The type Z66 was M-OV's late-1930s in-house attempt to make a small, modern high-slope pentode for wide-bandwidth IF systems in TV and radar, where bandwidths of several MHz were required.
This is an earlier example than our other Z66's as it has the metal skirt and not the composition base.
To ensure that the valve would be cheap and easy to make, a 'pinch' construction was used that could be assembled on existing production line machinery. Sadly the Z66 was very much a 'second best when it came to performance, particularly in terms of gain-bandwidth product and high-frequency noise figure.
The high bandwidth receiving valve that won the War was the pinch-less EF50 not the Z66, even though they had comparable data-book characteristics. The extra lead length added too much inductance.
The remains of the Osram brand label. The test results are on the sticker.
The copper control grid supports and rectangular cathode tube.
Looking up from the base the heater leads can be seen entering the cathode. The separation suggests that more than a single loop is used - probably four strands.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 80 mm tall.
References: 1043 & Data. Type Z66 was first introduced in 1948. See also1948 adverts.
