What equipment uses 6267 Tubes

I have several NOS 6267 tubes. I have no idea what they are used in. Heck getting old. Any help would be appreciated.
They are used in Neumann Microphones and many guitar amplifiers, also known as EF86.
It is equivalent to the European EF86 type, which was used in some vintage Quad pieces such as the Quad II mono-block power amplifier.

In case it is helpful in determining other equipment in which it may have been used, my Sams tube substitution handbook lists the following as substitutes for the 6267: 8D8, 6F22, EF86, EF87, EF806S, M8195, Z729. The 6267 is listed as a substitute for the 6F22, EF86, EF87, and Z729, but not for the others.

-- Al
Lots of German table radios from the 50's/60's, Telefunken, Grundig, AJA, Nordemende, Blaupunkt and more.