Hi all and especially Synchrodyne,
Due to other activities I only saw this discussion when it has almost been finished. Very interesting and much input to digest.
Let me throw in my few pennies of wisdom, purely focussing on the Philips developments, which I've traced back in my
Philips TV and Tuner histories.
As described in that story, the introduction of new valves by Philips post-WW2 went in two waves: in 1947
the Rimlock 40-series was introduced as a major miniaturization step based on the all-glass base. All 1948-49 TV sets were based on the Rimlock valves, with the EF42 as main RF-IF-AM amplifier. Interestingly, Mullard continued the use of the EF50 as main amplifier, switching to the Rimlock series and a design from Eindhoven in 1949.
However, already in the 1946 TV sets 463A and 563A Mullard introduced the EB91, as successor of the EB4, which means that the 90-series was the first in which Philips implemented its all-glass base. This would at the same time be the only 90-series valve used in any Philips TV. The only exception is a DAF96 that was used in 1952 in a French (TF2323) and German set (TD2314) in a protection circuit for the MW6-2 rear projection picture tube. [And to be fair and complete: an EF91 could turn up in UK TVs were the original EB91 sync separator was replaced by an EF91 plus EA50 service solution, see e.g. the 383A in RM.org]. So I fully support your conclusion that Philips never promoted the 90series in its consumer application. However, the EB91 apparently hit a sweet spot, because it was used for 10 years, even alongside the first germanium diodes.
The French Philips/Radiola sets from 1956 were the last to use it, as AGC detector and protection diode. Your interpretation that the EF91 was mainly a local Mullard exercise driven by the UK market is probably correct.
The Noval series was
introduced in 1948. My interpretation is that this base came from the US (RCA I suppose) and was quickly adopted by Philips to give it access to a much larger market. Most Rimlock types were almost overnight copied into Noval types, with all TV sets from 1950 onwards 100% on Noval valves (except the EB91 of course). And with the EF80 as core pentode amplifier covering the RF, IF, AM and FM functions, replacing the EF/UF41 and 42 as well as the EAF/UAF42.
At the time of introduction the EF80 was essentially the best consumer pentode available within Philips, and was thus also used as first RF amplifier in the
first generation tuner modules. At the same time a pentode is obviously not the best solution for an RF pre-amplifier (more noise than a triode) although it survived surprisingly long in that role until replaced by the PCC84 in 1953. The French Philips designers were the first to make the switch to triode RF inputs, using the ECC81, although it is questionable whether that gave an overall better performance, the ECC81 being essentially a low frequency valve.
Throughout the 1950s the EF80 remained the undisputed backbone of all Philips TVs, being used as video and sound IF amplifier. In 1954 it started to be replaced in that last role by the PCF80, while the EF184 replaced it completely as IF amplifier from 1960.
I hope it helps to clarify the story.
Cheers, Pieter