HPL 575 or 750 in your Source4?

My 750 watt lamps have an extra post (for stability?) that are not on the 575's. My S4 lamp housings have a socket for this piece but the pair I just rented did not. I ended up lamping one at 575 and had a spare lamp housing that I put on the other fixture. Is this common?
 
My understanding is the post is there to prevent the installation of 750watt lamps in caps that are not rated to that capacity, such as the junior units.
 
My understanding is the post is there to prevent the installation of 750watt lamps in caps that are not rated to that capacity, such as the junior units.

Thats exactly the reason, The 575 watt caps without the extra prong hole cannot handle the extra wattage so to make sure there wasn't issue with users putting a 750 watt lamp in a 575 unit they added that prong. Also you can put 575s in 750s no problem. Just the other way around is the issue.
 
We use mostly HPL750 because we never have multiples on one dimmer and our FOH positions are about 50 feet from the area they need to hit. We do burn through gel's quickly, but we also have a stock of gel shields for scrollers and other long lasting units, and we have a bunch of 575s in storage. Just thought another example might help.
 
One thing to keep in mind when it comes to burning through gel is that by properly benching units and properly adjusting beam focus gel life and lamp life will be enhanced (more light passing out the front of the unit rather bouncing around in it and being converted to heat there). Additionally, one can also use a pounce wheel to create "vent" holes in the gel that will allow additional heat to pass through them. A little time consuming, which is why I assume most people don't use the technique (have others had the luck with it I have had?), but in long term installations where a gel extender isn't available or is impractical it can help.
 
575 in all the S4 and S4 PARs.
Flexibility is important as we seldom do the same thing twice.
 
One thing to keep in mind when it comes to burning through gel is that by properly benching units and properly adjusting beam focus gel life and lamp life will be enhanced (more light passing out the front of the unit rather bouncing around in it and being converted to heat there). Additionally, one can also use a pounce wheel to create "vent" holes in the gel that will allow additional heat to pass through them. A little time consuming, which is why I assume most people don't use the technique (have others had the luck with it I have had?), but in long term installations where a gel extender isn't available or is impractical it can help.

I was taught to vent gel in my Roscolene days in the 70s. Guys coming out of school these days look at me like I am crazy when I do it. I always vent with a pattern cutter.
 
I was taught to vent gel in my Roscolene days in the 70s. Guys coming out of school these days look at me like I am crazy when I do it. I always vent with a pattern cutter.

Probably less effective now as the Source 4 transmits much less IR and converts much less of it to heat at the lens. I'm only 24, but I was taught to do it when working with the 360Q's Temple U. kept for student produced shows when we did a series of 4 shows in Rep. With a budget of $0 for lighting, we needed to make the limited supply of cool colored 7.5inch cuts last (not easy when undergrad directors keep yelling brighter).

That is another reason for using 575's... brightness is relative (though there is a certain point at which our eyes receive too little light to allow our brain to perceive what we are looking at clearly). If you base everything off of 575watts, if you really need a unit or units to be brighter than the rest, you can lamp them up to 750 watts. Or you can switch from a long life lamp to a standard life. As long as you remember to switch them back when done......... ( I once got a rental package of S4's with everything except a 375 HPL in it, say what?)
 
....... i'm noticing that a good portion of the deep saturated colors don't come in a high temp version... and end up burning through the gel about half way through the show.......

Just thinking about when I broke into the biz. Gel was GEL. Colors like Special Lavender (similar to the current Rosco R54) had to be replaced nightly in a musical. Pre-show check was not only to check for burnt out lamps, focus position (did a lamp get bumped by moving scenery or crew. Especially important with shin busters or side lights low enough to be hit by side stage scenery) but also what color needed replacing that night. The lavenders faded very fast, the blue dye burning out leaving a pink color if not replaced. Light tech rooms did not have a file of used gel. There was no such thing then. Used = faded.
 
For a 25-35 ft. throw, 575W HPLs are definitely the way to go. 750Ws are best in larger spaces, in terms of lumen output.
 

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