The Dirty Little Secret (DLS) is an overdrive pedal designed to bring you the sound and response of a classic Marshall ampli­er. Its like the other pedals in Foundation Overdrive range of pedals, is designed to be a foundation pedal - it is your always on pedal that forms the core of your guitar sound which you can enhance and embellish by adding boosters, fuzzes, ­lters, and other overdrives in front of it - just like you would in front of a real amp. And the reason you can leave it always-on is that you can get a great clean sound just by rolling your guitar's volume knob back.Super LeadThe Super Lead mode gives you the great rock sound of a Marshall Super Lead amp with awesome harmonics, touch sensitivity, cab thumb, and kerrang. Higher gain than the Super Bass mode, Super Lead mode is perfect for use with humbucker-equipped guitars. Its gain range goes from classic plexi all the way to modi­ed JCM800 levels. And, just like a great plexi, you can go from clean to scream with just a twist of your guitar's volume knob. Like a Super Lead, its voice is all about thump and upper-midrange kerrang. Super BassThe Super Bass mode gives you the tone and gain structure of a Marshall Super Bass (which is very similar to a JTM45, JTM50/100, or very early plexi). This mode was voiced to really hone in on that elusive in-between not quite clean, not quite dirty response that old tube amps were so good at getting. And it was speci­cally voiced to make fuzz pedals sound great (especially two-transistor-based fuzzes like the fuzz face). Plug a Strat into a Fuzz Face into the new DLS in SB mode and you'll see what we mean! Its voice is deeper bass, and an emphasis on the lower midrange band (in contrast to the Super Lead mode's upper midrange emphasis) and sounds especially great with Fender-style guitars.Treble KnobThe treble knob is important. Circuit-wise, it is actually a sort of 'mixer' control, mixing between the treble side and the middle/bass side. So if you want a less bassy sound, not only would you turn the Bass control down but you might also want to turn the Treble control up to 'mix' less of the middle/bass frequencies into the sound.Middle KnobThe Middle knob can also be thought of as a sort of 'gain' knob since most of the guitar's energy is in the middle frequencies. So if you want the grainiest sound possible, run the Middle knob high. But if you want a less grainy sound run it lower. This means you might also want to run the Treble and Bass knobs even lower to balance things out.Bass KnobThe Bass knob lets a lot of low-end through in either mode. In SB mode, the lows boosted are deeper. And in SL mode the lows affected are up slightly higher, right in the 'thump' zone. So in SL mode, you get prominent upper mids from the Treble and Middle controls and thump frequencies from the Bass knob - perfect for a rock sound that is full yet cuts through the band mix! No wonder Super Leads were used by, um, almost everybody!Pre-AmpThis controls the gain or amount of overdrive. The new DLS was tuned to allow a bit more gain than most plexi Marshalls actually got. Super Bass mode was tuned to have less gain than the Super Lead mode to get more of that early Marshall response.