forum with probably very big notification that voltages related to this device might kill somebody )
but thats just my opinion
people produce or modify cars that can speed up to 300 klm/hr dont you think that this even more worst or the same fatal ????
thanks for your advice .....
i had this in mind anyway but the circuit i am working with has isolation trafo in the signal input so if there is any danger this is limited in the speaker cables ......
the all thing is designed to operate like that and might be inderesting circuit that produces a hell of a lot of power for a device that only weights 13kg ....
the only thing is that this circuit is almost mains operated so posting a schematic or anything else will be quickly removed by moderators .....
( here i would like to state that at the age of 42 and so many electronics produced ,modified , operated..... and with probably more than 10.000.000 wats installed in clubs, theaters, and PA rentals since i started at the age of 13..... of course i put safety first .... but still a mains operated amp will be inetersting thing and very powerfull to be presented somewhere in this forum with probably very big notification that voltages related to this device might kill somebody )
but thats just my opinion
people produce or modify cars that can speed up to 300 klm/hr dont you think that this even more worst or the same fatal ????
Re: When they publish the transformer is 100 Volts AC and 1 ampere
Carlos, it is not the same. Watt units used in clear resistive loads. VA units used in complex loads such a transformer which presents also ZL. The relation which express the power in a complex load it is very common and well known: P = V X A X cosö where cosö represents the trigonometrical calculation of the angle "ö" between voltage and current caused from the inductive part of the complex resistance presented when a transformer is powered to supply a load. In a further mathematic analysis, we have to make with imaginary numbers ( j X ö ).
Fotios
destroyer X said:
Carlos, it is not the same. Watt units used in clear resistive loads. VA units used in complex loads such a transformer which presents also ZL. The relation which express the power in a complex load it is very common and well known: P = V X A X cosö where cosö represents the trigonometrical calculation of the angle "ö" between voltage and current caused from the inductive part of the complex resistance presented when a transformer is powered to supply a load. In a further mathematic analysis, we have to make with imaginary numbers ( j X ö ).
Fotios
Re: andrew
Saki, how came in your mind the idea of use of autotransformer? Because we are using this type usually in variacs for lab use. Except if i don't understood well what you have in your mind.
Send me e-mail.
Fotis
sakis said:
Saki, how came in your mind the idea of use of autotransformer? Because we are using this type usually in variacs for lab use. Except if i don't understood well what you have in your mind.
Send me e-mail.
Fotis
Well.... you know those things better than i know...so....go ahead
explaining with more details, this way you gonna contribute to our forum friends, giving them more informations.
As i told folks, i have some limited skills on that... have learned burning my fingers, the ones have better knowledge should help folks to understand that a little bit deeper and better, also to correct my errors and clarify non clear informations.
Fotios, you are saying those things are not exactly this way, a little bit different and maybe more deep and complicated...informing those things as beeing not so easy.....well, despite our problems with the english language (not your mother language and not mine too), i suppose i told that i do not understand deeply this subject...but i would be happy to learn....of course.
I have already found, and realised, that i need more inputs, more informations, a good teacher, a friendly explanation about the subject.... i would like to know "things i do not know"
thank you,
Carlos
explaining with more details, this way you gonna contribute to our forum friends, giving them more informations.
As i told folks, i have some limited skills on that... have learned burning my fingers, the ones have better knowledge should help folks to understand that a little bit deeper and better, also to correct my errors and clarify non clear informations.
Fotios, you are saying those things are not exactly this way, a little bit different and maybe more deep and complicated...informing those things as beeing not so easy.....well, despite our problems with the english language (not your mother language and not mine too), i suppose i told that i do not understand deeply this subject...but i would be happy to learn....of course.
I have already found, and realised, that i need more inputs, more informations, a good teacher, a friendly explanation about the subject.... i would like to know "things i do not know"
thank you,
Carlos
i will
try to post a schematic or send it to you by pm. since moderators may have diferent opinion
here is the circuit http://www.electronics-lab.com/projects/audio/043/index.html
try to post a schematic or send it to you by pm. since moderators may have diferent opinion
here is the circuit http://www.electronics-lab.com/projects/audio/043/index.html
by the way .....
its very nice to see you here my friend fotios ......
i presumed that at this time of the year and the day you were supposed to be on a nice beach surrounded by pretty girls and beers ha ha ha ha
its very nice to see you here my friend fotios ......
i presumed that at this time of the year and the day you were supposed to be on a nice beach surrounded by pretty girls and beers ha ha ha ha
Re: Well.... you know those things better than i know...so....go ahead
Ah Carlos; I wish in you and in your familly the best always. In depth, you can't imagine how big is my love to you!
