Shouldnt that 10k pot be on the bottom of the vbe multiplier incase it goes open at some point. The resistor is less likely to go open, pots are far more likely to.
Nice demo. Just a thought on your harmonics, the dominant components seem to be even order and your nearest odd order component is around 10dB below. So you could probably get an extra 10dB on your THD by using a fully differential circuit.
I wanna have your bench 😢 goddamn with your set up. At my pace , it would take me prob 10years to have those goodies. Thank you for the vid, I will copy it and test a few things. I can't believe I understand everything, I'm amazed at myself.
I really like your video I desing an amplier similar to that 2 years ago on a breadboard. Be carrefull with your speakers because if a connection fails on the breadboard it might be disastrous...
Hi! If you don't mind i have a few questions. I am a beginner electronics hobbyist, so please forgive me if i get something completely wrong. 1- To drive 8ohm speakers with this circuit should i just increase the input voltage? i checked the datasheet for the output transistors and they are quite beefy, will the opamp be able to take, lets say +and - 24v? 2- would you recommend an input coupling capacitor to isolate dc or do some filtering after the preamp? 3- Can you give some advice on how to check the bias without a scope? Thank you so much for your time in advance. I have built a class b amp and the crossover distortion is anoying :) P.s.: i intend to build this amp 3 times, to make a 2.1 stereo amp driving 2 8ohm speakers with 2 16ohm tweeters and a subwoofer on the third channel (with 5k resistors to average the signals) with a rc low pass filter(should i go LC?).
No need to apologize for asking questions friend! Here are my answers to your questions: 1) No need to increase the supply voltage if you want to drive 8Ω speaker - you will just get half the power. But if your intension is to get more power, then yes you can increase the supply voltage. The op-amp can take up to ±22V or 44V but it isn’t recommended. If you require higher power you will have to design a discrete op-amp to handle the large supply voltage (Stay tuned in upcoming videos regarding discrete op-amps for audio applications). 2) Yes you need to use input coupling capacitor since the op-amp will want to see a signal without any dc offset which might limit the low frequency performance of the power amplifier unless you put a large capacitor (depending on your source impedance of course). 3) Yes you can check the bias current through the main output transistors using a multimeter. To do this, use the ‘mv’ scale on your meter and measure the voltage across the emitter ballasting resistors (0.33Ω for the power amplifier shown in the video) and calculate the quiescent current using ohms law while you adjust the 10k pot in the vbe multiplier transistor.
Thank you so much! i already ordered the parts and am anxious to start! Regarding the opamp, i considered using a tl072 that can take +- 36v and is a low noise amplifier (also I already have a few here) but i was worried because it is a jfet input, could it cause problems? Thanks again!
also, what kind of current am i looking for? Should i just be sure that both transistors have a minimum quiescent current or is there an ideal value? (i am using the exact same transistors). I chose 5w resistors for ballast, should i use 10w? Again, thank you very much for your patience! :)
The TL072 is inferior compared to NE5534 in all aspects except for input resistance. If you have the option use NE5534. NE5534 is also five times less noisy than TL072 and is popular for audio applications. JFET input will cause no issue; in fact that is the only good merit TL072 has over NE5534.
It all depends on the transistor you are using since VBE(on) will be different for different transistors. What matters is though; the transistors are just about turned on so that when a signal increases above zero, the emitter of output transistors follows it. You get to choose the quiescent current depending on how much quiescent power dissipation is tolerable. Take a look at the following example calculation: drive.google.com/file/d/13DOrUl2VbzSZZHRN-sCXjX2ZebzFGsjC/view?usp=sharing Therefore for the example in the link, you set your VBE multiplier circuit to have about 1.2V and measure across the emitter ballasting resistor to know exactly how much current is flowing.
I don't like bootstrap , you don't find it in any high end av receiver circuit and in LM3886, however ,it is there in tda7293 and tda7294 . but LM3886 audio quality is good
Shouldnt that 10k pot be on the bottom of the vbe multiplier incase it goes open at some point. The resistor is less likely to go open, pots are far more likely to.
Nice demo. Just a thought on your harmonics, the dominant components seem to be even order and your nearest odd order component is around 10dB below. So you could probably get an extra 10dB on your THD by using a fully differential circuit.
Megépítettem és nagyon szépen szól. Nagyon szépen köszönöm a segítséget.
Thank you for posting such informative videos on electronic circuitry !
Simple but very effective. Thank you!
Very good explanation! Thanks.
