Magnifico, grandioso !! ⭐⭐⭐⭐⭐

nice power amplifier. succses for you. good luck

I wish electronics was taught like this in college. Info is easier to absorb because of an objective which is to design.

To do electronics buy modules and solder, to learn electronics build from scratch...

looks like a nice circuit

Very good video.

Nice video, thanks :)

thank you very much!

I also make videos about audio, electronic and I also like your video. They are helpful for audiences

How much might it cost to hire an EE to design a custom schematic of a power amplifier? Do you ever take on custom jobs?

Good music..good courses

There are lots of sections or sub-circuits in this complex design that I hoped would be explained here or in part 2 but part two is just a simple 2 transistor AB circuit. Will you be giving any more comments on this much more complex design? (e.g. comments on what the feedback circuit from output to the diff amp is accomplishing?). There are lots of things in this design that are not obvious to those trying to understand something this complex.

thank you very much

The input capacitor has a very large value and has no resistor between it and the base of the input transistor. Input capacitors are usually around 10 uF, (and preferably non polarised) with a resistor of 10 K - 22 K. Why did you design your circuit this way?

Why the input capacitor is so large?

Nice and very good explanation. Can you tell me Why the powe loss at output is taken as 4v?

the 2nd stage how works?

WHAT U THINK "CASECODE+DUAL POLE COMPENSATION 🤔 I THINK ITS POSSIBLE TO DO THAT, IS IT?🤔

You should add a capacitor from your feedback translator base to 10k resistor. You don't want gain at DC, you just want the amp to servo the output to 0 V DC with no input.

Thanku sir

There's no capacitor in Q2 after 10k resistance, so how to ground ?????

1:40 This circuit has quite a few design flaws. The input stage has a very low bias current of abt. 1.7mA, leading to low transconductance and current starving of the voltage amplifier stage at frequencies above 1kHz, which in turn causes poor slew rate and distortion (mostly 2nd harmonic). It's also hugely disbalanced, because one transistor draws abt. 0.46mA (0.7V/1.5k), while the other one draws 1.7-0.46 = 1.24mA. The whole point of a differential pair is to be perfectly balanced. Deviations in transistor currents over 1% cause a significant increase in distortion (2nd and 3rd harmonic). The best solution here would be to use a current mirror - the increase in complexity and cost is negligible compared to the great improvement it makes. It's also beneficial to increase the bias current to abt. 6mA and add emitter degeneration resistors of abt. 33 Ohm to the differential pair. The dominant pole capacitor (220p) is too big. The whole point of the dominant pole compensation is to bring the open-loop gain down to unity just before the phase shift at the output approaches 180 degrees, thus turning an amplifier into an oscillator. The value of Cdom is determined by the current sourcing/sinking capabilities of the transconductance stage and the VAS collector impedance. The open-loop gain here is not that high to begin with, due to the aforementioned low transconductance and current starving of VAS. All of this leads to a poor slew rate and great increase in distortion at higher frequencies. The VAS collector is loaded by a current sink, which is correct, but there is never a need to adjust the exact current flowing through it, so the 10k potentiometer is useless. The 2.24k pot is placed between the Vbe multiplier's base and collector, which is a timebomb, because if it fails, the bias voltage will increase to a maximum, likely causing the output transistors to blow up. It's always a better idea to put it between the base and the emitter. The 3K resistor between the driver transistors' emitters is too big. Reduce it by a factor of ten and put a 0.1-1uF capacitor in parallel. Its purpose is to provide a small reverse-bias voltage to the output transistors, making them turn off faster. Doesn't hugely matter in this relatively low-power circuit. It's always a good idea to couple the lower leg resistor of the feedback circuit (10K) to ground through a large (470uF+) capacitor, thus bringing the DC gain down to unity. The input pair is never going to be perfectly matched, and you don't need to amplify the DC offset voltage. The 220K will then have to be reduced to the same value as the input bias resistor (10K in this case) to match the impedances. It's always better to keep the value of these resistors as low as practically possible to reduce the Johnson noise (the exact values will ultimately depend of the signal source's output impedance). It's also necessary to put a small (4.7-33pF) capacitor in parallel with the upper leg resistor of the feedback circuit. This circuit is likely to work fine without it because its dominant pole frequency and slew rate are very low and therefore the Nyquist stability is not compromised - but the noise and distortion figures most definitely are. That's all. :)

We are still waiting on part 3!!

You can substitute the Darlington output configuration by a Sziklai output configuration in order to get a little more output voltage swing and output power. Probably you can also use the D44VH10 / D45VH10 as single output transistor combination. They have a very high current gain (> 200 @ 1A, > 100 @ 4 A) which should be enough without current gain multiplication. The collctor base capacitor at the transistor of the voltage amplification stage appers to me a bit too large. I would recomment not to exceed 47 pF. Otherwise the amplifier could become too slowly for a sufficient pulse response. Further options are a snubber network at the amplifier output to compensate for wire / spreaker inductances and an input low pass filter (1 kOhm, 1 nF) to avaid rf input penetration.

Hi ...can you do schematic?

How would you calculate or determine the gain and input resistance of the pre amplifier transistor?

At the beginning you are missing the input voltage or level specification.

Hi.a question what is difference between video and audio amplifier pls answer me if you know

do you have a gerber about this desing?

And an $8 I.c. does it with 10 times less distortion...

and how to finde amplifier watt

sir pls explain op amp and amplifier part stages

Are you sure about this feedback loop between the power output and base of the "right" transistor in coupled pair ? I mean - if you had a capacitor in series with this 10k resistor then there would be nothing wrong but if you dont have it then the voltage on the power output in bias state will be highier equivalently to the proportion of the resistances of the feedback divider because its connected to the ground. And I assume we want to stabilize the bias voltage having the ground as reference because the "left" transistor of the coupled pair is biased through 10k resistor to ground without any divider. That's little yet tremendously important detail - if missed it will cause disstorsions or in the worst case it's gonna blow up the power stage because the output transistors will be "trying" to put at least several volts above ground on the few ohm resistor which is the speaker in bias state - thats a lot of current. Details of this kind are CRUCIAL for designing even the crudest and most basic power amplifiers.

Stop putting sub tittles ,that is bidding what u r trying to show on book

Your dome is pushed-in. Not serious about the business.

can you help me give my opinion about my circuit? Can we exchange gmail?

Use a TDA2040 and save yourself design headaches.