Strange Power SUpply Problems...

[sjaltenb]

Ok so I just build all my power supplies for my MultiFX board. They are standard 7809 power supplies, and they are putting out exactly 9.02VDC

My wiring is as follows:

Transformer Secondaries-->Power Supply Input-->9VDC+ to 9vDC input on FX
The ground for the effect goes to the power supply ground, and a wire connects the power supply ground to the signal ground, so, in theory this is just as a power supply would in a normal setup.

This worked Perfectly when I tested it earlier. Now, when I do this, the signal goes completely silent. What REALLY confuses me is that the power supplies are all working (I also put a status LED in there) even when there are NO grounds connected to the supply on either end!

On each supply i placed a "battery in" plug, and when I plug a 9v battery in, and connect everything identically, the effects work perfectly.

I cannot grasp what would be any different, the effects are getting 9.02VDC, the grounding scheme works perfeclty with a battery, but when I do it using the power supply the sound goes completely silent, as if the signal were going to ground. If i remove the ground, i get a ton of crazy noise.

(Note, i use the term Ground loosely...I know that I am not using it properly)

THanks!!!

[sjaltenb]

i'll be damned if i didnt unplug it, move it 3 feet and plug it back in and it works. in fact, i cant get it to not work.

wierd....but damn is it awesome!!!!!

[MohiZ]

It could be a bad connection somewhere. I'm glad you got it working, but be prepared the problem will come back 

[Auke Haarsma]

Yeah, sounds like a risk to me. If something suddenly stops working and then suddenly works again.... you can't rely on that.

[R.G.]

Ghosts.

Demons. The power supply is possessed.

Poultergeists have been moving your wires.

Maxwell's Demon is being uncooperative.

Mother Nature is offended.

[Cliff Schecht]

Perhaps his copper magnet wire was mined from an ancient burial ground.

[sjaltenb]

 

I really don't know what happend.....of course it was late and I may have just been missing something the first time around. But it continues to work perfectly no matter what I do. So...who knows. Only continued testing will tell the truth. I'm guessing I was just missing something the first time around..

On another note...

I have heard my transformer "Click" at times. noise coming from the ACTUAL thing, not in the signal or from the amp. It seems like it kinda clicks or hums for a few seconds, then goes away. Is this a concern? Doesn't seem to do it very much, and it is barely audible. Keep in mind its a BIG hunk of iron.