USE Google
You need to help yourself a bit..
But I will give you a hint here.
LTspice Simulator | Analog Devices
I think this software is free of charge, if it isn't then don't blame me, because usually Simulation Software cost quite a bit of money..
Download, install, read "getting started" and if you don't know how to carry on there is always the F1 Key while the Software is open, which will bring up the Help Panel..
And Please don't ask me for help on LtSpice, I do not know Ltspice. Never used it, but I know that many here are using it.. So you're not completely alone.
And if you get an answer from the one or the other, before respond, try first. This guys here are on top level, most of them know what's it all about..
Just this: with 12 volts Rail you will not get a real loud and good Amp.. if you get say a max output voltage of 6 Volts RMS, (what is quite a lot) then your amp will deliver about 6*6:8= 4.5 Watts into 8 Ohms, but I personally doubt that.
Best case you will get something about 4 Volts output..RMS which is then 2 Watts.. So, don't expect the World on that circuit, and exactly here is, where this SPICE Software comes handy, you can try many different settings.. and so on..
Regards
Chris
You need to help yourself a bit..
But I will give you a hint here.
LTspice Simulator | Analog Devices
I think this software is free of charge, if it isn't then don't blame me, because usually Simulation Software cost quite a bit of money..
Download, install, read "getting started" and if you don't know how to carry on there is always the F1 Key while the Software is open, which will bring up the Help Panel..
And Please don't ask me for help on LtSpice, I do not know Ltspice. Never used it, but I know that many here are using it.. So you're not completely alone.
And if you get an answer from the one or the other, before respond, try first. This guys here are on top level, most of them know what's it all about..
Just this: with 12 volts Rail you will not get a real loud and good Amp.. if you get say a max output voltage of 6 Volts RMS, (what is quite a lot) then your amp will deliver about 6*6:8= 4.5 Watts into 8 Ohms, but I personally doubt that.
Best case you will get something about 4 Volts output..RMS which is then 2 Watts.. So, don't expect the World on that circuit, and exactly here is, where this SPICE Software comes handy, you can try many different settings.. and so on..
Regards
Chris
Some other suggestions:
A few lines of reply at a forum may clear up your present problem but just lead to another question and and so on, which is where this thread is going. If you have difficulty understanding online tutorials (some are indeed hopeless as education, regardless of the presenter's qualifications) do get a comprehensive book on Electronic Design at least, such as "The Art of Electronics" by Horowitz and Hill. More focused titles on audio amplifier design by members Bob Cordell or Douglas Self, will then be much clearer and easier to understand. There are plenty of used booksellers in the UK that deal in several editions of these titles, so costs need not be prohibitive.
Computer software (there are several good SPICE programs that are free ) can be downloaded almost anywhere. The programs vary in scope from educational displays to demo aids and parts evaluation tools that run in your browser, through to expensive pro. worktools like Microcap or Altium. You may already be aware that the preferred DIYAudio sim. program is the free and respected LT Spice but it takes time become proficient so I suggest a simpler, intuitive learning type first, like TINA. TINA-TI Simulation tool | TI.com
The point of this is that explanations of how circuits work or what to change in order to make it work as you want, involve a course of electronic design theory to make useful sense and afford some level of understanding. Simulation doesn't substitute for education but it does demonstrate what can or can't work before making changes, sourcing parts or damaging real components in the process. Unfortunately, you still need to study electrical theory in order to make real progress but if doesn't cost much, why not?
A few lines of reply at a forum may clear up your present problem but just lead to another question and and so on, which is where this thread is going. If you have difficulty understanding online tutorials (some are indeed hopeless as education, regardless of the presenter's qualifications) do get a comprehensive book on Electronic Design at least, such as "The Art of Electronics" by Horowitz and Hill. More focused titles on audio amplifier design by members Bob Cordell or Douglas Self, will then be much clearer and easier to understand. There are plenty of used booksellers in the UK that deal in several editions of these titles, so costs need not be prohibitive.
