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70w Thorn "not-sodium" SON-T I was given this NOS Thorn 70w SON-T lamp and it looks like it has never been used. When I tested it however, it appears to be defective as when the lamp is started on normal 70w SON gear, the lamp current sits on about 1.15 amps and the lamp voltage does not want to rise above 17v. I've tried it on 400w SON gear and while the lamp current is a lot higher, the lamp voltage still refused to rise. I even tried it on my high-voltage 1000w metal halide gear and even then, the lamp voltage only rose to 19v and it was puling about 7 amps from the ballast! It's worth noting that when it's being forced on the higher lamp current, the colour is very white. It does seem that there is in fact, no sodium at all in this lamp!

70w Thorn "not-sodium" SON-T

I was given this NOS Thorn 70w SON-T lamp and it looks like it has never been used.
When I tested it however, it appears to be defective as when the lamp is started on normal 70w SON gear, the lamp current sits on about 1.15 amps and the lamp voltage does not want to rise above 17v.

I've tried it on 400w SON gear and while the lamp current is a lot higher, the lamp voltage still refused to rise.
I even tried it on my high-voltage 1000w metal halide gear and even then, the lamp voltage only rose to 19v and it was puling about 7 amps from the ballast!

It's worth noting that when it's being forced on the higher lamp current, the colour is very white.

It does seem that there is in fact, no sodium at all in this lamp!

IMG_0451.jpeg 387A7501~0.JPG 387A5227.JPG IMG_0410.JPG 387A6133b.JPG
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Filename:387A5227.JPG
Album name:FrontSideBus / HID: High-Pressure Sodium
Filesize:3941 KiB
Date added:10 Apr, 2026
Dimensions:3072 x 2048 pixels
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URL:http://80.229.24.59:9232/gallery/displayimage.php?pid=24428
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dor123   [10 Apr, 2026 at 05:25 PM]
This is essentially a low pressure xenon lamp.
Liam   [11 Apr, 2026 at 04:51 AM]
No shock there tbh i don't think Thorn SON lamps lasted that well? I have one on test atm and after 2 years use it warms up white then goes pink.
Danny   [12 Apr, 2026 at 09:04 PM]
That’s interesting but it’s something I’ve come across before too! I have a 250w Philips that’s like this and I believe the new China Philips, some of them are known to be like this too

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