audio pre amplifier 1.100% handmade 2. High quality, best sound 3.Can offer customized amp 2 channals tube audio pre amplifier Vacuum tube: 1 x 5Z4P , 4 x 6N8P tubes.Advantages:*100% Handmade circuit board for vacuum amplifier,with excellent sound and low distortion.*Provide OEM/ODM service.Can brand your logo onto our products, or make new models according to your design and specifications.