Moving inventory from 575w S4 to 750w?

flamingo

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Hi folks - I have 2 spaces with a significant part of both inventories made of plain ol' incandescent, standard-size S4s. Currently, the larger of the spaces is stocked with 575w lamps. The smaller space is 750w, but that may originally be due to the longer throw from FOH. I am considering swapping over to 750w for our larger space.

Several designers have mentioned how dim the lights look. Others have simply opted to lamp up entire systems from the get-go. Because of that, we do have a healthy stock of 750 lamps. I definitely wouldn't toss our 575w, we have a black box with juniors that can use them up eventually. We've put in some elbow grease for maintenance, but those that came before us didn't seem to have the time for the most thorough cleaning so I feel like we're climbing a mountain on that front. After using "clean" lights in a short student show, I tend to agree that the lights seem a little too dim. The last thing I know I still need to check is that we have enough 750 caps, I think we have enough for about 2/3 of our bodies but I'd like to have more confidence.

I'm trying to consider possible issues to make a pro/con list - has anyone done something like this?
 
Depending on the age of your fixtures, I can tell you that 750w burners are not compatible with older gen 575w bodies. I don't know about the later models or after they released the 750w fixture though.
 
Some OG Source Fours won't take a 750 lamp cap, and, as you mentioned, S4 jrs don't want to be lamped higher than 575w. You should also check any S4 PARs, PARnels, or Fresnels in stock.

Realistically, the price of LED profiles keeps dropping, and there's a healthy second-hand market for used ColorSources / Lustrs that I'd invest my energy (and $) that way, but ymmv.
 
Besides wattage, one also has to choose between "standard" (115v) and long-life (120v). So you actually have FOUR lamps from which to choose. Measure the socket voltage in a couple of different hanging positions in each venue to help decide. The easiest way to do this is to insert a twofer just before the fixture, and, with the dimmer/channel at Full, measure voltage at the empty female.
 
If your S4 can take the 750w then I think it is better to do that because you can always dim them down but never get more output from a 575w when it is at full.
 
Besides wattage, one also has to choose between "standard" (115v) and long-life (120v). So you actually have FOUR lamps from which to choose. Measure the socket voltage in a couple of different hanging positions in each venue to help decide. The easiest way to do this is to insert a twofer just before the fixture, and, with the dimmer/channel at Full, measure voltage at the empty female.
What Derek said. Check the voltage at the fixture, your perceived dimness could be a result of low voltage. There are some solutions to that---let us know the results.
And please use a true-RMS-responding meter to make the measurement.

ST
 
I switched to 750 long life's, not quite as bright as the full 750's but a huge upgrade over the 575s. I have never regretted it. You can always turn the 750 down. I typically run them around 75% which just adds to the life.

And also I'm another volt for confirming your house voltage matches your lamp voltage before you do anything.
 
At my prior venue I swapped to 300hr 750s after converting maybe 70% of the rig to LED. The additional energy was way offset by the LEDs so I didn't feel irresponsible in that way, lamp life could be lengthened a lot with a little dimming, and had the cleanest, punchiest white to cut through LED when needed. I'm a fan of that higher color temp and maximized output, especially if competing with LED. But the particular use case matters; if you lamp too bright so are always dimming way down, then the red shift is always keeping you from seeing a clean gel color. I'm a fan of the 300hr lamp color though, at any wattage. I've never felt like I'm replacing lamps so much more often than when I ran long life versions. Just match the wattage to your needs so you're balancing the need for more output with the need to not dim into too much red shift. If running 575 long life now, compare that to the 300hr 575, which is a considerable boost in output and perceived brightness because of the color temp. Might be enough, or might truly want the 750.
 
Besides wattage, one also has to choose between "standard" (115v) and long-life (120v). So you actually have FOUR lamps from which to choose. Measure the socket voltage in a couple of different hanging positions in each venue to help decide. The easiest way to do this is to insert a twofer just before the fixture, and, with the dimmer/channel at Full, measure voltage at the empty female.
Each wattage has the 115/120v (or 230/240v) choice to match house voltage (or not, and get more/less life and output on purpose), and also each voltage has a 300hr, higher color temp version, and a long life 1500-2000hr, lower color temp version. So in the 575-750w range there are EIGHT to choose from, oh my!
 
