12-12-2016, 09:17 AM
(This post was last modified: 12-12-2016, 09:19 AM by Mike Watterson.)
The 6418 and similar was developed for military applications, especially proximity fuses in shells and bombs. It may have been for military stock.
I don't think very many valves were specifically developed for hearing aids, it was simply a pubic market for them.
AFAIK no European radios used the USA & European sub-miniature valves, but some USA radios and many Japanese sets did. Often a single B7G for output and 45V HT like an elongated PP3. Usually a C or D torch battery for LT.
I have a few ex-equipment and NOS of the family, including a triode-pentode mixer.
Some US military walkie talkies using valves where still being refurbished and sold abroad by USA even in 1980s!
I don't think very many valves were specifically developed for hearing aids, it was simply a pubic market for them.
AFAIK no European radios used the USA & European sub-miniature valves, but some USA radios and many Japanese sets did. Often a single B7G for output and 45V HT like an elongated PP3. Usually a C or D torch battery for LT.
I have a few ex-equipment and NOS of the family, including a triode-pentode mixer.
Some US military walkie talkies using valves where still being refurbished and sold abroad by USA even in 1980s!
