Aye, as I have noticed the lanterns look more whiter than usual, suggesting that their no longer MBF but CFL.

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From streetlighting to radio, dance through the night whilst the streetlights are glowing outside.

Nope nothing to do with that, many "conventional" lanterns columns of that era were remote geared as well.

It is more to do with the shape of the ballast. A fluorescent ballast can be made long and thin so could be fitted inside the lantern - most fluorescent lanterns of that time were internally geared. However for MBF and SOX you need a "square" ballast which won't fit inside the lantern. For SOX leak transformers to be efficient they need to be squareish for the coupling between the coils to be most efficient. Modern ignitor ballasts only have 1 coil which allows those to be long and thin - look inside a Mi26.

MBF lamps will run on conventional linear ballasts indeed that is how the very early fluorescent tubes were operated - they used MA gear. However at the time the Gamma 9 was made a 80W MBF ballast was a lot bigger than the ballast required for a 40W fluorescent tube. I suspect Thorn used 2 or 4, 40W ballasts, one per tube. They could have used 2 of those ballasts in series for a 80W MBF but it is less efficient in cost and power to do that.

Note Thorn's typo:



Now that would be a big tube!

I spotted that typo too! and because I was tired, I started trying to count up 4 X 40w and couldn't make it add up to 440w!!!

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That's an 8896. The 8691 is the geared version...

I meant to say its a GEC Z8591,    the Z8896 has a different canopy, spigot entry and bowl clip. This is a Z8896.

Bah! I thought was being clever then....

I can see it appears much more rounded than an 8896... I wonder if the bowl from that would fit an 8896/8691 though.

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The Z8591 has the bowl in a metal retaining ring. The later plastic Z8896 bowl is the same shape and will fit, so a glass Z8591 bowl and ring should fit a Z8896/Z8691

cool... all I got to do now is find some 8591's and stock up on 8691's to fit glass bowls to!

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Please reply North Yorks County Council.... we want your old lanterns.

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From streetlighting to radio, dance through the night whilst the streetlights are glowing outside.