Here is what you do. Cathode follower 6AS7 biased at around -30V Operate 75V PSu with a choke load or 150V with a huge 15W resistor load. Bandwidth will be DC to light. Have a good (not botique) film cap for output. Don't even think about a 'lytic. In https://jaschag714bqg5.wikisona.com/user