AMPLIFIERS & RECEIVERS Douk Audio ST-01 200W Bluetooth Amplifier, 2 Channel Vacuum Tube Power Amp with USB DAC/Coaxial Optical Inputs/VU Meter/Treble Bass Control for Home Theater/Stereo Speakers (Upgrade PRO Version) admin January 31, 2023 • comments off Douk Audio ST-01 200W Bluetooth Amplifier, 2 Channel Vacuum Tube Power Amp with USB DAC/Coaxial Optical… 196 reviews ∼$139.99 2 Channel Vacuum Tube Power Amp with USB DAC/Coaxial Optical Inputs/VU Meter/Treble Bass Control for Home Theater/Stereo Speakers (Upgrade PRO Version) Douk Audio ST-01 200W Bluetooth Amplifier