DC regulator supply: filtering advice

[lopsided]

Hey guys,

as my pedal chains has grown with a 24V memory man and a 18V supreaux2 and even my 9V battery consumption is quit high I was thinking of building a regulator from the 24v/1a wall-wart I use for the memory man to power also the supreaux and maybe two or three 9V pedals.
I went through the power-supply articles at geofex and beavisaudio and through the 78xx datasheet and came up with this:


Now I am not sure how well I have pasted the ideas together so I would be really grateful for any comments on improving the filtering and so.

Thank you.

j.

[craigmillard]

Why the 7810, use a 7809 and get a regulated 9v for all your 9v pedals?

[ayayay!]

I'd probably go for the 10 volt too, to be honest.  Most Power Supplies put out 9.6 volts anyway, so it'd be easier to drop it the .4 volts (if even necessary.)  Most fresh batteries also test out about 10.3V.

[lopsided]

Most Power Supplies put out 9.6 volts anyway, so it'd be easier to drop it the .4 volts (if even necessary.)  Most fresh batteries also test out about 10.3V.

- exactly my thinking.

Just one question before I start putting it together: would it be wise to put a 100R in front of each regulator (when I have a 100R to filter the straight 24V line) or is this unnecessary?

[defaced]

100R in series will give you a source of voltage drop.  If you pull too much current through the regulator, the drop across the resistor will cause the regulator to fall out of regulation.  Assuming 1.5v for dropout, you're looking at 45ma on the 18v line and 125ma on the 10v lines.  The 100R in the 24v rail is most likely going to form a CRC filter with the last filter cap in the supplied 24v.  A CRC pi filter is pretty good, so having the 100R in there makes sense. 

[brett]

Hi
a single pole filter usually works well. Try an in-line resistor of 3.3 ohms followed by 1000uF of capacitance to ground. That takes care of hum. Now, run a 0.1uF film cap in parallel with the 1000uF. That'll absorb spikes and RFI.
If you are powered from a 40 year old generator at an outback sheep station under blinking flouro lights, use 2 filters in series. Really. 
cheers