For more than 20 years, the MXR Micro Amp has been a staple among the world's top artists because of its ability to boost and sweeten up your guitar or bass tone and drive the front of your amp. The Micro Amp+ builds on that classic pedal with EQ controls and other upgrades that take this powerful boost box to the next level. Its gain knob allows you to dial up just as much gain as the original - up to +26dB - but now with added EQ controls, you can now finely sculpt your boosted signal. For the classic Micro Amp sound, set the bass and treble controls to noon. Additionally, the Micro Amp+ now comes equipped with low-noise op amps - so you don't get any extra noise at super high levels. True hardwire bypass. Powered by 9 volt battery or AC adaptor (ECB003