5U3C Tube/Valve for Kondo Audio Note KSL-M77 Clone

First tube photo in a while: A Russian 5U3C rectifier tube, marked 1976 (year of production) and OTK-1, Отдел Технического Контроля, indicating that it passed quality assurance checks before leaving the factory.

The 5U3C is intended for use in a minimalistic new preamplifier that I'm waiting to receive. The design is based on a single 5U3C rectifier tube and two ECC81/6201/CV4024 driver tubes—with British Mullard and Brimar being among the best available.

The Sunbuck preamplifier "clone" from AliExpress -- unethically, some would say -- references the the legendary KSL-M77 from Kondo Audio Note Japan.

The preamplifier turned out to be misassembled — one capacitor had been installed the wrong way around, and it could have exploded if I hadn’t quickly turned it off after noticing the hum and noise.

Fortunately, the power amplifier and speakers weren’t damaged.

Luckily, no harm was done to the power amplifier and speakers.

The 5U3C is electrically equivalent to the American and European 5U4G and VT-244 and the Chinese 5Z3P.

Some people base their choice of amplifiers on their tube collection, like some photographers base their camera decisions on their collection of lenses, I guess.

Pentax K10D & Pentax SMC-A 50mm f/1.2.