If you find a tube with a getter in the form of a flying saucer, you can ignore any branding on the tube. It’s practically guaranteed that you have a Soviet/Russian made tube. Some of them are great, like EV/DR versions of tubes, but in the majority of cases, they don’t sound good.

The following Special Quality types are recommended as plug-in replacements for the corresponding commercial types. Substitution in the reverse direction is not recommended.

Brimar (BRItish Made American Range) was a part of Standard Telephones and Cables Ltd (STC) and was founded in London as International Western Electric in 1883. From 1925 to mid 1980s the company was owned by ITT of the USA.

There is very little information available on how to read Brimar tube codes, but in general, they are one of the easiest to decipher.

The code consists of multiple sections and usually look like:
4G9/980 (4th week of production in July of 1959, tube type 6060)

BTW, if Brimar labeled tube doesn’t have the date code or it has Foreign stamped on the tube, it’s not produced by Brimar, but by some other manufacturer. Many Brimar labeled tubes are actually Soviet made.

The Brimar “T” Yellow Label

In addition to the etched date codes, you will frequently encounter Brimar tubes—particularly from the late 1950s and 1960s—featuring a prominent yellow “T” logo on the glass. This was not a decorative choice; it signified a specific grade of vacuum tube designed for high-reliability applications. The “T” stands for Trustworthy. These were Brimar’s “Special Quality” (SQ) valves, engineered to be more robust than their standard commercial counterparts. They were the British equivalent of the American “Ruggedized” or “Premium” lines (like the GE Five-Star or RCA Command series).

Deciphering different tube codes is hard even when they are in your own language. Deciphering Soviet tubes is even harder since the majority of information about them is in Russian.

Here is some information about common suffixes: