Hi geraldfryjr!Here is a link to the one that I made a while back,
http://www.diyaudio.com/forums/chip...own-supply-what-could-happen.html#post3695968
It worked good.
I will be using a ADA4700-1 high voltage opamp on the next version in order to get more voltage swing out of it.
http://www.analog.com/static/imported-files/data_sheets/ADA4700-1.pdf
jer
I have the power supply Ucc = +/-(37...40)V/250VA.
For this power supply I need a good power amplifier for 4R speakers!
thanks!
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If you want to use the type of circuit that you have posted you must use an opamp that can handle that much voltage.
Else the output voltage swing of your amp will be no more than what the opamp itself can produce and/or result in a burn't opamp due to the overvoltage as the most common ones are only rated at +/- 18V to 22V.
There are ways to increase the output voltage swing and use a higher supply voltage on such opamps but I have not tried any of those techniques yet.
http://m.eet.com/media/1152270/24127-45890.pdf
Have you considered using a chipamp such as the TDA7293/94 or the LM3886 and lm4780 (dual LM3886's)?
They are basically power opamps that do run in the voltage range of the power supply that you are plan on using.
For a 4 ohm load I would consider using a paralleled design such as the PA100 (2x) or PA150 (3x) using the LM3886's.
There are plenty of parallel designs using the TDA729x chips as well.
The cool thing about these chips as you can run one of them as a master and add more as slaves with very little amount of extra components.
http://www.diyaudio.com/forums/chip-amps/197398-tda7293-single-bridge-parallel.html#post2729693
You can also use a current boosted output stage with all of them as well here is a thread that has a lot of support on such a design, However I think that it needs to be refined a bit but it works and some seem to like the result,
http://www.diyaudio.com/forums/chip...istors-amp-tda7293-come-also.html#post2904001
I have not built one yet to run it through its paces as I don't have any suitable output transistors yet.
Here are a couple more HV opamps that you can look into as well,
http://www.diyaudio.com/forums/chip...own-supply-what-could-happen.html#post3686106
Using something like the LM4702 and LME49810/11/30's and a few output devices is another very quality alternative.
There are many threads here on such designs.
Depending on your construction skills I would look into a chipamp designs for a place to start.
If you prefer a discrete design check out some of Apex's designs, They are very simple quality designs and can be modified very easily to your power requirement if you need more by adding more output devices.
Here is just one of his threads, it is very long and you will have to scroll through it to find something that fits your needs,
http://www.diyaudio.com/forums/solid-state/164093-100w-ultimate-fidelity-amplifier.html#post2135804
He has much larger power designs as well, But for 4 ohm's I would use at least 4 output devices and there are many of such variations of his designs in that thread.
jer
P.S. As the name of the thread is about using the ua741.....Do use something better if you have anything available to you !!!
Else the output voltage swing of your amp will be no more than what the opamp itself can produce and/or result in a burn't opamp due to the overvoltage as the most common ones are only rated at +/- 18V to 22V.
There are ways to increase the output voltage swing and use a higher supply voltage on such opamps but I have not tried any of those techniques yet.
http://m.eet.com/media/1152270/24127-45890.pdf
Have you considered using a chipamp such as the TDA7293/94 or the LM3886 and lm4780 (dual LM3886's)?
They are basically power opamps that do run in the voltage range of the power supply that you are plan on using.
For a 4 ohm load I would consider using a paralleled design such as the PA100 (2x) or PA150 (3x) using the LM3886's.
There are plenty of parallel designs using the TDA729x chips as well.
The cool thing about these chips as you can run one of them as a master and add more as slaves with very little amount of extra components.
http://www.diyaudio.com/forums/chip-amps/197398-tda7293-single-bridge-parallel.html#post2729693
You can also use a current boosted output stage with all of them as well here is a thread that has a lot of support on such a design, However I think that it needs to be refined a bit but it works and some seem to like the result,
http://www.diyaudio.com/forums/chip...istors-amp-tda7293-come-also.html#post2904001
I have not built one yet to run it through its paces as I don't have any suitable output transistors yet.
