One thought on “Cossor 12at7/ECC81 D-getter Solid plates”

1. The Cossor 12at7/ECC81 D-getter Solid plates is another fantastic offering from Mullard, this time carrying the Cossor brand. Generally, I avoid reviewing rebranded valves since they are typically identical to their more famous counterparts, but this 1955 gem was simply too good not to share. Produced at the legendary Blackburn factory, this version features a D-getter and solid plates, which are often preferred over the later three-hole plate designs.

   True to the high standards of the mid-to-late 1950s, the sound is exceptional. It offers a massive soundstage combined with a lush warmth and “smooth as silk” transparency. The bass is particularly noteworthy; while it may not have the sheer wall-shaking strength of the Brimar 12AT7 black plates, it is arguably the most refined I have ever heard. The precision is so high that I was hearing drums in spaces I never knew existed—this tube is superbly precise and crystal clear.

   History of the Cossor Brand

   A.C. Cossor Ltd holds a prestigious place in British electronics history, founded in 1859 initially to manufacture scientific glassware. By the early 20th century, they had become a pioneer in the development of cathode ray tubes and early radio valves. In fact, Cossor is credited with producing some of the first British-made radio valves and played a critical role in the development of radar technology during World War II.

   While Cossor was a powerhouse manufacturer in its own right—known for its distinctive “High Vacuum” tubes—by the 1950s, the company was often part of larger conglomerates and shared production with other giants. This led to the era of rebranding, where top-tier Mullard production from Blackburn or Mitcham would be labeled with the Cossor name for distribution. Despite the change in branding, the physical construction and internal date codes reveal that these tubes are built to the exact same industrial-grade specifications that made British valves the envy of the world.

   Final Verdict
   The Cossor 12at7/ECC81 is a masterpiece of refinement. It trades raw power for unparalleled precision and a silky-smooth delivery that makes it one of the best 12AT7 variants from the golden era of Blackburn production. If you find a pair with the solid plates and D-getter, buy them immediately.

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