Coincidence.Also AudioGuru, looking at the fact that the amp has 4 X TDA7296 each capable of handling a max of 5 ampere which brings a total of 20A peak.
Now the transformer is rated 150.9 --> 20.1V X 2, 3.75A
Dividing the system current to the four TDA7296 = 3.75/4 = 0.94A for each TDA.
Also voltage applied to each TDA7296 = +/-20.1 = 40.2V
Since Watt = Volts X Ampere
= 40.2 X 0.94A
= 37.79 = 38W
This exactly matches with what you said "TDA7296 produces 38W @ 0.5% THD @ 26 VDC".
What is your say on this?
1) The transformer has its current rated in AC amps but the amplifier operates from DC amps.
2) The rectifiers produce peak voltage that is filtered. The peak voltage is 1.414 times higher than the RMS AC voltage and the power cannot be changed so the DC current rating is 0.707 times the AC current rating.
3) You need to calculate the RMS DC current not guess at the peak DC current.
If the transformer was more powerful then the woofer gets 120W and each satellite gets 38W for a total of 196W. At 70% efficiency the total power required is 280W. Then the RMS current in the 40.2V transformer is 280/40.2= 6.07A.
But nobody plays their sound system at full blast all the time except you at your house party. (smilie)
The sound system in my car has a total continuous output of 288W RMS. I have played it very loud but I have never heard it clipping. It has a real sub-woofer that might be clipping a little but it and the rear seat filter out the distortion harmonics then I don't hear the clipping distortion.
My home stereo has a total continuous output of 140W RMS and I have had it loud enough to clip more than a few times. My dog runs away.
I live in a brick home, not a cloth tent so it doesn't bother the neighbours.