Thorn 400W CSI Compact Source Iodine metal halide lamp

I have always wanted a CSI lamp on account of their technical awesomeness

I was (still am!) looking for a PAR64 1000W example, but when this August 1973, Vintage Thorn 400W example of the original CSI design showed up for cheap I just could not pass it up :)

especially as I had only seen very few pictures of CSI lamps lit, I think the only ones being FrontSideBus's awesome photos of his 1000W CSI and CID PAR64 examples

so I was especially curious to see how the original 400W example would perform

and I have to say it was quite interesting and very impressive, it really struggled to strike at first on my 5Kv ignitor, but it eventually struck up from a glow discharge and it ran up very quickly indeed to a brilliant intense cool white light

its always impressive to see just under how much load they are under when running by how hot their are just after switch off, I think I have only ever seen glowing molly seals like this on CSI lamps,

for those wondering I ran the lamp using 600W SON choke with 210V being fed into its 250V tap, which gave me a nice 5A that the lamp is rated for :)