ooh I like these. I've got one in colour 84 (840) and quite a few newer ones. *All* of mine appeared to be contaminated, especially the older one which was unused, it needed lots of persuasion with a glow bottle starter before it stayed lit and then took ages to clear up. Might be worth giving these a good run for a few hours once in a while to keep them 'fresh'

Very nice, these have a rather unusual etch!

I had no idea these were made so early, 1985 is old for an electronic ballast. I have the Sylvania Syltronica equivalent tube from 1988 and thought that was one of the first but obviously not. By the way, they are actually neon filled, hence the starting difficulty. They were intended for use exclusively on an electronic ballast and will be destroyed on magnetic gear (the 5' 50W argon at T8 tubes have quite different electrical characteristics).

interesting Neon filled would mean these would have quite a high voltage drop (as if the 50W Argon T8s did not already LOL), I assume the HF gear offsets the life lose of having a neon buffer gas? what is the exact electrical specs of the HF 50W T8? from what I recall it was quite close to that of a classic 50W Argon T8. (Current and voltage wise at least)

I had to start one on SS as it was badly contaminated and wouldn't strike on HF. I only use them on HF otherwise. I did read these could be used on the old 50w SRS circuits but no idea how correct that is. I'd love to know the electrical specs of both tubes?

a Quick google around for a Data sheet later shows that the Philips HF 50W T8 has a current of 355Ma and a voltage of 142V which is quite close to that of an original SRS/SS 50W T8... I do find it hard to see how such a tube would get destroyed on magnetic 50W T8 gear