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Yes, that is the general configuration for a split power supply.
But you may not need a regulated supply for a power amplifier, although it should improve the distortion characteristics somewhat.
And the power supply voltage you need depends upon the amplifier rating and how much power you want from the amplifier. For example, a typical bridge-output audio amp will probably have a low-distortion output of about 24V peak into an 8Ω speaker load with a ±15V supply. That would give a maximum power out of 35W.
you won't want the regulators, as you want to have more current available for output stages. the supply you've shown is normally used for the op amps in preamp stages. with +/-15V supplies, expect an amp to put out about 10Wrms, and require peak currents around 2A (which 7815 regulators cannot do, as most of them are 1A regulators, and 1 or 2 manufacturers rate them at 1.5A)
Please tell me which one is more trustable and a better regulator chip? LM317 or 78XX? I do know that LM317 is an Adjustable regualtor, but want to know if it's efficiencies are like 78XX?
From a technical point of view, the LM317 is the better choice but the LM78xx is more convenient. Don't forget that if you don't want a variable regulator, you can always replace the variable resistor with a fixed resistor.
Another question which Comes up:
I have down the above configuration for two L7808CV & L7908CV. the input voltage comes from a 2x24 RMS transformer rectified with a full wave rectifier.
The problem is that the positive/ negative output voltage drops from 16V to almost 7.5 to 8V after a few seconds???!
There's nothing unusual about that, the two different ICs will shut down at a slightly different current or temperature. The protection circuitry tolerances are very wide.
Your regulator chips are shutting down because they are massively overheating - you're feeding them for a MUCH too high a voltage?. They are probably shutting down too fast for them to feel hot.
As Hero999 mentioned, it's also VERY possible that you're exceeding their maximum input voltage.
I face an strange problem which seems to be the main reason of the said problem.
the output rectified have an strange behaviuor. The voltage of the positive lead reduces gradually while the voltage of the negative lead increases gradually. the voltage of the negative lead access to more than 50V after 5 to 6 seconds while the voltage of the positive lead droops to almost 10V. very strange?!!!!!
Yes, the power dissipation is 2.6W which might be enough to heat the die to a high enough temperature to shut down before the tab gets too hot to touch, there again I suspect some other protection circuit might be kicking in due to the high voltage.
No I didnt.
I measured the outputs before connecting them.
Please be aware that the voltages do the said strange behaviour gradually, that means the output voltages are OK for the first second.
Yes, the power dissipation is 2.6W which might be enough to heat the die to a high enough temperature to shut down before the tab gets too hot to touch, there again I suspect some other protection circuit might be kicking in due to the high voltage.
are you using a center tapped transformer, and is the center tap grounded? if not, your ground reference will drift. that could be the cause of your drifting voltages.
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