There are approximately 19,372.3 different ways to use effects within a guitar rig. You can use inbuilt amp effects like tremolo and reverb. External pedals like wah-wahs and overdrives. Little units that actually plug directly into your guitar. Effects racks. Multi-effect floorboards. Even an iPad can be used inline with the rest of your gear to provide effects or even synth sounds. But there's one particular method which is preferred by many pro players, yet it's relatively unknown and definitely under-utilized by the average shredder in the street: the 'Wet-Dry-Wet' rig.
Put simply, this is a rig using one unaffected mono signal along with a stereo effect chain feeding its own speakers. The idea is that your spatial effects like delay and reverb, (and sometimes modulation effects like chorus and flanger) can live in their own stereo rig while the unaffected guitar gets its own speaker. Aside from adding quite literally three-dimensional depth to your tone, it also gives you unprecedented clarity because the effects aren't all being crammed through a single amplifier and competing with the dry sound. This is especially a concern with effects like delay and reverb, where their detail can be smeared and mushed up in a mono rig.
There are lots of ways to accomplish this, and the pros often do so with elaborate buffered, power-conditioned, mega-thousand-dollar-costing rigs. If you have the budget, go nuts! A common way to do it is to plug your guitar into your amp, send the amp signal to a splitter/dummy load and into separate power amps - one for the dry guitar feeding a 'dry only' speaker cabinet, and another into a stereo effect unit or ten, then into a stereo power amp to drive the 'wet' speakers.
There's a much cheaper way which may not give you quite the fidelity of a full pro-assembled rig but it'll get you pretty close: a stereo combo amp with a stereo effects loop. There are plenty of these on the market, especially used solid state or hybrid tube/solid state amps from the ‘90s. And it's not much different to using a regular effect loop. Just plug a cable into your main amp's effect send, hook up some stereo effects, then send the outputs of the last effect into the effect return of the stereo combo. Your dry sound will continue to be sent through your regular amp but the effects will go through the combo. You may or may not need a ground loop eliminator if you happen to get some hum, and it's a good idea to use a filtered power supply for your effects. But once you've laid the ground work this can be a very effective technique.
A few tips:
* Use a delay that allows you to turn the dry sound all the way down. That way you won't get weird phase cancellation issues between the dry and effect speakers.
* Some effects should remain a part of your dry amp's signal chain: overdrive, fuzz, distortion, tremolo, wah-wah and octave pedals are particularly suited to being a part of your main sound rather than a parallel effect.
* Some effects like phasers and flangers will be more pronounced when used in a wet-dry-wet rig because their swooshy character will contrast with the dry sound.
* You can even get creative with the stereo signal chain and use one speaker for delay and the other for reverb. Or, for a classic ‘80s hard rock delay sound, try two or three slapback repeats at around 40ms delay time in one speaker and a couple of longer repeats in eighth notes in the other speaker.
* Most harmonizers give you the ability to send separate harmonies to different outputs.
* If chorus makes you feel a little queasy through a wet-dry-wet rig, try the Eddie Van Halen trick of using a stereo pitch shift effect (harmonizers are capable of this) with one voice shifted just a few cents higher than the dry note, and the other voice set just a bit lower. You'll get a broad, rich multi-voice sound that doesn't waver in the way the chorus does.
* Take advantage of stereo pan effects and subtle tremolo!
* Use an expression or volume pedal to fade the effects signal in and out as needed. This can really add drama to a solo or a particular part of a song.
The only real problem with running a wet-dry-wet amp rig is that it can be hard to back to a regular mono effects setup!