I own an ADL Esprit pre amp which uses a 15V wall wart power supply. The pre amp ocassionally "drops out" which I think is due to the wall wart supplying <15V to the L7812 voltage regulator in the pre amp.
I have thought about buying a 15V linear supply to replace the wall wart which would supply the L7812 with a "clean" and stable 15V.
I then thought perhaps it would be better to buy a 12V linear supply, get my soldering iron out and bypass/remove the L7812 regulator.
What do the all the people here with power supply experience think?
1) is it better to have double regulation, 15V linear supply followed by L7812 regulator
or
2) just use a "good" 12V power supply
I have thought about buying a 15V linear supply to replace the wall wart which would supply the L7812 with a "clean" and stable 15V.
I then thought perhaps it would be better to buy a 12V linear supply, get my soldering iron out and bypass/remove the L7812 regulator.
What do the all the people here with power supply experience think?
1) is it better to have double regulation, 15V linear supply followed by L7812 regulator
or
2) just use a "good" 12V power supply
Option 2. The 7812 is easily beaten by a LM317 which in turn is easily beaten by a well-made TL431-based regulator. This is even before you get to the exotic parts. The 7812 needs about 3V headroom so the 15V seems a little marginal. Even a 7815 with a cap multiplier after it would be an excellent bet for removal of almost all PSU noise.
The part that I am undecided about is buying. I'm not sure what is available in your part of the world.
To your problem however, the preamp 'dropping out' can't be due to a small supply glitch. It's not possible to tell what causes it without some more description and a schematic, but if the input voltage drops by a volt then the 7812 will simply stop regulating and pass on a volt less to the output - this should not cause a circuit to stop working.
The part that I am undecided about is buying. I'm not sure what is available in your part of the world.
To your problem however, the preamp 'dropping out' can't be due to a small supply glitch. It's not possible to tell what causes it without some more description and a schematic, but if the input voltage drops by a volt then the 7812 will simply stop regulating and pass on a volt less to the output - this should not cause a circuit to stop working.
Any of the L78 series will stand up to 25volts supply. So, just use a higher voltage supply.
The pre amp does not require a dead smooth and noise free supply, so to use a different regulator is to me a folly.
The pre amp does not require a dead smooth and noise free supply, so to use a different regulator is to me a folly.
Why would it "drop out" from a little sag?
(The key digital bits are surely on 5V or 3V supply.)
Prove the fault before you start fixing.
