Filtering suggestions for 500ma DC wall wart

[goldstache]

Built a great submini preamp that is dead quiet when using a bench top pwr supply.  Need to implement filtering in circuit for quiet operation with off the shelf wall warts. 
Here's my block diagram:
12vdc(17vdc unloaded) > 12vdc regulator with 100uF filter to gnd > filaments and SMPS.
Any suggestions?

[R.G.]

Can't really tell how much is enough without knowing the currents involved.

Failing knowing the currents, put a 1000uF/25V cap in front of the 12V regulator, and put a 0.1uF monolithic ceramic across it and also across the output of the regulator.

Do not forget reverse protection diodes from output to input across the regulator and from ground to output across the regulator output.

With nominally "12V" wall wart, if the current gets too large, the output will sag below the 14V that a normal 7812 regulator needs to regulate, so the thing will only stay regulated in the lower roughly half of the wall wart's stated current range.

[goldstache]

Firstly R.G., thanks on behalf of everyone here!  And congrats on 15,000 Posts!!!!!!!!  You've taken time to help me a lot, along my path to "grasp"! 

Regarding my project:

Current info on hand:
Two 6021 subminis, filaments of tubes wired in series (12VDC)-300ma
Loaded with SMPS for plates-480ma total draw of circuit (or at least my regulated variable bench top PWR Sup. is saying so!!!??)

So your comments are spot on.  It's a 12VDC 500ma wall wart that was giving me the hummmmm!!!
I have to delve deeper into the actual draw of the SMPS to understand exactly what the plates are drawing.  But there is apparently about 200ma to accommodate for after filament draw. 
I will try with a 12VDC 1amp wall wart I have, that Im pretty sure has minimal filtering built in. See if avoiding the Sag will help with noise floor!
Thanks again I will post progress!