Sensibly equivalent¶ to:
The 6064 is a special quality version of the EF91. The special quality valve has a more rugged build than the commercial EF91 and a guaranteed minimum number of hours service life if used under specified conditions, such as bulb temperature etc.
On the side of the envelope is the Trustworthy label as a mark of the special quality build. Mullard used the term Special Quality. All these valves were originally thought of as Reliable valves with a guaranteed long life. The problem was that Reliable implied that the standard valves were not reliable and thus the change to Trustworthy etc.
The thin glass tube envelope is 17 mm in diameter and, excluding the B7G base pins, is 46 mm tall.
Reference: Data-sheet. Type 6064 was first introduced in 1951. See also 1951 adverts.
Absolute Maximum Operating Conditions¶
Updated September 24, 2016.