Say you record your guitar dry on channel one, disarm channel one so you don't record over it and send that channels' output to your effect. The output from your effect should be connected to a seperate channel on your recorder which is armed. Watch your levels & ensure you don't make a mistake and create a continous loop or you could overload your machine & mabye do some damage plus get horrible feedback!! In my setup instruments are recorded completely dry, the signals feeding the tape machine are fed from my mixers' inserts. My tape outs are then returned to the mixer inserts where they are fed through eq etc with the option of sending to my effects on my mixers' auxilliary send & return section. I then can connect my fx out directly into the tape machine if I'm happy with the sound (I guess the proper way of doing things would be to assign the fx return to a seperate stereo bus which is connected to the recorder - don't know I only have one real stereo bus) I don't always do things this way but it does mean that you can fiddle with the sound a bit more to your liking without having to constantly re-record. I guess this is how most people set their studio up but I'm an analog newbie with no books or guides so cannot confirm this.