Here are a couple more HV opamps that you can look into as well,
http://www.diyaudio.com/forums/chip...own-supply-what-could-happen.html#post3686106
Using something like the LM4702 and LME49810/11/30's and a few output devices is another very quality alternative.
There are many threads here on such designs.
Depending on your construction skills I would look into a chipamp designs for a place to start.
If you prefer a discrete design check out some of Apex's designs, They are very simple quality designs and can be modified very easily to your power requirement if you need more by adding more output devices.
Here is just one of his threads, it is very long and you will have to scroll through it to find something that fits your needs,
http://www.diyaudio.com/forums/solid-state/164093-100w-ultimate-fidelity-amplifier.html#post2135804
He has much larger power designs as well, But for 4 ohm's I would use at least 4 output devices and there are many of such variations of his designs in that thread.
jer
P.S. As the name of the thread is about using the ua741.....Do use something better if you have anything available to you !!!
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Hi geraldfryjr!
I have the power supply Ucc = +/-(37...40)V/250VA.
For this power supply I need a good power amplifier for 4R speakers!
thanks!
250VA will be fine...
Sajti
Yes. And it's much easier to establish, with a small heatsink, which mounted together with the 3 TO-126 devices. A small piece of aluminium or copper sheet is enough.
Sajti
Hi,There are two circuits that were posted.
I was referring to the First circuit in post 1 as that is the same circuit I had made, not the one that uses a Vbe multiplier stage.
Sorry for the confusion.
jer
What kind of sound gives you satisfied?
Are audio amplifier is made stable by post1?
thank you!
I didn't have running long enough to play music through and critique it as it was just something I through together to see if it worked on my bench and it did!!
I started with a TL072 and everything looked good and then I put a LME49860 in it and all of the waveform's looked very good.
I did have to compensate it for high frequency oscillations when I put the higher gain bandwidth opamp in it.
I plan on rebuilding it some time soon on a PCB and upping the amount of output devices as well as using a higher voltage opamp for more reliable power output.
I also plan on biasing it harder into the class A region as it is quite adjustable.
The square wave looked as good as it would coming straight from the opamp.
But like I said, I didn't mess with it for very long as I had another pressing project that I had to do at the time but it was a very interesting and simple project.
jer
I started with a TL072 and everything looked good and then I put a LME49860 in it and all of the waveform's looked very good.
I did have to compensate it for high frequency oscillations when I put the higher gain bandwidth opamp in it.
I plan on rebuilding it some time soon on a PCB and upping the amount of output devices as well as using a higher voltage opamp for more reliable power output.
I also plan on biasing it harder into the class A region as it is quite adjustable.
The square wave looked as good as it would coming straight from the opamp.
But like I said, I didn't mess with it for very long as I had another pressing project that I had to do at the time but it was a very interesting and simple project.
jer
Hi Jer!I didn't have running long enough to play music through and critique it as it was just something I through together to see if it worked on my bench and it did!!
I started with a TL072 and everything looked good and then I put a LME49860 in it and all of the waveform's looked very good.
I did have to compensate it for high frequency oscillations when I put the higher gain bandwidth opamp in it.
I plan on rebuilding it some time soon on a PCB and upping the amount of output devices as well as using a higher voltage opamp for more reliable power output.
I also plan on biasing it harder into the class A region as it is quite adjustable.
The square wave looked as good as it would coming straight from the opamp.
But like I said, I didn't mess with it for very long as I had another pressing project that I had to do at the time but it was a very interesting and simple project.
jer
When the whole thing (schematic-diagram and PCB) show here.
For Ucc=+/-37...40V power supply!!
thank you!
something you can try
Hi andrewlebon!
Is this аудио amplifier have made? If you have made such things?
If you are unable display top and lay out the PCB in pdf
thanks!
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