Use a 750W bulb in a 575W Fixture?

A 575W Source Four unit is only UL tested and certified safe for a 575W lamp and lower.

mmeskill said:

A 575W Source Four unit is only UL tested and certified safe for a 575W lamp and lower.

As well, the 750w lamp has a third pin specifically so it cannot be used in a 575w rated fixture, whose socket does not accept the 750w lamp, so simply buying the lamps will not work.

There has however, been talk across the forums over the years as to whether a 575w fixture can be UPGRADED to accept a 750.  Besides the socket, the lamp cap is different, so that might need a swap out, but as question to ETC folks, what else, *if anything*, is required to upgrade the 575w fixture ?.

mmeskill said:

A 575W Source Four unit is only UL tested and certified safe for a 575W lamp and lower.

As well, the 750w lamp has a third pin specifically so it cannot be used in a 575w rated fixture, whose socket does not accept the 750w lamp, so simply buying the lamps will not work.

There has however, been talk across the forums over the years as to whether a 575w fixture can be UPGRADED to accept a 750.  Besides the socket, the lamp cap is different, so that might need a swap out, but as question to ETC folks, what else, *if anything*, is required to upgrade the 575w fixture ?.

Good question Steve. I'm fairly sure you can buy and replace just the end-cap of a S4. So no need to get a whole new unit. We will see if someone else jumps in otherwise I'll ask around at work tomorrow.

There's actually a Wiki article on this topic.

Thanks Matt !.

SB

Thanks for the reply Mike.  I'm sure you've figured out by now that I'm in the beginning of the learning process of stage lighting but I'm trying to learn as much as I can. I'm a volunteer at a community theater and their lighting person moved on and I'm the only one who is willing to try and light the shows properly. I really appreciate your help. The theater is a 420 seat proscenium stage house. We have a 96 channel board and dimmer with two catwalks over the house and three light bars over the stage with the upstage bar used for cyc lights. We have about 45 S4 ellipsoidals, about 20 750w and the rest 575w. We also have 10 S4 750w pars and 10 or so old fresnels. Our stage is approx 50' wide. I'm trying to set up a basic area lighting plot to illuminate the entire stage and can't seem to get some areas bright enough. I'm trying to use 2 front lights (one warm and one cool) at 45 degrees and a white backlight from the stage electricals. 

Thanks Steve, appreciate your help. 

Bill,

I think it might be easier if we have a quick chat. Where are you located and at what time might you be able to have a phone call? I'm in USA Central Time Zone and would be happy to talk with you today or during this weekend. Let's setup a time and get me your number and I'll be happy to give you a call. You can mail me directly at mmeskill@etcconnect.com.