It is my understanding that SOX-E lamps can be run on SOX-E ballasts for lower brightness and enhanced efficacy, or on their SOX counterpart ballasts for higher brightness but more similar efficacy to plain SOX (probably lower lifespan too). Correct me if I am wrong but I believe these are the substitutes:
26W can replace 35W
36W can replace 55W
66W can replace 90W
91W can replace 135W
131W can replace 180W

They have identical or at least similar physical dimensions. On plain SOX gear, presumably they achieve wattage reductions by having a lower voltage, similar to energy-saving fluorescents. Of course this wattage reduction is accompanied by an efficacy increase simply due to the improved ITO coating. But I don't know if using a SOX or SOX-E lamp would yield higher light output on a SOX ballast.

What I am asking is what are the specs of these lamps when run on SOX ballasts? I have their specs when run on SOX-E ballasts, but obviously that's different. I'm mainly looking for electrical specifications but lumen output would be nice as well. Haven't had much luck looking for it.

Thanks!

If someone just has their RMS voltages I can sort of approximate the currents and wattages

if only there was a great archive of historical datasheets and catalogs that might contain the info your looking for

i'd highly recommend you check out the literature section on James's website, lots of juicy technical details in the various catalogs, technical data sheets and technical manuals that will answer many of your questions and I am sure you will find most fascinating (I have certainly lost many an hour to it in the past)

https://www.lamptech.co.uk/Literature.htm

if only...




page 167 (as per the PDF counter) 

https://www.lamptech.co.uk/Documents/Catalogues/Philips%20-%20Catalogue%20-%201989%20UK.pdf





the question I am wondering is why does the CCT change through out the wattage range, whats going on there!

@LightBulbFun
Definitely a good find, thanks. It only seems to list the wattages and not the actual current and voltage, but a reasonable estimate can be made assuming the total lamp power factor stays constant (definitely not the case but maybe close enough).

Using their power from that catalog, their equation constant "C" derived from their SOX-E ballast specs (not gonna be the same for SOX ballast but hopefully close enough), their total power factor (also taken from SOX-E specs, again not gonna be the same but hopefully close enough) and the rest of their specifications put into a system of equations following this structure:

ZBal = (C * √(OCV^2 - VLamp^2)) / ILamp,
(VLamp)(ILamp)(PF) = PLamp

where VLamp is x and ILamp is y, I arrived at the following approximations:

26W SOX-E on 480VOC 35W SOX ballast:
60V, 0.61A

36W SOX-E on 480VOC 55W SOX ballast:
79V, 0.6A

66W SOX-E on 480VOC 90W SOX ballast:
86V, 0.94A

91W SOX-E on 650VOC 135W SOX ballast:
101V, 1.13A

131W SOX-E on 650VOC 180W SOX ballast:
188V, 0.92A

These are values calculated for the reference ballasts, which are linear impedances at 480 and 650VOC respectively. As is the case for all lamps but especially for LPS, these reference ballasts are usually never what is actually produced. These values I have calculated are wrong until proven correct. Again if anyone has the voltages or currents for these lamps on SOX ballasts please do let me know.