- The most versatile Aguilar bass preamp - +/- 18 db for Bass (40 Hz) - +/- 16 dB for thomann Mid (400 or 800 Hz) - +/- 16 dB for Treble (6.5 KHz). - Can be operated with one or two 9V batteries - Preamp - 3 Potentiometers for bass, mid and treble - Mini-switches for the selection of the central frequency EUR 218.00 - See more - Buy online