Power supply help

[fikri]

Hi ! I need some advice to build  a power supply for my preamp. Basicly i have to power some filaments (2x 12ax7) and my tonemender. And also one relay for channel switching. My power transformer is rated 12V 2A. Right now Im looking for a LM317 based regulator for powering the whole unit (filaments, tonemender and relay) is it suitable ? or i have to use 7812 regulator and to provide the rectifier for each section ? Thanks

[brett]

Hi
Are you using 6.3 V or 12.6 V on the heaters?
At 6.3 V, you'll be drawing 600mA or more for 2 AX7s, which will stress and may exceed the power rating of a single LM317. 
Far better to keep the current low, so I suggest wiring the heaters in series (for 12.6 V, 300mA), and use an LM7812. 2V x 0.3A = 0.6W, which should be easy for an LM7812.
The output of an LM7812 is just enough volts to feed an LM7809 for any 9V effects.
cheers

[fikri]

Hello brett, I'm powering the fillaments with 12V. The max rating for the LM317 is 1.5A is it true ? can i just powering my tonemender with 12V directly ? And how much a relay can draw current ? Thanks