VII. Line 6 Drive

This may actually be the best distortion effect in the Pod. Its Mids parameter varies the type of distortion you get, so as you go from 0%-100% you go far from farty to almost fake-sounding tight djentiness. I don't go too far off 50%, but there's so much ability to dial this in, I don't need to. Once you find your Mids spot, then use Bass and Treble to dial it completely in.

I sometimes like to run a Mid-Focus EQ before or after this distortion to trim some of the ultra high-end if I'm trying to get a super bright distortion, because it can make it too bright in the very high frequencies, which tend to make amps create a grittier tone with a more broken up attack. With more conservative settings, it's not (or less) necessary, but is something to keep in mind.

I mostly use it as a filter (0% Drive), but it seems like I get the best tone when I attenuate my signal before this effect with a Volume effect, to make sure it's not distorting or even compressing at all. It does work well as a standalone (high Drive) distortion, and I also occasionally use it to add a slight bit of distortion and run it into amp distortion to get a nastier tone with a little buzz.

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VIII. Others

I find the others sound fake or just crazy. They'd be good for a kind of out-of-control intro tone, but I don't really mess with that very much.

The Heavy Distortion is supposed to be modeled after a Boss Metal Zone; but without the adjustable mid-frequency, it is nowhere near as versatile. I find I prefer to use the Line 6 Drive (which does have the adjustable mids contour) or Line 6 Distortion (which is more dialed in where you'd kind of want it) where I would use this.

The Jumbo Fuzz is supposed to give you a Zepplin tone, but I haven't tried it yet. The Fuzz Pi is all over the place, which I haven't found a use for - maybe Nirvana? The Jet Fuzz is a phaser + distortion - I think I'd prefer to keep those separate. Same with the Octave Fuzz - I'd rather use separate effects and have more control over each.

The Buzzsaw and Color Drive seem to just add some dirt into the tone - definitely not my thing.

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F. Power Amp d.E.P.'s

The best approach to these is to treat them like you would on a real amp. You'd likely spend most of your time finding the sweet spot for the master volume. Next you'd likely tweak the bias. Sag, hum, and bias excursion would be more complicated modifications to the amp that probably won't help the tone, other than the slight variation in such parameters you'd get from using different tubes.

Master

This controls the amount of power amp compression/distortion, similar to the master volume knob on a real amplifier. This setting affects how much the other DEP settings affect the tone - they are colors of power amp compression/distortion. Setting this to lower settings (even all the way to 0%) approximates the tone of the pre-amp only models. This is helpful to dial in a sweet spot between the default "pre" and "full" amp models. It is also useful to dial out unwanted power amp distortion on cleaner models.

For the high-gain models, the default 50% sounds about where I like it. I may tweak a little this way or that way to make the tone a little edgier or smoother, but I generally don't go far. The Treadplate becomes rather harsh at higher settings, while the Fireball and Uber tend to compress and get a little more life in the midrange, at the expense of high-end richness and smoothness. I like to turn up the power section to around 65% on the J-800 usually, which offers a more aggressive distortion than its preamp.

Sag

Controls the amount of power amp sag, which is a dip in voltage over a sustained load. I find it mainly causes a slower attack and a chunkier bottom end. See this wikipedia entry. Lower settings offer more of a dynamic attack and tighter feel, but can change the tone.

In general I leave this alone until I've made almost all my other tweaks. I'll use it to add more/less attack to the tone. I usually stay within 40-60%. Lower settings can make the tone a bit edgier bit thinner. If I want to thicken the tone up, I usually add Decay in the Cab DEP's to do so. But sometimes, I like to turn up both Sag and Decay to get it extra thick.

Some distortion effects introduce their own kind of sag to the tone, so you actually want to reduce the Sag DEP to compensate. Too much sag or thickness to a tone can make it sound artificial - like a solid state pedal that claims to give you teh brootz tonez. But not enough Sag and your palm mutes will sound more like an overdriven clean-channel crunch tone than a thick djent tone.

Hum

This controls the AC ripple plate voltage, which affects how the power tubes behave. For some amp models, this control has little effect; for others, it can be dramatic. It's hard to describe, and it varies from amp to amp. Also, the changes in tone are not completely linear. IE - if you find it to sound warm at 50% and cold at 25%, it's not necessarily going to sound really cold at 0% or really hot at 100%. Be warned: this control can cause weird things to happen to your tone when you move it off 50%. For instance, I liked the tone when I turned it up from 50 to 70% on the Uber model but noticed it introduced a faint, kind of digital-sounding ghost signal doubling my guitar parts. I almost always leave this control at 50%.

The big exception is the Uber model. I find a touch more Hum (55-60%) changes the distortion to thicken it up a little and make the overall tone a bit darker, which I really like. I also find setting it around 75% gives me a more evil tone, which I use to approximate a 5150. I have not had such luck manipulating this control on other amp models.

If you do choose to boost this, pay attention to your Master DEP setting. You will have to balance the two or you'll end up with a tone that hums and swirls and sounds like an out-of-tune radio. You can tell you've got too far when this control noticeably increases the amount of humming when you're not playing (provided you don't have a noise gate that is muting it).

Bias

Determines the bias of the power tubes. Lower settings resemble class AB operation where you have more headroom and where you do get clipping, it is more natural sounding. Higher settings resemble class A operation, which is often said to sound warmer (more mids/presence) but can get grittier-sounding clipping.

I recommend playing with this control from 0 to 100% for your patches. It can cause subtle frequency response changes to the tone that you can't get using EQ. It seems to improve the signal-to-noise ratio for certain frequencies. It can also change your distortion tone. While I generally end up around 50%, I'm usually slightly one way or the other. In some cases, I'll have this at 100% while others at 25%.

For some of the more vintage amp models that exhibit crossover distortion, turning this up can reduce or eliminate the crossover distortion; however, it will have a significant impact on tone. I prefer to reduce the Master DEP and boost Bias X.

Bias X

Controls bias excursion or how far the bias can deviate from its setting under different loads. I find this has the most effect on cleaner tones where the attack of the signal can be a spike exponentially larger than the sustained note - I've found higher settings clean up attack without sacrificing tone, acting like a compressor/limiter. Also useful to "lock-in" a bias setting by turning it down when you're getting power amp distortion. Or you can get some "bloom" to notes by turning it up.

Bias excursion seems to operate in phases. When a load is first applied (ie, when playing a note), the voltage overloads the tube, and the tube biases away from its normal setting. It then hits a point where it begins to recover and return to its natural bias. I assume this is why I feel like boosting this parameter can add "bloom" to a sustained note.

I most often leave this alone, or turn it up to get the vowel-y bloom effect I just mentioned. Just be careful. While at first it can generate some compression and a slight change in the distortion character, which as this transitions over time gets the "bloom" effect, going too far can make the entire tone change, in a way I feel is bad. Certain frequencies are not reproduced well, and the tone seems more noisy and dull. I find I like 65-70% and that's with a power section not being pushed very hard. The most I'll ever do is 80%, and that's when I've got the Master DEP set low, like 20%. Beyond that is the tone graveyard.

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