From the MAKE: Flickr pool
5Volt turned an old VCR’s vacuum fluorescent display into a headphone amp –
VFDs are common on VCRs. I have a few of them I took from some broken VCRs. Last night I was working on how I could use them as vacuum triodes. I donâ€™t have much experience with real vacuum tubes so I had to invent some, possibly wrong, arrangements, but I finally got something.
Schematic and further details available – A Vacuum Fluorescent Display as a headphone amplifier