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-mixed cabinet, without the peaks, valleys, and notches associated with single mixing. The shape of the speaker curve will 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 tandem with the EQ controls to custom tailor the overall sound. Features: 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 will increase the volume as well as the overdrive. VOICE: Voiced differently for each pedal in the series. It sweeps through various tonal 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 the Voice control. Note: Use only regulated 9V D/C adapter center negative polarity. Specifications: Material: Metal Color: Purple Input Impedance: 1M Output Impedance: 1K Power Supply: D/C9V 100mA,Center negative Item Size: 115*65*36mm / 4.52 * 2.55 * 1.41in Item Weight: 262g / 9.24oz Package Weight: 311g / 10.97oz Package Size: 13.5 * 6.4 * 7.8cm / 5.31 * 2.51 * 3.07in Packing List: 1 * Guitar effect Pedal