There are so many great tubes with what’s called Foil Getter. But what is it? How does it look?
The image above shows one version of a foil getter from European tubes. These very desirable tubes since they have been produced in the mid to late 1950s. Amperex and Philips are known for their Foil getter tubes that are considered to be one of the very best – Amperex 12ax7, 12au7 Foil, 12at7 Foil, etc. These tubes have also darker getter flash, looks almost burned.
Mullard on the other hand hasn’t ever produced foil getter tubes, their earlier versions have D-getter with 2 connecting rods. Telefunken always used O-getter based on my experience.
Additionally, this kind of getter can also be found in RCA 5963 tubes from the mid-1950s.
This is another foil getter from RCA – these have been produced from the late 1940s (the earliest of 12au7) to the early 1950s.
This is an example of RFT ECC85 with their version of a foil getter. Tungsram also used similar-looking getter in their early tubes.
So, are these tubes better than other getters? In short, yes. The tubes have been produced in the early days of miniature audio tube production and usually have great transparency and warmth – a hard combination to get in a tube. A long answer, it depends. For example, RCA 5963 is a good, but not great tube. I’m sure there are more types, but these cover the main miniature types.