Related Clues:

• Guitarist's aid
• Intensify, with up
• Intensify, with "up"
• Concert piece?
• Rock band's accessory
• Crank (up)
• Rock band booster
• Sound investment for a band
• One for the roadie
• Increase, with "up"
• Mike gets juice here?
• Intensify, with 'up'
• Rock band need
• Concert stage item
• It pumps up the volume