Questions about musical gear levels

[CaveMike]

I'd like to do some home recording of my guitar and mic. I have various pieces of gear and I am wondering what my options are for interconnecting the components.

This (http://en.wikipedia.org/wiki/Line_level) wiki page explains the differences between:
instrument/mic level line level headphone/loudspeaker levelRoughly speaking instrument/mic level runs through a preamp to get to line level which then runs through an amp to get to headphone/loudspeaker level. I've got this. I also understand that the differences between the levels are both voltage and impedance.

One question I have is what does a typical stomp box output? For example, I have this (http://www.bossus.com/gear/productdetails.php?ProductId=126) Boss pedal. The specs indicate the output is -20 dBu. This is instrument level right? I've noticed that I can hook the stomp box output into my mixer's line level input and get some sound provided I crank up the stomp box's level. Will this corrupt the audio signal or is this an acceptable solution?

I also have a multi-effects processor with a stereo headphone output. I know this is a hotter signal than line level, but is it acceptable to connect this to my mixer's line level input?

I'm not really interested so much in understanding if these things 'will work'. I certainly can (and have) tried them out. But I would like to understand if I am doing something that is affecting my audio signal -- affecting the frequency response, adding distortion, adding noise, etc.

Finally, as I have mentioned, I have an 8-channel mixer that takes line level inputs (Peavey Line Mix 8). What should I use to get my guitar and mic to line level so that I can feed it into the mixer? Some sort of preamp? In college I built an op-amp circuit to convert from instrument level to line level. Perhaps this is all I need.

As a side-note, I am thinking about getting an audio interface like this (http://pro-audio.musiciansfriend.com/product/PreSonus-FIREBOX-24bit96kHz-FireWire-Recording-System?sku=184133). This obviously will solve all of my problems, but I would still like to understand the gear that I already have.

Thanks in advance; I appreciate all of the help.

[BigT]

Practically everyone I know connects their guitar to the pedal to the preamp to the board. Still, the only problem I could think you'd have with audio quality with the way you have it set up would be the fact that you have to crank your pedal so high that you might be adding distortion.

As for multi-effects processor, I have to admit I don't have a clue. Borrow a pre-amp and see if you hear a significant difference between the two. (volume doesn't count). I know a church which merely plug the headphone jack of their iPod straight into the board. But, of course, that isn't for recording purposes.

[sleestak]

On the recording side I do have a suggestion about the audio interface. If you are going to buy one I highly suggest you get a DigiDesign MBox. They have multiple models. The cheapest seems to be this (http://www.sweetwater.com/store/detail/MBox2Mini/). I have a regular MBox and love it. It comes with ProTools LE, which rocks. Mine came with Ableton Live which also rocks. The MBox came with a bunch of great plugins and there are tons of awesome plugins you can purchase later (Sample Tank is my favorite, use it constantly).

I am planning on moving up to a DigiDesign 003 sooner or later.

Slee

[WordMan]

See? This is why I made sure my drummer is also a record producer - and a complete gearhead.

I don't understand any of that stuff. I barely can keep straight that I have to use different cable types to connect my amp head to the cab than I use to connect my guitar to my amp...

[CaveMike]

Thanks guys. I think I got everything sorted out. Like WordMan I never bothered to figure this stuff out which is a little embarrassing considering how long I have been playing and the fact that I have degree in engineering.

I have one new question though. My amp has a pre-amp output and a power-amp input. I've been using the pre-amp out as a line-feed to my mixer. And leaving the power-amp input empty. It works fine. However, the amp really heats up. By that I mean the metal portions of the amp get physically hot. Much hotter than they do when I using the amp normally (and at the same levels).

Does anyone know why this is? Does it have something to do with the fact that the power-amp input is empty? And thus the circuit is not complete? Or is it possible this is just additional heat from driving the amp harder than it usually is driven (both the speakers and pre-amp output are being driven).