Computer software (there are several good SPICE programs that are free ) can be downloaded almost anywhere. The programs vary in scope from educational displays to demo aids and parts evaluation tools that run in your browser, through to expensive pro. worktools like Microcap or Altium. You may already be aware that the preferred DIYAudio sim. program is the free and respected LT Spice but it takes time become proficient so I suggest a simpler, intuitive learning type first, like TINA. TINA-TI Simulation tool | TI.com
The point of this is that explanations of how circuits work or what to change in order to make it work as you want, involve a course of electronic design theory to make useful sense and afford some level of understanding. Simulation doesn't substitute for education but it does demonstrate what can or can't work before making changes, sourcing parts or damaging real components in the process. Unfortunately, you still need to study electrical theory in order to make real progress but if doesn't cost much, why not?
Hi Friend.
AVG told me that site is infected with some phishing malware and blocking it.
Just warning.
Take care.
We are all trying to help, but you refuse it
But it does not work that way.
It could put out up to 2W RMS if corrected but as is it can only put out some 20 to 50 mW and quite distorted.
You can "acceptably" hear it on high mids but as soon as you want to push some Bass through it it fails miserably, because Bass needs real power (even if 1 or 2 W).
Fine with me, but then why complain about distortion in the first place?
Nobody talked about high quality.
You can EASILY turn your project into a working one, using 90% of what you already have.
Such as OldDIY´s schematic on posts #4 and #7.
Use the transistors you already have, leave them mounted on heatsinks, but correct the wrong circuit.
You´ll only need to buy a couple cheap resistors, maybe a capacitor or two.
Cheap and easy.
I´m not even tring to make you learn Electronics, go figure, just to turn your non working project into a working one.
And no, putting out 20 to 50 milli Watts from a project capable of 2 full watts does not qualify as "working".
Yes, correct the bad design into a working one.
You want to keep it as is?
But it does not work that way.
No, it´s a poorly biased (the understatement of the Century) half braindead project, which must be MODIFIED to work.
It could put out up to 2W RMS if corrected but as is it can only put out some 20 to 50 mW and quite distorted.
You can "acceptably" hear it on high mids but as soon as you want to push some Bass through it it fails miserably, because Bass needs real power (even if 1 or 2 W).
So you are not interested in undistorted sound.
Fine with me, but then why complain about distortion in the first place?
We are suggesting how to make it a working amplifier.
Nobody talked about high quality.
Ok,then follow instructions instead of rejecting them.
You can EASILY turn your project into a working one, using 90% of what you already have.
Such as OldDIY´s schematic on posts #4 and #7.
Use the transistors you already have, leave them mounted on heatsinks, but correct the wrong circuit.
You´ll only need to buy a couple cheap resistors, maybe a capacitor or two.
Cheap and easy.
We are answering from day 1 but you reject advice.
I´m not even tring to make you learn Electronics, go figure, just to turn your non working project into a working one.
And no, putting out 20 to 50 milli Watts from a project capable of 2 full watts does not qualify as "working".
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I have read the tutorials and am not trying to be difficult, i just want to know why lowering the value of R3 from 680 ohms down to 100 ohms is better. There is nothing in the links provided to explain this.
If you can answer this i will end the thread, and thank you for your time.
If you can answer this i will end the thread, and thank you for your time.
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BJT is a current amplifier.
The current through the output transistors is determined by the current in the load (speaker). To get it, you need to supply enough current to the base of the transistors. It is provided by the first stage - a transistor and a resistor. The current through an open transistor is determined by its gain and input signal. The current through the resistor is limited, but must be sufficient for the output transistor to operate. Less resistor resistance means more current and vice versa.
The current through the output transistors is determined by the current in the load (speaker). To get it, you need to supply enough current to the base of the transistors. It is provided by the first stage - a transistor and a resistor. The current through an open transistor is determined by its gain and input signal. The current through the resistor is limited, but must be sufficient for the output transistor to operate. Less resistor resistance means more current and vice versa.
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