wow 95CRI is quite impressive! I'm perfectly fine with 60 CRI though lol. I'm very light-skinned so the lower CRI fluorescent lamps make my skin look a little tanner (well more like yellower but it's better than looking like a snowman with a pinkish tone lol). I like the 5000K 87CRI GE sunshine lamps i bought but MAN i look like i had my blood drained from me when i'm under them lol. Right now they're not in use though. I still have the 3500K and 4100K GEs in my F40s (and the 34W Philips lamps in the garage)
wow that ballast sounds awesome! Did he let you keep it? Jefferson and Robertson made some really cool and unique ballasts and they were built VERY "tuff" lol. yeah the electronic slimline ballasts don't let the lamps striate which is good. I'd imagine they work the lamps harder too.
Yeah residential grade MV yardblasters tend to buzz like beehives themselves after year of service lol. A lot of the time though when a fixture is loud it's the fixture itself, not the ballast. Cobraheads are especially known for because the fixture is held shut by a latch, which is looser than a screw meaning the fixture vibrates. The door vibrates, the reflector vibrates, the refractor vibrates, and even the arm can contribute a little bit when it comes to noise too all from the ballast vibrating.
Yep all balalsts (well reactors and reactance ballasts, which are simple ones with no capacitors) will start off loud and high pitch and then tone it down a little. Once the ballast stays the same pitch and loudness the lamp is fully warmed up. Yeah my lights will do that when they're mounted on the stand inside my room but now otherwise. My guess is inconsistance line voltage. Ideally, HID lights should be on their own circuit (multiple HIDs can be on the same circuit but that circuit should ideally be designated for lights since other electronics or applicances can "pollute" the line voltage). The lamp is fine though. HID lamps will sometimes flicker randomly, i guess some are just less resistant to line voltage fluctuations.
Yeah the lifeguard lamps don't blacken as much as lamps without the special coating. try to peek at the arc tube and see if it's blackened at all. I have to say, even though the Sylvania Eco HPS lamps look like they're overdriven and i don't really like the yellowertint to it, they seem to be brighter and it's easier to see under them compared to other HPS lamps. I guess it's the same with their mercs. The /DX mercs are all pinkish but the light they emmit is superior to any other MV lamp.