Quote:
Originally Posted by jr_tech
Interesting, Thanks for posting! I have never seen one, and my tube manuals (early-mid 60s) don't list any 25 inch P-4 (B/W) jugs. However, in a Sams pocket sized "Tube Substitution Handbook" 1972 printing, I found listings of 25DP4, 25HP4, 25JP4, 25KJP4, 25LP4, and 25TP4. With color TV rapidly gaining popularity in this time frame, I suspect that sales for these large screen B/W sets were rather poor. 
jr |
Radiomuseum.org shows the 25LP4 and 25TP4 being used in several sets for the Australian market in the mid-to-late sixties (note that the market for big monochrome sets had not been displaced by color sets as Austrailan TV transmissions were still monochrome).
The 25DP4 and 25DP4 show up on frank.pocnet, with tube manual pages from Sylvania, from 1965. It's a bonded front tube, with the front about the same shape as the 25XP22, but a slightly larger picture than the 25XP22. I would be really curious to know what, if any, TV sets used this tube.
I must admit I have a weakness for big B&W sets, it dates back to my hobby of fixing discarded sets when I was a teenager. When I saw how much more complicated color TV sets were, I wondered why anyone would have wanted a color TV!