You are a very good man! Smak! Smak! To you and in your familly. As you can see we the Greeks, except Dorians and Macedonians, we are very open-hearted people.
For the record, my name has a clear Byzantine origin (Byzantium was the east part of the latter Roman empire with capital the Constantinople)
Fotios in Greece
Photius in Latin
destroyer X said:
Ah Carlos; I wish in you and in your familly the best always. In depth, you can't imagine how big is my love to you!
You are a very good man! Smak! Smak! To you and in your familly. As you can see we the Greeks, except Dorians and Macedonians, we are very open-hearted people.
For the record, my name has a clear Byzantine origin (Byzantium was the east part of the latter Roman empire with capital the Constantinople)
Fotios in Greece
Photius in Latin
Re: by the way .....
Saki
èá ôï êïéôáîù ôï áðïãåõìá êáé èá óïõ áðáíôçóù, ãéáôé å÷ù ðéåé ôá ôóéðïõñá ìïõ ôùñá êáé ðåéíáù. Áí ãêñéíéáæïõí ïé êïõôïöñáãêïé ãéá ôá åëëçíéêá, ñéîôïõò ìéá ìåôáöñáóç.
Fotis
sakis said:
Saki
èá ôï êïéôáîù ôï áðïãåõìá êáé èá óïõ áðáíôçóù, ãéáôé å÷ù ðéåé ôá ôóéðïõñá ìïõ ôùñá êáé ðåéíáù. Áí ãêñéíéáæïõí ïé êïõôïöñáãêïé ãéá ôá åëëçíéêá, ñéîôïõò ìéá ìåôáöñáóç.
Fotis
We are the world Fótios... i have Italian in my blood
Danesi (from Dennmark)... also from Netherlands... also from Portugal, and from Africa and from Brazilian Indians, the real brazilians we have.
We are the world...in USA there are many greeks...here in my country too...we are in whole world.
èá Þèåëå ìüíï Ýíá ðñÜãìá
êüóìïò åßíáé ìéá ìéêñÞ ðüëç .... Ýíá ÷ùñéü
ôùí áíèñþðùí ðïõ ìïéñÜæïíôáé ãåíåôéêÞò êëçñïíïìéÜò
êïéíÝò ãéá üëïõò ôïõò áíèñþðïõò óôïí ðëáíÞôç
This means...the world is a big village
regards and thanks,
Carlos
Danesi (from Dennmark)... also from Netherlands... also from Portugal, and from Africa and from Brazilian Indians, the real brazilians we have.
We are the world...in USA there are many greeks...here in my country too...we are in whole world.
èá Þèåëå ìüíï Ýíá ðñÜãìá
êüóìïò åßíáé ìéá ìéêñÞ ðüëç .... Ýíá ÷ùñéü
ôùí áíèñþðùí ðïõ ìïéñÜæïíôáé ãåíåôéêÞò êëçñïíïìéÜò
êïéíÝò ãéá üëïõò ôïõò áíèñþðïõò óôïí ðëáíÞôç
This means...the world is a big village
regards and thanks,
Carlos
Attachments
Re: i will
I don't know, probably it is a stupid idea. It came in my mind by looking the original plan, how we can isolate the mains rails. As well, maybe it is a starting point for further investigation from other members. With each reservation, i quote the scheme in pdf. The idea is the use of two bridge rectifiers instead one, as you can see in the scheme.
Fotios
sakis said:
I don't know, probably it is a stupid idea. It came in my mind by looking the original plan, how we can isolate the mains rails. As well, maybe it is a starting point for further investigation from other members. With each reservation, i quote the scheme in pdf. The idea is the use of two bridge rectifiers instead one, as you can see in the scheme.
Fotios
Re: We are the world Fótios... i have Italian in my blood
What is wrong with Sweden people, Carlos.
As you foget to mention us.
We are quite many here at www.diyaudio.com
You still hate me mister lineup ???
Just joking of course 😉 Sweden is a very small country.
Smaller than Brasil .. for sure.
thanks sakis from Hellas.
I got the 5.000 Watt supply circuit from your posted link.
Crazy high powerrrrrrrrrrrrrrrrrr!
destroyer X said:
What is wrong with Sweden people, Carlos.
As you foget to mention us.
We are quite many here at www.diyaudio.com
You still hate me mister lineup ???
Just joking of course 😉 Sweden is a very small country.
Smaller than Brasil .. for sure.
thanks sakis from Hellas.
I got the
5.000 Watt supply circuit from your posted link.Crazy high powerrrrrrrrrrrrrrrrrr!
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