Tube amp type overdrive equipped with JRC4558D circuits. One of the sound characteristics of the OD820 lies in its power section, even though it runs on a 9V power supply, an internal converter boosts it to 18V, allowing a better and more complete reproduction of frequency range. The other secret to the OD820 is its Blend setting, allowing to mix the effect with the unaffected dry signal. 9V power supply included.