Conn StroboTuner ST-5 (ST-6) Piano Tuning Organ Vocals instrumental vintage, 195¿, made in USA

Year: 1950 ? 
Category: Miscellaneous (Other, Various) - see notes
Valves / Tubes 6: 12AU7 6AQ5 6AQ5 5879 12AT7 6X4
Wave bands - without
Power type and voltage Alternating Current supply (AC) / 60 cycles AC 105 - 120 Volt
Loudspeaker - - No sound reproduction output.
Power out
Model: Conn Strobotuner ST-6 - Conn, C.G. Instruments Ltd
Material Metal case
Shape Tablemodel, with any shape - general.
The Conn Strobotuner model ST-6 uses tubes and two neon lamps NE2H. It has a microphone with a cable inside the lid including the power cable. The pentode 5879 was introduced in 1950. Schematic and technical picture by courtesy of Terry Smythe (

The first Strobotuner was invented by Conn and called Ctroboconn and came on the market in 1936. On YouTube you find this very well done explanation about the principle of strobe tuners including a more modern Conn Strobotuner - like the Strobotuner ST-12 (or ST-11).

Joseph Plateau of Belgium is generally credited with the invention of the stroboscope in 1831 (1932), when he used a disc with radial slits which he turned while viewing images on a separate rotating wheel. Plateau called his device the "Phenakistoscope". There was a simultaneous and independent invention of the device by the Austrian Simon von Stampfer, which he named the "Stroboscope"