tda2040 audio amplifier circuit

[lignin]

hello forum.
ı want to build a audio amplifier circuit. And ı built this circuit. But output power is reasonable at 20 hz or 2 khz or 10 khz. ( minimum value of output power is 5w) but other high frequencies such as 15khz ,20 khz , the output power is not reasonable.

what can ı do for high frequencies.

here is circuit :

 

[FvM]

output power is reasonable at 20 hz or 2 khz or 10 khz. ( minimum value of output power is 5w) but other high frequencies such as 15khz ,20 khz , the output power is not reasonable.

Means exactly what? Are you reporting simulation or measurement results. How did you determine "output power"?

 

[chuckey]

if you are talking about gain, make C8 smaller, it provides a HF roll off and might be causing youe effect.
Frank

 

[FvM]

If the schematic is correct, C8 gives 3 dB attenuation above 800 Hz. Nothing that can be related to the original post.

 

[Audioguru]

The low frequency gain is extremely high at 211 times which reduces negative feedback and increases distortion. The circuit in the datasheet has a gain of 33.3 times.

I agree that C8 and R6 cut high frequencies above 800Hz but by only -3dB. Remove them and reduce the gain.

 

[lignin]

sorry about my english
here is my simulation measurement.

this circuit have to work properly between 20 hz and 20khz.
output power have to be minumum 5 w

20 Hz simulation measurement : output power is 25.5 w
2 kHz simulation measurement : output power is 23.71w
20 khz simulation measurement : output power is 1.21 w (ı have to increase this power)


ı tried with smalled C8 but it gave same results.

 

[FvM]

The low frequency gain is extremely high at 211 times which reduces negative feedback and increases distortion. The circuit in the datasheet has a gain of 33.3 times.

Yes, that's surely no good idea. But according to the TDA2040 datasheet, the bandwidth should be still around 50 kHz. Thus I think it's an incorrect simulation model.

 

[Audioguru]

Why bother using a simulation program that is WRONG?
Instead, build the circuit and measure it.