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ID = 49851
Brand: Philips; Eindhoven (tubes international!); Miniwatt
Developer: Philips; Eindhoven (tubes international!); Miniwatt 
Tube type:  Triode, vacuum 
  Ca. 1925 up to 1945 rare.
Identical to GRDIII = 4603_PHILIPS = B409

Base Europe 4-Pin B4 (Eu A, E, 4A) 1914
Filament Direct

Just Qvigstad

Collection of



Forum contributions about this tube
Threads: 1 | Posts: 3
Hits: 2017     Replies: 2
John Koster

GRD-tubes were used in municipal wire broadcasting networks (G.R.D., Gemeentelijke Radio Distributie) in the 1920s and 1930s in the Netherlands. It als bears the Philips number 4603. These were a series of tubes in the range 4600-4700 for professional use.

Emilio Ciardiello

Dear John,

it is not clear whether GRDIII was a tube or a radiocontrolled distribution system based upon professional 4600-4700 series Philips tubes.

In the text you refer to a series of tubes in the range 4600-4700. But you also write of GRD tubes and all the text is linked to a single GRDIII tube. Do you have more details about?

Many thanks,


John Koster
Dear Emillio,
All Philips GRD (followed by a Roman figure, e.g. II or IV) tubes were used in municipal wire distribution systems in the Netherlands. Most of them were also part of a series of Philips tubes numbered from 4600 to 4700. The GRDIII is also a 4603 tube. The tubes in the 4600 to 4700 range were made for professional use. Some of them have a commercial equivalent. For instance 4610 = E442 and 4693= EF8.
End of forum contributions about this tube

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