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28th May 2014, 6:27 pm | #1 |
Octode
Join Date: Jul 2006
Location: Solihull, West Midlands and Beaford, Devon
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PL505 - Short-lived line output valve
Hi everyone.
I was just wondering whatever happened to the PL505 line output valve. How long did it last in manufacture and why was it replaced so quickly? Has anyone ever seen one (I'm sure older TV engineers must have) and does anyone still have one they could post a picture of? Thanks all. Kind regards. From Mike.
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G7TRF |
28th May 2014, 7:12 pm | #2 |
Rest in Peace
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Re: PL505 - Short-lived line output valve
There is a picture of a PL505 here:-
https://www.m-ware.de/en/radioroehre...-pl505/a-1360/ Regards, Mick. |
28th May 2014, 8:09 pm | #3 |
Pentode
Join Date: May 2014
Location: Amsterdam, Netherlands
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Re: PL505 - Short-lived line output valve
I have one or two. Plus one in my Philips K6. If you look up the specs you'll see that the PL505 is only something like 25W whereas the PL509 is 30W and its successor PL519 is rated for a whopping 35W plate dissipation. There were also some design considerations with respect to line output operation but I can't recall what they were. Something to do with g3.
Funny thing that these three tubes look pretty much the same. Tjerk, 9ZZ |
28th May 2014, 8:19 pm | #4 |
Dekatron
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Location: Gateshead, Tyne and Wear, UK.
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Re: PL505 - Short-lived line output valve
The original PL505 lasted only two years in my GEC 2028. 1967 to 69.
DFWB. |
28th May 2014, 8:29 pm | #5 |
Dekatron
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Re: PL505 - Short-lived line output valve
I guess it was all a case of "production logistics" - the burgeoning colour-TV world needed heavier-duty sweep-tubes so it just didn't make sense to keep a lower-power-capacity valve in production when its niche could easily be covered by a much-higher-market-demand/just-as-cheap-to-manufacture-in-bulk valve.
Low demand = expensive-to-run-a-production-line. |
28th May 2014, 9:20 pm | #6 |
Octode
Join Date: Jan 2006
Location: Borough of Gateshead, UK.
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Re: PL505 - Short-lived line output valve
I get the impression the PL505 wasn't quite upto the job seeing so few have survived. I, too, have never seen one.
The same can be said about the PL500. In recent times I was given a Philips branded one so, like the PL505, they did exist! Cheers, Brian |
31st May 2014, 12:26 am | #7 |
Nonode
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Re: PL505 - Short-lived line output valve
I think that G6Tanuki is right. The 1969 January PL505 data sheet refers to that for the PL509 for all parameters other than anode and g2 dissipation. So it would seem that the PL509 was a drop-in replacement for the PL505 that would replicate all of its characteristics but with higher dissipation capability.
Cheers, |
31st May 2014, 8:35 am | #8 |
Octode
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Location: Solihull, West Midlands and Beaford, Devon
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Re: PL505 - Short-lived line output valve
Thanks all for the comments. Most interesting. It'd be nice to get a good one to put in a little-used TV - just for the slightly misguided sake of originality really.
Kind regards. From Mike.
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G7TRF |
31st May 2014, 10:23 am | #9 |
Dekatron
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Re: PL505 - Short-lived line output valve
According to the Radiomuseum first deliveries for the PL505 was 1966.
http://www.radiomuseum.org/tubes/tube_pl505.html However, first deliveries for the PL509 was also in 1966: http://www.radiomuseum.org/tubes/tube_pl509.html No indication which company developed the tube. "Common type Europe" I'd guess it was Philips. Magnoval B9D line output valves were available in the USA before 1966. An example: http://www.radiomuseum.org/tubes/tube_6je6.html DFWB. |
31st May 2014, 12:31 pm | #10 |
Pentode
Join Date: May 2014
Location: Amsterdam, Netherlands
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Re: PL505 - Short-lived line output valve
US tubes had thinner pins and their base wasn't called Magnoval but Novar (JEDEC E9-88). A PL505 would damage an american socket...
The PL505 could very well have been developed by Telefunken. Tjerk, 9ZZ |
31st May 2014, 12:38 pm | #11 |
Dekatron
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Re: PL505 - Short-lived line output valve
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31st May 2014, 1:01 pm | #12 |
Pentode
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Re: PL505 - Short-lived line output valve
On closer inspection, the PL505 has a much tinnier anode construction than the PL509. The latter has a thicker metal and also features extra bars along the sides of the plate to aid in cooling. These are sandwiched between the joints of the two halves. The bar of the PL519 is a bit bigger. Overall sizes are mostly identical so the electrical characteristics will be pretty much the same. The tubes I compared were made by Philips.
Tjerk, 9ZZ |
31st May 2014, 1:41 pm | #13 |
Dekatron
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Re: PL505 - Short-lived line output valve
Radiomuseum.org is not the source you would want to use to research who manufactured a tube originally and when. The data is amongst other things, a bit amalgamated to give a general indication, not to give a detailed history.
My theory is that the PL505 was rushed into production because the PL504 wasn't powerful enough for colour television. The PL509, either by the same or by another manufacturer, was released shortly thereafter while continuous development resulted in the PL519. I own 3 development samples of the PL509, a shorter one, a taller one and a pre-production sample with side-getter designated N31PL from the Heerlen valve factory, I will study them for differences next week and see if I can find a PL519. Last edited by Maarten; 31st May 2014 at 1:46 pm. |
31st May 2014, 1:52 pm | #14 |
Dekatron
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Re: PL505 - Short-lived line output valve
There is further discussion about this series of line output valves on the Forum.
PL500, PL504, PL505 and PL509 have what is called "cavitrap" construction. What is sure we believe these valves have beam forming plates although they are described as pentodes. Reference to this topic on post #268: https://www.vintage-radio.net/forum/...d.php?p=684791 DFWB. |
3rd Jun 2014, 1:30 pm | #15 |
Dekatron
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Re: PL505 - Short-lived line output valve
Hi
As an inquisitive teenager I remember seeing a PL505 in Uncle William's workshop around 1976 - and what's more it was working! It was fitted to an elderly Bush CTV162 19" TV and was doubtless original. I was surprised as I had only ever seen PL509s in sets of that age, probably because the 505s had all died. Glyn |