Line level signal vs. Instrument signal, the difference? Options

[jeremija]

Can somebody tell me (or point at somewhere to read about) what is the main difference between the line level signals and instrument level signals?

Also, what should be the output impedance of line level signals generators and instrument signal generators?

All I know for now that the line level signals have a maximum voltage of 2 V peak to peak, and that guitar amplifiers usually have the input impedance around 1Mohm (because the pickups have the impedance at around 250÷500kohm). Does this 1M refer to the impedance that is measured with a test constant voltage of a single frequency which has the biggest current Z = U(f) / I(f) ?

I'm considering building a device which will transform the signal from my sound card sand send it to a guitar amplifier's input (something like a re-amp box). I have found a scheme here, but I would like to know more about the requirements of such device (what should be the input impedance, output impedance, output max voltage and such...)

This post has been edited by jeremija: Feb 17 2010, 10:38