6J1 Vacuum Electron Tube Valve Preamp Amplifier Board Headphone Amp Parts Preamplifier Musical Fidelity Kit AC12V 0.8A

Will this work as a phono preamp?

As there is no wiring schematic, where is the audio input? i assume as this is listed as stereo, the two rca connectors are the audio out.

The kit comes with six diodes, but there are only five labeled on the board. Where does the last one go?

I need to give it 30v for it to not distort, is this normal or are my tubes bad?