Retro VFD Display VU Meter Module for Audio Power Amplifiers

A Vacuum Fluorescent Display VFD may be ancient, but it is still sought for due It is due to its characteristically bright, yet soft, monochromatic display that many find pleasurable to the eye.

This module is an authentic retro VFD audio Volume Unit VU display. Probably built around 1982 - as the IC date code suggests - these are unused original equipment boards that we found lying around in a haunted warehouse. ;-)

This model is a bare VU-Meter module and will work with power amplifiers of sufficiently large output with just the addition of a few external components (i.e. a simple diode AC to DC circuit on each input).

VFD Display: Futaba BG-96Z
VFD Drivers: Hitachi: HA12019
No of levels: 12
Power Supply Voltage: 12VDC 50mA Typical
VFD Heater Supply Voltage: 2.9-3.3V AC or DC, 70mA typical
0 db Input Level: 1.45V Typical

Note: L and R channels are not perfectly balanced. One channel may have an indicator bar ahead of the other. Add trimmer at the inputs to manually balance the channels.

Application Schematic:

A full working application schematic is included in the image gallery. This circuit will work with power amplifiers in 5W to 150W power output range (@ 8 ohms). Adjust the trimmers accordingly for the most desired display range.