Seymour Duncan 11993-17 STC-2ASB 2-Band Preamp for Active PickupsHigh headroom, low noise, 2 Band active onboard EQ preamp voiced specifically for fretless basses with active pickups. Seymour Duncan Tone Circuits will add a tremendous amount of on board tonal versatility to any dual pickup bass. Our design enables players to boost or cut specifically focused frequencies in order to achieve signature tones and to dial in a great sound no matter what the situation. We even added the two small trim pots on the circuit