Information for the GE digital ballasts for CMH bulbs are in the links there, (e-ballast). However, looking over the spec sheets, it seems there isn't much of an advantage going with the digi ballasts for a CMH bulb.

http://advancedtechlighting.com/p-5497.pdf
there is the link for phillips
Swansen Reviewed by Swansen on . Ceramic Metal Halide - CMH data sheets welp, i've been looking around for a while, trying to make a decision but i didn't find anything posted anywhere like this, just bits and pieces. Unfortunately i couldn't find anything for Phillips.. their website is weird and their search feature was messed up, along with not linking much in their information pages.. Oh yeah, looking at the spectral diagrams from GE, it seems 4200k would be much better suited to plant growth. vV GE Vv Rating: 5