: Some designs use tubes like the EF80 as amplifiers for a vintage aesthetic.
At the input side of the schematic, one finds a conventional timekeeping source. This is typically a microcontroller (like an Arduino or PIC) or a dedicated real-time clock (RTC) chip connected to a 32.768 kHz crystal oscillator. This low-voltage digital section generates the raw data: hours, minutes, and seconds. Crt Clock Schematic