You can choose to use any effects unit you can afford - as long as the unit has an in and an out. With your Tascam - you likely have two options:
1. Use the effects send/retun - this allows you to take a "dry" sound already recorded on a "track" and send that sound to the effects unit and then return the processed sound to the recorder.
Most engineers prefer to track a dry sound and add effects (via send/return). The advantage to this method is that you can decide how much you want to effect the sound later in the recording process and you can adjust the processing as you go along). The disadvantage - if you only have one effects send/return - you have to alpply the same processing to whatever tracks you choose (you only have access to one effect)
2. Send the sound to an effects unit first and then send the processed sound to the recorder - this then records the sound....with effects (this is called tracking with effects) or "wet". This is the same as plugging a guitar into an effects unit and then plugging the effects unit into a guitar amp.
The advantage - you can assign a different effect to each track as you record (delay to guitar, revebr to vocals, etc). The disadvantage - once you've tracked (recorded) the sound with effects.....you're committed. If you later decide you don't like the effect......the only way to undo it, is to record the part over again.
