I'd assume if you were to proportion the size of the inner tube just right and add a quarts halogen lamp and an internal ignitor it'd be possible to manufacture a self ballasted SOX?

Thoughts? Technical explainations very much welcomed.

Apparently it was tried by Philips using CFL electronic ballast technology, but never went into production?

I'm thinking more along the lines of the same principle used in self ballasted mercury lamps... However that is neat that they attempted it with a cfl type ballast.

Normally the SOX need higher OCV than a resistor could provide, so would need very low arc voltage, so very low ballast efficiency. Plus with all the losses there would be no reason to go for such expensive lamp, when other light sources with comparable efficacy offered way better color.

I tried to make a "compact low pressure sodium lamp" (mine was more along the lines of a PL adapter) using a spent CFL for the ballast with a bayonet socket in place of the tubes and an 18 watt lamp. Whole thing was as long as a 35 watt LPS and the "lamp" section stuck out the bottom of the fixture I tried it in.

That's pretty cool. How well did the CFL ballast drive the lamp?

I would love to do stuff like that and actually make samples if I have the equipment and supplies for it. That SOX adaptor looks neat, I would continue looking into that more. I'd see about taking out the ballast from the base and try to make it more compact with the lamp

I would love to do stuff like that and actually make samples if I have the equipment and supplies for it. That SOX adaptor looks neat, I would continue looking into that more. I'd see about taking out the ballast from the base and try to make it more compact with the lamp

With SOX thar would be a problem: You need to not obstruct the light out, the discharge tube needs to be in thermally insulating vacuum, but the electronics needs good cooling. With all that limitations you dont have much other possibilities than cram the ballast into the base...

I tried to make a "compact low pressure sodium lamp" (mine was more along the lines of a PL adapter) using a spent CFL for the ballast with a bayonet socket in place of the tubes and an 18 watt lamp. Whole thing was as long as a 35 watt LPS and the "lamp" section stuck out the bottom of the fixture I tried it in.

That looks like something I wouldn't mind trying. What type of base/ballast did you use..? I have an 18W lamp but no ballast at the moment.

I tried to make a "compact low pressure sodium lamp" (mine was more along the lines of a PL adapter) using a spent CFL for the ballast with a bayonet socket in place of the tubes and an 18 watt lamp. Whole thing was as long as a 35 watt LPS and the "lamp" section stuck out the bottom of the fixture I tried it in.

That’s nifty nice job!

That's pretty cool. How well did the CFL ballast drive the lamp?

That looks like something I wouldn't mind trying. What type of base/ballast did you use..? I have an 18W lamp but no ballast at the moment.

The ballast I used was the one in the CFL (a 20 watt SunPark Electronics) It under-drives the LPS lamp though to maybe around 80% of it's nominal output and took about 18-20 minutes to "warm up". I've also ran it on as little as a 13 watt CFL which took nearly 30 to warm up. A board from a 25 watt CFL warmed up faster but slightly over drove the lamp. I'll have to try a 23 watt CFL. The electronic ballasts on all the CFLs I used have a capacitor across the electrodes where a starter would be in a preheat circuit. I just shunted both ends together so the start capacitor would be in parallel to the LPS bulb. Base is a Kulka model 5110 BY22D socket.

Note: I later blew this ballast out by attempting to run a 20 watt mini metal halide lamp. Lit for a second then the poor thing made a popping sound, shot sparks out the vents, and let out a bunch of nasty smelling smoke.

The ballast I used was the one in the CFL (a 20 watt SunPark Electronics) It under-drives the LPS lamp though to maybe around 80% of it's nominal output and took about 18-20 minutes to "warm up". I've also ran it on as little as a 13 watt CFL which took nearly 30 to warm up. A board from a 25 watt CFL warmed up faster but slightly over drove the lamp. I'll have to try a 23 watt CFL. The electronic ballasts on all the CFLs I used have a capacitor across the electrodes where a starter would be in a preheat circuit. I just shunted both ends together so the start capacitor would be in parallel to the LPS bulb. Base is a Kulka model 5110 BY22D socket.

Note: I later blew this ballast out by attempting to run a 20 watt mini metal halide lamp. Lit for a second then the poor thing made a popping sound, shot sparks out the vents, and let out a bunch of nasty smelling smoke.

You can't go around letting the magic smoke out of things.!!