WARNING: I am laying out all of my ignorance below and asking every question that came to mind in writing this. It will be a bit like drinking from a firehose, but please bear with me and answer if you're willing.

I've been reading up on impedance a bit lately and have several questions:

  • I think that you need a DI box for acoustic guitar (or electric) to bring it from instrument (IIRC, -60dB -- is that right?) to line level (-10 dB), but I have heard that it is possible to plug a bass directly into the snake and get sound out through the monitors/mains. Why is this? Is a bass signal a different impedance? Does it have to do with active pickups? Isn't there a preamp in most acoustic guitars anyway? Shouldn't this put the output at line level? How does a DI box work anyway? Why are electric guitars so quiet when you put them through a DI box? I've tried it before just to see, but the results blew.
  • If mics are also at a similar level to instrument pickups (http://en.wikipedia.org/wiki/Line_le..._signal_paths), why can they plug into a snake directly without a DI box? Don't they usually get routed through a preamp? Why don't guitars get the same path?
  • Could you, in theory, go from a guitar to a single stompbox to a snake and still get a reasonable level of signal into the board? I always thought the output of most pedals was a line level signal, so it effectively acts as your preamp.
  • I've read that headphones generally have lower impedance than line level. Is there a reason why you can't go guitar into a stompbox into headphones? Your pedal would always be engaged, but shouldn't it work? I figure if your voltage is the same, the lower impedance would mean more current, right (V=IR)? I've never tried it, but am wondering if it would work.
  • If you were to do something like what's listed above, what's the appropriate headphone impedance? My Sennheiser HD201 are 24 @ 1 kHz, which I think is pretty low for headphones.
  • What is the difference between the amp/mixer outs on something like a Digitech Bad Monkey? Does one have power amp/cab sim on something as simple as a $50 OD pedal?