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Tube Philips 505 Cine Sonor (.33.)

Jacob Roschy Martin Renz Ernst Erb Bernhard Nagel Eilert Menke 
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Forum » Valves / tubes - Semiconductors » VALVES/TUBES / SEMICONDUCTORS in RADIOMUSEUM » Tube Philips 505 Cine Sonor (.33.)
Georges Van Campenhout
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27.Mar.10 18:48

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Dear Radio friends,


I recently received a Philips Tube, model 505.

On top of this tube is written (see pictures)







Inside, one can clearly distinguish two diode systems!

I wonder if this is the same tube??




This article was edited 27.Mar.10 18:49 by Georges Van Campenhout .

Jacob Roschy
Jacob Roschy
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27.Mar.10 21:24

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Hello Georges,


since this tube has merely 3 pins, it can't be anything else then a half-wave rectifier, although two diode systems are visible. It's very likely that you can find a parallel connection inside the tube. I have very little doubt about the correct designation 505.

This method was even used in some other cases: have a look at the second picture of the rectifier type 1803 (under “more”) - and you can see a 1803 which is made in the same way. The connection between the two anodes is clearly visible.

Best Regards, Jacob



Georges Van Campenhout
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28.Mar.10 11:04

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Thank you, Jacob.

Indeed, looking carefully into the glass base shows that the two heaters are connected in series.

But what about the other marking: CINE SONOR?

Was this rectifier used only for cinema applications? Or is there another explanation?


Best regards





Georg Richter
Georg Richter
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28.Mar.10 15:16

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Philips Eindhoven had a "Cine Sonor" department for cinema equipment production (like Siemens had a separate company "Klangfilm").

It may be that Philips tubes which are labeled "Cine Sonor" was sold for a higher price for "dedicated application", similar to the "Klangfilm" tubes which was (often) standard tubes with a different numbering system to prevent cinema operators to use cheaper tubes for replacement. As far as I know the cinema operators had to sign a contract with the cinema equipment supplier.

I do not know if those "cinema" tubes has had a higher reliability or was selected for reaching the upper limits of the specifications.

If somebody can quote a contract between cinema equipment manufacturers and cinema operators, or can provide data sheets or an advertisement folder of Philips "Cine Sonor" equipment we will know more.

Best Regards