For years I staunchly held firm the belief that a beautiful tone should come solely from your amp. In my limited world-view stompbox overdrive or distortion was, at best, a hack. I felt that if you couldn't get the tone you wanted from your amp, you probably needed a new amp and no pedal was really going to make up for that deficiency.
But a few years ago I started questioning this belief. One reason was that getting all of my overdrive and grit from the amp limited my tonal possibilities. Sure, I still have volume and tone knobs as well as pickup selectors, but even then my choices still felt constrained. With a multi-channel amp I could get around this by having separate "rhythm" and "lead" setups. For an amp like my 100-watt 5150, this is no problem: channel 1 is (mostly) clean, channel 2 is for dirty rhythm, channel 3 is for searing leads.
That's great but what if I'm playing Hendrix or SRV on the clean channel and I just need a little bump? Channel 2 is way too distorted for that style of music. It's almost like I need a channel 1½. The answer lies in ditching my previously-held narrow world-view and embracing the world of "gain stacking".
Flavors of Gain
Before we get too far, we need to understand what gain really is. In simple electronic terms it's the amount a signal is boosted by an amplifier. Under the right circumstances enough gain will cause the signal to "clip" which produces audible artifacts, some of which are pleasing to the ear and others that are not. In the world of the electric guitar this clipping offers a large range of tonal qualities, from the subtle and bluesy to outright face-melting metal (or is it metäl?)
When you're seeking out a particular tone, you need to have some idea of where on the continuum your perfect tone exists. If we had a "gain gauge" for styles and descriptions, it might look like this:
On the far left is where we hear little to no clipping. The traditional jazz sound is good example of what we might call "clean". Now in pure engineering terms a Fender tube amp used for this kind sound is technically "distorting" the signal somewhat. It's part of what makes a Princeton sound the way it does!
As we move further to the right, the gain level increases and so does our clipping level. At the opposite end is what we would call a "distorted" or "high-gain" signal. This is pure heavy-metal territory. Between these two extremes is an endless number of tonal possibilities.
The class Hendrix/SRV sound is somewhere about the a quarter of the way from the left. Classic "hard rock" of the 60's and 70's like Cream and Led Zeppelin are about halfway in the middle. The DLR-era Van Halen records start moving further to the right into the hotter, deeper red territory and anything called "metal" moves further to the right.
This gain can come from a number of places. The obvious source is your amp. If you have a master-volume amp your gain primarily comes from the "gain" or "pre-amp volume" knob. At higher volumes the output section can start adding gain to the signal too.
You can also front-load the gain with a pedal between your guitar and your amp. These types of pedals can range from a subtle blues overdrive, to "crunch", and on to full-on metal distortion. Where things get really interesting is when you stack these sources. Like a submarine sandwich, what you put in there greatly effects the flavor. Some pedal/amp combinations don't work well together and experimentation is the key to finding something you like.
One way I like to "gain-stack" is putting an overdrive pedal in the chain with the gain set anywhere between ¼ to ¾ of the way up. On a moderately clean channel stomping on that overdrives adds just enough grit to almost introduce another channel on my amp between "clean" and "dirty".
Another trick I use often is using an overdrive pedal as a lead boost. On an already moderately-distorted channel adding an overdrive or distortion pedal to the signal path can add a little more sustain to your tone. But, depending on the pedal an amp, can also boost your overall signal a bit as to make your lead lines stand out a little more.
In my normal "rock" setup my amp can produce enough distortion to get me in the ballpark of a good hard-rock crunch. Since the amp can generate quite a bit of gain, I only need an overdrive pedal in this setup. Other times I might be playing a cleaner amp that can't do the same thing. If we have a handful of distorted songs I'll use a distortion pedal here as a simple overdrive may not give me as much growl as I'd like.
Take A Bite
There's no one-size-fits-all recipe that works for everyone. You're just going to have to patiently experiment with what works for your setup and your tastes. If you're testing out pedals at your local guitar store, try to play them through an amp that's close to yours with a guitar that's close to yours. Also remember that how it feels is almost as important as how it sounds.
Beware that stacking too much gain can turn your signal into an unruly mess. Maybe that's what you're looking for, but most of us would prefer not to turn our tone into a howling rainstorm of noise and feedback. If you're amp's gain setting is low, you can get away with more gain on the front-end in your pedal. Conversely with a higher-gain setting on your amp, a little gain on the floor goes a long way. Adding more generally just makes things noisier.
Until next time, keep rocking!