Tuning a guitar is sometimes quite a challenge. Among the most accurate tuning devices, strobe tuners work differently than regular electronic tuners. They are stroboscopes that flicker a light at the same frequency as the note. The light shines on a wheel that spins at a precise speed. The interaction of the light and regularly-spaced marks on the wheel creates a stroboscopic effect that makes the marks for a particular pitch appear to stand still when the pitch is in tune. These can tune instruments and audio devices more accurately than most non-strobe tuners. However, mechanical strobe units are expensive, and delicate and their moving parts require periodic servicing, so they are used mainly in applications that require higher precision, such as by professional instrument makers and repair experts.
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"
The first Strobotuner was invented by Conn and called Ctroboconn and came on the market in 1936.
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.
For example Jimmy Page's guitar technician Raymond Thomas used the Conn ST-6 Strobotuner to tune Page's guitars behind his backline in the ’70.