Quote:
Originally Posted by Maarten
Quote:
Originally Posted by kalee20
One thing I have noticed between B8A rimlock, and B9A noval (and B7G), the pins of B8A valves are hard and stiff, whereas the others aren't.
I can see the need for pins that bend, if the valve is knocked sideways in the valveholder then the pins bend rather than the glass breaks. And B8A valves are supported by the skirt anyway so the force is not taken by the pins. But given that bendy pins would not detract from the valve in B8A, and given that the alloy had already been developed for B7G, what did B8A have rigid pins? Or was it just cheaper?
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The design of the glass base and pins was likely based on the older B8G base, so developed before the B7G. |
The issue of pin stiffness and shortness of the internal links was addressed in the second link in post #41,
https://www.radiomuseum.org/dsp_mult...s_innovals.pdf. See pages 5 and 6.
The stiff pins, some extended well upwards into the valve, were a specific feature of the Rimlocks, and one that Philips saw as an improvement on the B7G and American B9A structures. Thus it was carried over to the Innoval series, which was thus said to combine the best features of the Rimlocks and the novals. But Philips does appear to have reverted to the conventional B9A noval structure within a few years.
Notwithstanding that Philips developed the Rimlock form for its main domestic receiving valve series, it also started manufacturing B7G miniatures at about the same time as it started Rimlock production. The B7G range included not only valves for battery portable receivers, where minimal valve size was obviously important, but also industrial valves such as the EF91, EB91, ECC91 and so on. Presumably Philips simply followed the standard B7G pattern when it came to the pins and lower internal structure, and did not apply its Rimlock ideas to these valves.
As another facet to the Philips noval/Innoval story, it would be useful to find Philips’ initial release on its TV World Series valves. All but two of the initial range were on the noval base, so it would be interesting to see how this feature was presented as compared with its Australian Innoval material.
Cheers,