The Vintage Ultra is the result of the finest engineering process Darkglass has ever accomplished. 40 years ago it was necessary to carry a massive amp to have a rich, tight and articulate sound for bass players. Today, all you need is a super portable preamp which enables on one side a massive clean sound, and from the other side, a tasty saturated sound. This is a true elixir for low end lovers. Whereas the Level Knob controls the output of the overdrive section the Master volume adjusts the overall volume of the unit. Ideal for fine tuning the output on clean mode. It also serves as a DI level control. Blend mixes the clean input signal with the overdriven signal. The clean signal remains at unity gain while the volume of the overdriven signal is set by the Level knob, allowing for fine control of the blend ratio. Attack switch sets the amount of treble content to saturate: The "Boost" setting emphasizes the treble content extra clarity and presence. The "Flat" position leaves this register untouched while the "Cut" position will reduce the amount of high frequencies being saturated. Grunt switch sets the amount of low frequency content to saturate by selecting between three different bass boost levels before the clipping stage. The Vintage Ultra has a current draw of 30mA. Only use a regulated 9V DC adapter with a center-negative plug. Due to ecological reasons it does not accept batteries.