Rental stock, not a house plot, but we stick with all 750w/120v lamps as standard. Especially these days, people aren't ganging up fixtures like they used to, and it takes a lot of power to compete with LED and arc sources.

Don't get me wrong, I have giant backstock of 575 and 375 lamps for the people that request them. They're just not what lives in the fixtures. Having a single lamp, if possible, can make maintaining your inventory and stock levels a lot easier.
 
If you are going to upgrade to 750's I would use standard life (300hr) lamps. You will get the most punch from those. See the attached ushio pdf for hpl lamp comparisons.

I switched to 750 long life's, not quite as bright as the full 750's but a huge upgrade over the 575s. I have never regretted it. You can always turn the 750 down. I typically run them around 75% which just adds to the life.

And also I'm another volt for confirming your house voltage matches your lamp voltage before you do anything.
The 750w long life is brighter than the 575w long life, but technically not as bright 575w regular. According to the Ushio pdf, their 750w long life's initial lumens are actually 120 lumens less than a 575w regular lamp. I am also not a fan of the long life color temperature. To my eyes my 750w long lifes look more than 120 lumens dimmer than my 575w regular because the color temp is lower.
 

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If you are going to upgrade to 750's I would use standard life (300hr) lamps. You will get the most punch from those. See the attached ushio pdf for hpl lamp comparisons.


The 750w long life is brighter than the 575w long life, but technically not as bright 575w regular. According to the Ushio pdf, their 750w long life's initial lumens are actually 120 lumens less than a 575w regular lamp. I am also not a fan of the long life color temperature. To my eyes my 750w long lifes look more than 120 lumens dimmer than my 575w regular because the color temp is lower.
I should clarify, my theater was originally 575 long life's. So 750 long life's are a great upgrade. I can't afford the 300 hour life on 750 standards even with my budget. I'm not relamping the whole theater twice a year!
 
Just to clarify- unless you are running the fixtures at 100% intensity AT ALL TIMES, you will get far longer than the rated 300 hrs. avg. life. That is the average lifetime of lamps when run at FULL, 120 minutes on, 10 minutes off. If you dim them at all during their use, or run them at 95% or a little less, you will get double to triple that life (or more). So don't get scared off by the 300 hr. rating of the higher output lamps. TH lamps get FAR longer than their average rated lifetime in Theatrical applications because they are frequently dimmed and run at less than full voltage.
 
Just to clarify- unless you are running the fixtures at 100% intensity AT ALL TIMES, you will get far longer than the rated 300 hrs. avg. life. That is the average lifetime of lamps when run at FULL, 120 minutes on, 10 minutes off. If you dim them at all during their use, or run them at 95% or a little less, you will get double to triple that life (or more). So don't get scared off by the 300 hr. rating of the higher output lamps. TH lamps get FAR longer than their average rated lifetime in Theatrical applications because they are frequently dimmed and run at less than full voltage.
And when you normally only run your HPL long life lamps around 75% you get crazy long life span. :dance:
 
And when you normally only run your HPL long life lamps around 75% you get crazy long life span. :dance:
Truly, like so long that with lighter use like academic theater the filament/envelope are not what fails, but the cement holding them in the heat sink. I'm replacing lots of long life lamps for this reason lately, not usually because they don't work but because they shower dust inside the fixture. Clean a fixture, lamp tests good, re-assemble, bench focus, wait what's that all over my perfectly polished lens?! Some of these lamps may be original to the 20y/o building. A sheet of gel is close to $10 now and gets consumed in a matter of hours or even minutes. An HPL is about $15. How many years do we really need to squeeze out of it?
 
We used to use standard life lamps - in the last 10 years I don't think every lamp in the rig got replaced, maybe a third of them, and these are fixtures that get regularly derigged and moved.
 

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