spring cleaning for my signal path

[dagosto]

Originally Posted by Nubus

Voltage is a potential difference. It isn't just the measure of amplitude... there isn't any amplitude unless current is allowed to flow.

Think of the pendulum on an old grandfather clock. The pendulum swings between points A (all the way to the left) and B (all the way to the right). The distance from equilibrium to either A or B is amplitude and; in this analogy, can be thought of as the voltage. Without power to the clock that voltage is still there as the potential difference, but since there is no current the amplitude is zero.

I don't really get what you are saying. Your example of voltage without current is a little like describing pressure without air particles. Simply by taking a look at ohms law:

V=IZ

where Z is constant, there is no voltage across a circuit if I = 0. Sure there is still voltage in the wall socket and if you looked at it you woulkd see half of a 60Hz square wave from each lead. In this state it is just potential energy. Once the current is allowed to pass through it becomes kinetic and the voltage is analogous to the amplitude of the signal.

My point is that when you are measuring the amplitude of an electrical wave on an oscilloscope you measure the peak to peak amplitude in volts. Constructive or destructive interference may not in theory be adding or subtracting volts but the measurment of voltage graphed against time is an analogous representation of the change in amplitude due to an interfearing signal just the same.

[Nubus]

That clock analogy i dreamt up doesn't really make sense until you think of it as potential energy, and plugging into the formula makes V=0 but what if your impedance is infinity. I guess then in theory it does not exist until it is given a place to go. But the way I thought of electricity was as the possibilty for current to leap across a voltage and try to get to earth as quick as possible. Am I wrong?
If you hear harmonic distortion in a piece of gear obviously it is a voltage, but I wouldn't know how to determine that voltage. I also think what you are saying about the addition of harmonics increasing amplitude and pushing the sound into nonlinearity totally happens all the time, I mean that is what we love about driving tubes. But it isn't always appropriate...

[dagosto]

Originally Posted by Nubus

That clock analogy i dreamt up doesn't really make sense until you think of it as potential energy, and plugging into the formula makes V=0 but what if your impedance is infinity.

Ohm's Law only applies to a closed circuit. Infinite impedance is effectively an open switch, or more accurately a perfect insulator.