Quote:
Originally Posted by Nuvistor
It’s fascinating to me to have first hand information about the radios and TV used in the USA.
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From down here in the Antipodes, I have had the opportunity to look objectively at very early TV sets from both the USA & the UK. Since television here started in the late 1950's here, the sets we have here that are older than that were imported.
As a general rule many early UK TV sets were AC/DC or transformer-less designs. While nearly every American set had a power transformer. Plus, in American sets there is a paucity of aluminium. They used it for IF transformer shields but that is about it. In UK sets often the entire chassis was aluminium like the Bush TV22.
VDR's (voltage dependent resistors like NTC's, and Metrosils) were common in UK sets and hardly ever used in American sets.
American sets pioneered the use of Turret tuners earlier than the UK sets. And even though the efficiency diode concept was worked out by Blumlein, pre war, the Americans (RCA) were first to commercialize it.
What we now know as the "standard monochrome television design, complete with efficiency diode & inter-carrier FM sound" appeared from RCA in 1946 as the RCA 621TS model.
All American post war TV sets, regardless of brand or model, followed this 621TS format, while the UK sets lagged behind before they caught up in the mid 1950's. The 621TS was designed during the war, but the war delayed its release. Here is a restoration of a 621TS:
http://worldphaco.com/uploads/621TSARTICLE.pdf
It is worth mentioning that the power transformers in many American sets are not well suited to 50Hz operation. The primary currents are high with magnetic saturation on this frequency and they have very large radiated magnetic fields and very high off load primary currents. They simply run too hot on 50Hz.
In two American TV sets I have, the 621TS and a Meissner 1939 pre-war set, both the power transformers required replacing for this reason (we are 50Hz here in Australia). Fortunately there are modern power transformers made by Hammond which solve the problem.