Audio A3 PRO 6K4 Tube Preamplifier — HiFi Tube Preamp Buffer Amp, High Sound

Important usage notes for the Audio A3 PRO 6K4: This unit is a preamplifier only, not a power amplifier. It must be paired with a downstream power (post) amplifier or with active speakers — do not hook passive speakers, standalone speakers or earphones directly to this unit as if it were a power amp. Failure to use the proper amplification stage can cause damage; if supply voltage is unstable the car may be burnt. Poorly filtered audio lines or power supplies increase the chance of low-frequency hum or background noise. For best results, use quality audio cables and a stable, well-filtered power source. Verify your source device before blaming the preamp: the preamplifier will faithfully amplify any noise present in the input signal, so test with a clean sound source. Finally, inspect the vacuum tube seating: ensure each tube is fully inserted into its base. Make sure tubes are installed correctly (and handled with power off) to avoid problems in the event of a power fault.