100% Built in speaker simulation is an integral part of the CLASSIC Series circuitry. Each model is tuned to match the speaker/cabinet of that amplifier. It is designed for a smooth, even response as would be achieved by a multiply-miked cabinet, without the peaks, valleys, and notches associated with single miking. The shape of the speaker curve not adversely effect or interfere with the frequency response of your own cabinet.There is no need to defeat the speaker simulation circuit when using it with a guitar amplifier. The speaker simulation works in with the EQ controls to custom tailor the overall sound. GUIDE TO CONTROLS LEVEL:Adjusts the output level of the unit.This control has an exceptionally wide range for maximum compatibility with a variety of equipment. LOW, HIGH, MID: On-board post-EQ section gives you full control, like having a studio mixing board at your fingertips. Unlike passive tone controls that only cut, these active controls cut and boost ±12dB. Low is tuned to 125 Hz; High frequency is 3.2 kHz. Mid is custom tuned for each model. DRIVE:Adjusts the overall amount of gain and overdrive, similar to when the output section of a tube amp is being pushed.The first half of the rotation increase the volume as well as the overdrive. VOICE:Voiced differently for each pedal in the series. It sweeps through possibilities associated with each style of amplifier. In addition to modifying the frequency response, Voice also influences the attack and drive characteristic of each particular amplifier style.Therefore, you may need to adjust your gain and tone settings after tweaking control. Input Impedance:1Mohm Output Impedance:1Kohm Power Supply:DC9V 100mA,Center negative(Not included) Colour:Black Material:Metal Size:About 11.5x6.5x5CM Package Contents: 1 * Effect Pedal Only the above package content, other products are no