It’s protected to mention that the majority tasks that function a VFD emphasize the “D” facet greater than anything else. Vacuum fluorescent shows are forged performers, in the end, with their cool blue-green glow that’s simply the precise glance for a lot of unfashionable and not-so-retro builds. However that doesn’t imply there aren’t packages that leverage the “V” facet, equivalent to this nifty audio preamp the usage of VFDs as energetic elements.
The muse in the back of [JGJMatt]’s construct got here from the Korg Nutube line of VFD-based low-voltage dual-triode vacuum tubes. Discovering those explicit elements a little bit at the pricey facet, [JGJMatt] grew to become to the previous standby DM160 VFD indicator tube, which is principally only a triode, to peer how it will fare as an amp. The circuit takes benefit of the low present and voltage necessities of the VFDs — the entire thing runs from a USB spice up converter — through wedging them between a 2N3904 enter level and a 2N2007 MOSFET output. There’s a mixture of SMD and through-hole elements at the custom-etched PCB, with a separate riser card to sing their own praises the VFDs a little bit bit throughout the entrance panel of the 3-d published case.
All in all, we discover this little amp lovely cool, and we adore how it places a twist at the venerable VFD. We’ve noticed identical VFD amps earlier than, however this one’s have compatibility and end in reality will pay off.