Require advise on tda2050 this schematic

[J.Hoyer]

TDA2050 single supply

Hello, first I want to say thanks to all diyaudio forum members. The place is incredible, mecca for audio enthusiasts all over the world.

Heres my question about TDA2050 gainclone. I have designed a circuit and now before I start constructing I ask you to check it for errors and weak points. It is basicly a single supply schematic from TDA2050 datasheet that I have modified according to Rod Elliott's Project 72 Single Chip 25W Amplifier (Project 72). I have added the RF filter in the input and modified the Zobel circuit values.

1) are my modifications OK?
2) is there any real benefit from having "low ESR" caps in this schematic?

Circuit:

 

[AndrewT]

The section title is "Chip Amps", not gainclones.

C3+C10 is too big in comparison to C5.

 

[J.Hoyer]

C3+C10 is too big in comparison to C5.

So do I have to make input, feedback and output cutoff frequencies more equal?

 

[AndrewT]

C5 must be selected such that virtually no DC voltage and no AC voltage appears across it irrespective of what frequency the operating amplifier is asked to process.

 

[J.Hoyer]

I modified the circuit:

input cutoff frequency (2uF 24k2): 3.29 Hz
feedback cutoff frequency (47uF 680R): 4.98 Hz
output cutoff frequency (6000uF 4R): 6.63 Hz

What do you think about charging output caps through headphone circuitry when turn on?

Do yuo see any weak points in the circuit?


PS! Single supply solution was selected this time because I had the transformer, I want to study the solution and see its performance. Speaker protection into the bargain.

Thanks!

 

[AndrewT]

JH,
you have the frequency back to front.
The single pole passive input filter should determine the passband of the amplifier. That should also include the Rf filter as well as the DC blocker.

 

[J.Hoyer]

JH,
you have the frequency back to front.
The single pole passive input filter should determine the passband of the amplifier. That should also include the Rf filter as well as the DC blocker.

So the input side filtering should be the bottleneck?

 

[AndrewT]

set the passband of the amplifier at the input, i.e. both low pass and high pass.

 

[csom]

Hi all
Is there any "burn-in" time for TDA2050 amp?
If yes what is the typical burn-in time of this IC ?

I am curious to know because I found the sound has got slightly better after some 24 hours of running time of new amp.

I might be wrong, I'm afraid. So I just want to confirm from other experienced members whether I am right or not.

Best regards,
Som.

 

[AndrewT]

about the same time as it takes for the speaker delay circuit to connect the speaker.

 

[JMFahey]

"Burn in time" *often* refers to the time *you* need to get used to the amp or speakers.
And I'm not joking.

 

[csom]

Thank you Andrew and JMFahey