I just got done with an installation of new Venture 350w uni-form pulse high bay fixtures, these fixtures include this lamp;
http://www.venturelighting.com/LampsDataSheets/PulseStartMetalHalide/71329.pdfand the matching Venture 350w pulse start HX-HPF magnetic ballast.
One interesting thing I noticed is that these lamps have an extremely fast run-up for a quartz lamp on magnetic gear, I clocked 50 seconds from initial cold start. Also it appears that Venture uses some sort of emissive coating on the electrodes like mercury lamps as they do not glow incandescent on start up. When started, the lamps look exactly like a mercury lamp with no electrode glow at all, there is no pink argon flashes, just an instant, stable mercury discharge. And the halide salts start vaporizing 20-30 seconds in, another 20 seconds and the lamp is at full output. How is this possible with magnetic gear. Venture must be doing some proprietary thing that other lamp manufacturers dont know about. Also there is no end paint on the arc tubes, very unusual for a Na-Sc lamp. The ballasts are dead silent too, I had my ear within 1" of the ballast box while it was running and I couldn't hear any hum, was truly silent. Unfortunately there were no extra lamps or fixtures for me to take home to test/experiment with.