High power audio amplifier design

[mr_byte31]

Hi all
I am designing now my audio amplifier my self but need some help and ur idea
I have attached my design
my idea is as follows
the opamp will be used to solve the problem of distortion of the transistors
the transistors will delliver power to the horn
I can add parallel transistors to npn and pnp so the current will be divided on them

my problems
1- I want to know the effect of noise on this circuit?"from supply"
2- does it give high quality?
3- I don't know two identical transistors that can deliver much current to the speaker?
4- should i use mosfet instead of BJT??


I hope to know ur idea and how to solve those problems

 

[Audioguru]

The output power is limited by the max allowed supply voltage of the opamp which is about 36V so the max output power into 8 ohms is only 14 Watts.

The transistors are not biased so they have severe and horrible crossover distortion.

The amplifier has no voltage gain so it is useless.

A horn speaker is efficient but sounds awful.

 

[mr_byte31]

for a supply +V=36 and -v=-36
for R=8 ohm
I=36/8=4.5
I2=4.5*4.5=20.5
power=I2*R=20.5*8=162watt
I think this is a vey good power

"The transistors are not biased so they have severe and horrible crossover distortion. "
I don't need to bias them
the differential opamp solve the problem of biasing

I know that i need an amplification stage before the opamp
what i need is to resolve the circuit i uploaded

am I right??

pic is updated

 

[Audioguru]

for a supply +V=36 and -v=-36

No.
The max allowed supply for the LM741C is plus and minus 18V.

for R=8 ohm
I=36/8=4.5

No.
The max output voltage from the amplifier is about 15V peak.
The peak current into 8 ohms is 15V/8= 1.9A.

I2=4.5*4.5=20.5
power=I2*R=20.5*8=162watt
I think this is a very good power

No.
The RMS current into 8 ohms is 1.33A.
The RMS power into 8 ohms is 1.33 x 1.33 x 8= 14.2W.
It is not much power.

"The transistors are not biased so they have severe and horrible crossover distortion. "
I don't need to bias them
the differential opamp solve the problem of biasing

No.
The lousy old 741 opamp is too slow to reduce the horrible crossover distortion. It has trouble above only 9kHz. Even with a fast opamp the crossover distortion will sound bad.

 

[mr_byte31]

I wish I could find a simple effecient circuit

 

[kwkam]

Goto buy LM3886 kit is more simple and efficient

 

[Audioguru]

There are thousands of excellent class AB amplifier circuits on the internet with plenty of output power and almost no distortion.

Don't use a lousy old 741 opamp for audio. It is 42 years old and things have changed and improved over the years.

 

[snafflekid]

Don't reinvent the wheel. You can find something suitable in a single chip. Are you experimenting?

 

[mr_byte31]

No I am not expermenting
the problem is there is no LM3886 IC in my market
I found TDA2030 but i found it can deliver 45W maximum

 

[FvM]

There are also audio amplifier circuits up to many 100 W power on the net, only using discrete transistors.

Seek and you will find. [Mt 7:7; Lk 11:9; NIV]

 

[mr_byte31]

yes I can find many but the problem is the quality
I couldnot found easy cheap one with good quality

 

[Audioguru]

Wait 50 years when your country catches up with technology in our parts of the world.
Or move and live in a civilized country.

 

[mr_byte31]

silly joking