Volume unit (VU) meters are cool — it’s an undeniable fact. For some reason, humans just dig lights that flash along with sounds. You can build a VU meter using LEDs, or bulbs if you’re trapped in 1972. Or, you could use special vacuum tubes. [mircemk] did just that in their latest VU meter project.

The 6E2 vacuum tube is the part for the job in this case. You might think a specialist tube like this is expensive, but they can be had for just a few dollars from online retailers. They were often used as tuning indicators, but here, they’re used as a responsive VU meter instead. However, instead of a single bar going up and down, you get a pair of bars that raise to meet in the middle.

[mircemk] explains all the circuitry required to drive the tubes, and how to hook them up to create a two-channel stereo VU meter. The final circuit largely relies on a transistor, a diode, some passive components, and a DC-DC boost supply to generate 250 V for the tubes.

The final result looks pretty neat, particularly as it’s built into an old-school blue project box. We’ve seen similar projects from [mircemk] before, too.