6П3С/6N3С/63PS

6П3С-, 6N3С-, and 63PS are three terms for the same type of vacuum tube (valve in British English). The reason for the different names is that it's a Russian-made tube, where some are labeled with Cyrillic letters, by some producers and writers converting the Cyrillic ø П ‘ to a ‘P’ (which is the closest letter from Russian to English) or an ‘N’, which looks the most similar to the Russian ’П’ letter. Many tubes in the same family - often under both Russian and American/English family names If you want to add further confusion, 6П3С-, 6N3С-, and 63PS tubes are related (sharing characteristics in different domains) to the following tubes: 3108_OSW; 6L6G; 6L6GA; 6L6_DDR; 6Л6С; 6П3; 6П3С-Е; OSW3108 - which to varying degrees are equivalent to the corresponding American tube series in the 6L6 and 5881 families. The 6П3С-, 6N3С-, 63PS- was popularized more broadly 10-20 years ago at a time when prices of 5881 and 6L6 tubes from American manufacturers like Tung-Sol, RCA, Sylvania, and General Electric skyrocketed due to simple supply and demand. -- Part of my 'Objects for an Ideal Home' series, https://bergholt.net/objects