Linear power supply 15V, or 12V and bypass L7812

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
2) just use a "good" 12V power supply


Paid Member
2002-09-25 11:01 am
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.