my orban 642b eq hisses too much, fixable?

  • Thread starter Thread starter earworm
  • Start date Start date
dementedchord said:
went by the old shop and looked at the schemo... this one is'nt like i remember but it's still doable... trying to get someone to scan the schemo for me so i can send to you... there's a wire coming out of the expression pedal that should work fine... it's the white one...(assumming it's not been rewired)
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excellent! we're getting close. It has not been rewired as the original RCA type connectors are intact (and cracking a little bit).

Thanks :)
 
earworm said:
what does a capacitor do?
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Capacitor... it's like a balloon. No, hear me out. Imagine you have a pipe. That's a wire. You put an air-filled balloon in the middle of it. That's a capacitor.

Notice that no water can flow past the balloon. In much the same way, a capacitor blocks DC voltage.

Now imagine that the top of that pipe (above the balloon) is open. It is capped in such a way that the balloon can't jump out, but otherwise is open on top. That's like a ground. If the balloon weren't there, water would pour out on the ground. :)

So what happens when someone flushes a toilet near this balloon? The pressure in the pipe suddenly drops and the balloon expands a little to make up the difference, thus pushing the pressure back up a little bit. When the toilet stops, the pressure increases and the balloon contracts, absorbing some of the pressure. A capacitor between an AC source and ground tends to smooth out the AC signal in much the same way.

Finally, if you fasten the balloon over the top of the pipe so that the water fills it up, assuming the balloon is stiff enough to handle the pressure without exploding, it will build up to a point where the pressure in the balloon matches the pressure in the pipe and will stop expanding. What if this pipe can provide only a trickle of water, but at a high pressure? Say the balloon has two tubes in its mouth: a tiny tube connected to your water line and a large tube connected to the toilet.

The balloon will take a while to fill up, but will eventually be able to provide a large amount of water at the same pressure as the small tube is providing. If the toilet was designed to only handle that trickle of water provided by the small tube, when you flushed it, the toilet would likely explode. :)

That is like a capacitor between a power source and ground with no place for the power to go. The capacitor will charge up to the source voltage, but will be capable of dumping a large amount of current as soon as the stored power has a place to go. This is, if I understand correctly, roughly how camera flashes work, for example. A battery drives an inverter circuit to generate a high voltage at a relatively low current. The capacitor then stores this energy, eventually dumping it all at once, resulting in a high voltage with high current.

It's a slightly crude analogy, I know, but I think it illustrates the more important points of what a capacitor does.
 
this is the police.... put down the bong and step away.....
 
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