PL505 - Short-lived line output valve - UK Vintage Radio Repair and Restoration Discussion Forum

Mikey405 · 28th May 2014, 6:27 pm

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.

mickjjo · 28th May 2014, 7:12 pm

There is a picture of a PL505 here:-

https://www.m-ware.de/en/radioroehre...-pl505/a-1360/

Regards, Mick.

PE9ZZ_JO22KI · 28th May 2014, 8:09 pm

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

FERNSEH · 28th May 2014, 8:19 pm

The original PL505 lasted only two years in my GEC 2028. 1967 to 69.

DFWB.

G6Tanuki · 28th May 2014, 8:29 pm

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.

Focus Diode · 28th May 2014, 9:20 pm

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

Synchrodyne · 31st May 2014, 12:26 am

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,

Mikey405 · 31st May 2014, 8:35 am

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.

FERNSEH · 31st May 2014, 10:23 am

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.

PE9ZZ_JO22KI · 31st May 2014, 12:31 pm

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

FERNSEH · 31st May 2014, 12:38 pm

Quote:

Originally Posted by PE9ZZ_JO22KI

The PL505 could very well have been developed by Telefunken.

That's right, there is a tendency to believe that every European valve was developed by Philips.

DFWB.

PE9ZZ_JO22KI · 31st May 2014, 1:01 pm

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

Maarten · 31st May 2014, 1:41 pm

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.

FERNSEH · 31st May 2014, 1:52 pm

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.

Welsh Anorak · 3rd Jun 2014, 1:30 pm

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

28th May 2014, 6:27 pm	#1
Mikey405 Octode Join Date: Jul 2006 Location: Solihull, West Midlands and Beaford, Devon Posts: 1,626	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. __________________ G7TRF

28th May 2014, 8:09 pm	#3
PE9ZZ_JO22KI Pentode Join Date: May 2014 Location: Amsterdam, Netherlands Posts: 202	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
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	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
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	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
Focus Diode Octode Join Date: Jan 2006 Location: Borough of Gateshead, UK. Posts: 1,420	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

28th May 2014, 7:12 pm	#2
mickjjo Rest in Peace Join Date: Jul 2004 Location: Dartford, Kent, UK. Posts: 1,661	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.

31st May 2014, 12:26 am	#7
Synchrodyne Nonode Join Date: Jan 2009 Location: Papamoa Beach, Bay of Plenty, New Zealand Posts: 2,944	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
Mikey405 Octode Join Date: Jul 2006 Location: Solihull, West Midlands and Beaford, Devon Posts: 1,626	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. __________________ G7TRF

31st May 2014, 10:23 am	#9
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	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
PE9ZZ_JO22KI Pentode Join Date: May 2014 Location: Amsterdam, Netherlands Posts: 202	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, 1:01 pm	#12
PE9ZZ_JO22KI Pentode Join Date: May 2014 Location: Amsterdam, Netherlands Posts: 202	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
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,199	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
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	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
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,921	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