The Electro-Harmonix 15Watt Howitzer Guitar Amp and Preamp Pedal is an ultra-compact workhorse perfect as part of a portable guitar rig, or as an emergency backup and gig saver should your main amp break down. It is super flexible, like a musical chameleon, and depending on the gear you use and your style, will fit in the broadest range of genres. The 15Watt Howitzer’s Volume and Gain controls let you go as clean or as crunchy as you want while the Bass, Mid and Treble knobs provide plentiful tone shaping. Its FX Loop gives you the option of putting effects like reverb and delay after the preamp. Of course, you can still run your guitar straight into pedals and right into the 15Watt Howitzer’s input jack. EHX’s Founder, Mike Matthews, said: ‘Dig it. The sandwich-sized 15Watt Howitzer is perfect as part of a compact guitar rig or backup. But the thing I dig the most is the tone that emanates from the Howitzer. It’s super versatile and - depending on what kind of setup you’re running - fits into any style that’s your bag.’ Controls Volume Knob controls the volume or loudness of the amplifier. As you turn the Volume knob clockwise, the 15Watt Howitzer's output gets louder. This knob acts as a master volume control and interacts with the GAIN knob to set the output level. Gain Knob controls the amount of gain and overdrive that is generated by the preamp. As you turn Gain clockwise, the overall signal will get louder and distort. When the knob is turned fully clockwise, the sound will be a warm overdriven tone. Warning: as you turn the Gain knob up, the output level might increase significantly, compensate by turning down Volume. The Bass Knob controls the loudness of low frequencies in the preamp section of the amplifier. As you turn Bass up, the low-end increases. The Mid Knob controls the mid-frequency loudness in the preamp section of the amplifier. As you turn Mid up, the middle-frequency band increases in level. The Treble Knob controls the loudness of high frequencies in the preamp section of the amplifier. As you turn the Treble up, the high-end increases. Connectivity The Input Jack lets you plug the output of your guitar, effects pedal, or any other instrument into the Input jack using a standard 1/4-inch instrument cable. The input impedance presented at the Input jack is 1 M ohm. The Send and Line Out jack outputs the Howitzer's preamp section. Connect Send and Line Out to the beginning of your FX loop or use it as a direct output. The Send and Line Out jack is post preamp but before the Volume knob. If used as a line output with nothing plugged into the Return sound will still be produced from the speaker connected to the Output 8 to 16 ohm jack. The output impedance of the Send and Line Out jack is 47 ohms. The Return jack connects directly to the power amp section of the Howitzer. Plug your FX loop output into the Return jack. The Return jack can also be used as a direct input into the power amp. Plug directly into the Return jack to bypass the Howitzer's preamp section. When using the Return jack as a direct power amp input, the preamp section will not affect the tone. The VOL knob still controls the overall loudness of the amp and the Bright and Norm switch provides a slight high-end boost to the Return signal. The input impedance presented at the Return jack is 1 M ohm. Connect the 15Watt Howitzer's Output jack directly to a speaker cabinet with an impedance of 8 to 16 ohm only.