I wanna have your bench 😢 goddamn with your set up. At my pace , it would take me prob 10years to have those goodies. Thank you for the vid, I will copy it and test a few things. I can't believe I understand everything, I'm amazed at myself.
I really like your video I desing an amplier similar to that 2 years ago on a breadboard. Be carrefull with your speakers because if a connection fails on the breadboard it might be disastrous...
EXCELENTE VIDEO
Op amp drive huh🙃
It will be helpful if you can tell me In which book I can learn designing transistor amplifier with calculation help me?
What is the minimum value of the DC biasing current in class A output stage? Explain you answer.
Thank you for the video. Can you explain 1969 amp? Why it dont need PNP transistor in its design?
Because its class A single ended
Hi, sir I will give +30 0 -30v. Its working. Any components change. Pls suggest.
Hi! If you don't mind i have a few questions. I am a beginner electronics hobbyist, so please forgive me if i get something completely wrong. 1- To drive 8ohm speakers with this circuit should i just increase the input voltage? i checked the datasheet for the output transistors and they are quite beefy, will the opamp be able to take, lets say +and - 24v? 2- would you recommend an input coupling capacitor to isolate dc or do some filtering after the preamp? 3- Can you give some advice on how to check the bias without a scope? Thank you so much for your time in advance. I have built a class b amp and the crossover distortion is anoying :) P.s.: i intend to build this amp 3 times, to make a 2.1 stereo amp driving 2 8ohm speakers with 2 16ohm tweeters and a subwoofer on the third channel (with 5k resistors to average the signals) with a rc low pass filter(should i go LC?).
No need to apologize for asking questions friend! Here are my answers to your questions:
1) No need to increase the supply voltage if you want to drive 8Ω speaker - you will just get half the power. But if your intension is to get more power, then yes you can increase the supply voltage. The op-amp can take up to ±22V or 44V but it isn’t recommended. If you require higher power you will have to design a discrete op-amp to handle the large supply voltage (Stay tuned in upcoming videos regarding discrete op-amps for audio applications).
2) Yes you need to use input coupling capacitor since the op-amp will want to see a signal without any dc offset which might limit the low frequency performance of the power amplifier unless you put a large capacitor (depending on your source impedance of course).
3) Yes you can check the bias current through the main output transistors using a multimeter. To do this, use the ‘mv’ scale on your meter and measure the voltage across the emitter ballasting resistors (0.33Ω for the power amplifier shown in the video) and calculate the quiescent current using ohms law while you adjust the 10k pot in the vbe multiplier transistor.
Thank you so much! i already ordered the parts and am anxious to start! Regarding the opamp, i considered using a tl072 that can take +- 36v and is a low noise amplifier (also I already have a few here) but i was worried because it is a jfet input, could it cause problems? Thanks again!
also, what kind of current am i looking for? Should i just be sure that both transistors have a minimum quiescent current or is there an ideal value? (i am using the exact same transistors). I chose 5w resistors for ballast, should i use 10w? Again, thank you very much for your patience! :)
The TL072 is inferior compared to NE5534 in all aspects except for input resistance. If you have the option use NE5534. NE5534 is also five times less noisy than TL072 and is popular for audio applications. JFET input will cause no issue; in fact that is the only good merit TL072 has over NE5534.
It all depends on the transistor you are using since VBE(on) will be different for different transistors. What matters is though; the transistors are just about turned on so that when a signal increases above zero, the emitter of output transistors follows it. You get to choose the quiescent current depending on how much quiescent power dissipation is tolerable. Take a look at the following example calculation:
drive.google.com/file/d/13DOrUl2VbzSZZHRN-sCXjX2ZebzFGsjC/view?usp=sharing
Therefore for the example in the link, you set your VBE multiplier circuit to have about 1.2V and measure across the emitter ballasting resistor to know exactly how much current is flowing.
👍
I don't like bootstrap , you don't find it in any high end av receiver circuit and in LM3886, however ,it is there in tda7293 and tda7294 . but LM3886 audio quality is good
Esquematic Photo... unreadable... Please
High order harming is way too high, their bad can be described as n^2/n, not good performance on such design.
+30 0 -30v its working or not. Any components change. Pls tell me sir.
It will not work with that power supply. The op-amp used (NE5534) will not be able to operate at that high supply voltage.
That is correct Tekellamer! The NE5534 max voltage limit of +/-22V.
Smith Kerona thank u
You are welcome!
@@SmithKerona how if I use regulator voltage for the chip ? So can I use higher voltage to amplifier ?