Input Jacks. This, believe it or not, is where you plug your guitar into the amp! Gain Control. This adjusts the overall preamp gain of the amplifier. This control can produce a wide variety of killer tones - from clean to crunchy to crazy and all points in-between! What you get all depends on how you set this control and also how you have the Clean/Overdrive Switch (3) set. In both Switch modes - Clean & Overdrive - turning the Gain control down (i.e. counter clockwise) will clean up your sound while cranking it up (i.e. turning it clockwise) will dirty things up. The possibilities are endless. Clean/Overdrive Switch. As its name suggests, this switch puts the preamp of the Pathfinder 10 in one of two distinctly different modes -Clean (switch "out") or Overdrive (switch "in"). And, as you'd expect, the Overdrive mode has bags more gain than the Clean mode. So, if you want more gain just press this button in and let rip! Treble Control. This adjusts the treble (high) frequencies in your tone. It can take your sound from soft and round, to bright and cutting, and any point in-between. Bass Control. This adjusts the bass (low) frequencies in your tone. It can take your sound from warm and light, to dark and heavy and any point in-between. Volume Control. This determines the overall volume of the amplifier. Setting this control high while keeping the Gain low works well for clean sounds (HINT: make sure the Clean/Overdrive Switch is "out" if you wanna go clean!), while setting the Master Volume lower, engaging the Overdrive mode and turning up the Gain will give you a fat, distorted sound at a lower, "bedroom friendly" volume. Headphone/Line Out Jack. This dual output carries a specially filtered signal for use with either headphones or for direct connection to a soundboard or recording console. The LINE OUT gives you a good sounding signal for recording or live work without having to mic up the amp. Inserting a jack-plug into this jack will mute the internal speaker. Power ON/OFF Switch & LED. On/Off switch for mains (AC) power to amplifier. Plus power indicator LED.