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Old 14th Oct 2019, 5:15 am   #65
Join Date: Jan 2009
Location: Mt. Maunganui, New Zealand
Posts: 2,495
Default Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition

Some sense of Philips’ general transition from Rimlock to noval types may be gleaned from the Preferred Types tabulations from a couple of Philips valve pocket books.

The first of these is Philips Electronenbuizen Zakboekje of 1953.

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At this time, in the 6.3-volt and 100 mA heater groups, the preferred valve positions were about equally shared between Rimlock (yellow highlighting) and noval (green highlighting) types.

The second is a 1954 Pocket Book.

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By this time novals have displaced Rimlocks as preferred types in all but one case, namely the EL42 car radio output valve. This was replaced by the noval EL85 c.1955.

Some of the Australian Innovals appear never to have been released outside of Australia, as noted below.

6AD8 (EBF81) Australia only
6AN7 (ECH80) Australia only
6BH5 (EF81) Australia only
6BD7 (EBC81) Not released in Europe until c.1954, displacing the EBC41
6M5 (EL80) Australia only
6N8 (EBF80) Released in Europe at about the same time as in Australia
6V8 (EZ80) Not released in Europe until c.1953, displacing the EZ40.

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