Has anybody tried this?

[David]

Has anybody tried adding the "auto noise filter" thing to a power supply like Jack Orman documented in his Lab Notebook?  I'm curious to see how it turned out.  I will eventually build a squeaky-clean power supply from the ground up, but in the meantime it would be cool if adding this coil thing would give me a quick fix.

I found out something, though:  I don't know if this applies to all Rat Shacks, but the one where I bought the device was having a closeout on them, and they weren't planning to restock.

Another thing:  I ran through my plan with someone at the office with a fair grasp of electronics.  He said something about this noise filter that concerned me.  He believes that when the power supply transformer is turned off, the coil will dump what it has stored into the circuit(s) hooked up to it.  That doesn't exactly reassure me.  Does anyone have any knowledge of this?

[niftydog]

he is technically correct, although I have no experience with these filters so I don't know how much of a problem the inductive kick is.

You can put a diode in to shunt the high voltage to ground... but...

There's better ways to filter noisy power supplies, what exactly is the problem?

[David]

There's not really a problem.  I have a power supply made from a rescued wall-wart.  It's got the diode bridge and the filter capacitor.  It also seems to put out 9V without a problem.  I'm using it with a DIY fuzz and 2 DOD pedals.  The DODs seem to be handling it OK.  The fuzz hums.  I was just looking for a simple way to stabilize the existing power supply because the voltage seems to be locked.

[niftydog]

what do you mean by "locked"?

I would consider opening up that DIY fuzz and jamming as big a cap as you can fit accross the power supply inputs. Big cap = less ripple could result in less hum.

Either that, or upgrade the cap in the wall wart.