If the wad of production budget was as it would seem spent on costumes, and I take it by the way this was presented you don’t agree with this, due to your concerns about replacement lamps or having enough lights for the show; perhaps nothing will
settle the problem for your distribution of the budget on future shows better than having half the
stage go dark but some darned fine costumes on
stage. Seems like your production crew needs most to work on getting itself people that can sew.
Granted this thought of letting it happen is not fair to the production at
hand, but you using your own money to solve the problem is certainly not the solution either. Do not rent, put your own money into or make home made equipment for shows no matter how simple the solution might seem. Realize that should something go wrong there could be more problems than just the lights going out. We are talking both the production’s and possibly your parent’s liability in addition to the cash you laid out for something that is part of the production expenses. You must keep your own cash separate from that of the production, it while seemingly a simple and easy solution is not a good one for you or your program. Trust me, it’s a bad habit to get into.
Do what you can as you should already to have a backup plan ready for during a scene such as someone that knows that if the
stage goes dark, they hit the
house lights or something like that if your production can’t afford to re-lamp with new lamps in insuring they hopefully won’t go out. Given your production is already buying four lamps, short of a electrical problem, you will already have at least four fixtures you can depend upon working. As you say, you will make the best of it and that’s about all you can do for now.
So a question now. If you are renting from this church, I assume that the lights you are using are part of the rental package. Given the fixtures belong to the church and are being rented to you in a condition that works for the length of your rental, why are you buying lamps much less worried about buying extra ones?
In any case, I expect we all understand already about the choice in beam spreads with the more expensive
PAR lamps and that they would be preferable for design purposes - just not available. While some ray light lamps are available in wider beam spreads, their use is less common because the ray light lamp has nowhere near the life of a
PAR lamp. 75 hours verses 2,000 hours. What makes ray light lamps seem cheaper to initially
purchase and use in fixtures by way of replacement bulbs is in reality a very expensive alternative in the long run. Unfortunately it’s not something that most sales people will advise in making the sale of more fixtures over more expensive ones on start up cost.
Given about an approximate price of $25.00 for a
PAR 64 lamp lasting 2,000 hours at 120v, and a DYS at say $6.50 each but only for 75 hours at 120v, the Cheaper in start up cost DYS lamp will cost $173.00 in gaining the same amount of lamp life as one $25.00
PAR lamp. Might present this figure to the church.
As an alternative to just replacing the lamps in the fixtures with the same lamps, given your production is buying them, I would recommend your production either buy
PAR lamps, than perhaps keep them for use on your productions, or start buying some DYS/5 lamps which should be about the same cost as a normal DYS lamp. The only change to the in theory 500 hour lamp is that instead of 120v, it’s rated for 125 or 126 volts in further extending lamp life at the cost of
intensity and output. I don’t have pricing on these lamps but normally if it’s only a change in the
voltage rating the price stays the same. Perhaps for next production, the lighting budget can be given say $100.00 to
purchase four lamps for use in your productions. Might be a reasonable enough thing to ask for.
Note, this is given the
PAR 64 fixtures have lamp bases that will hold a
PAR 64 lamp
base. The newer styles of ray light lamps have the same
base on them, the older ones only had
wire leads on the rear of the ray light
reflector and such cans would not have the lamp
base in place for you to install a
PAR lamp into.
1.
Mayhem has a important
point about the unpredictability of estimating lamp life when under the control of a
dimmer or even
line voltage when it’s different than the rated
voltage of the lamp.
For every 1% difference change below the rated
voltage of a lamp, it’s life is extended by 13%, it’s output is decreased by 3.6% and it’s
color temperature is decreased by 0.4%. These factors are inverted with over voltaging instead of dimming.
In other words, if you take a standard DYS lamp, given each individual lamp will have it’s own individual closeness to the specification, it will last on average 75 hours, have a
color temperature of 3,200°K and output of 17,000 Lumens. Especially dependant upon brand to brand comparisons, black sheep of lot numbers, and one lot number to another will also alter these average figures.
Given four lamps, dim lamp one by 50%, lamp two by 25% and lamp three not at all from it’s rated
voltage of 120v and you already have lamp one expected to last 487.5 hours, lamp two to last 243.75 hours as opposed to lamp three still equaling 75 hours. In the same respect however, lamp four the 500w
PAR 64 lamp would last 13,000 hours at 50%.
These rates the lamp is dimmed at is however during shows constantly changing along with other factors onto them such as
dimmer trim levels,
voltage spikes and even cold start turning them on than off. Once you change that
dimmer ratio, you completely
throw off the expected life again into something almost approaching random but at least say six times the expected lamp life. - My guess.
Also since it’s on a
dimmer, the
voltage at the
fixture will only rarely be at the 120v given this is the
power feeding the
dimmer. Factors like
voltage losses due to the
dimmer and
voltage drop will in most cases
drop the
voltage from two to ten volts. This lamp is rated for thus 75 hours at 120v, but given a at full
power to the lamp being 118 volts, it’s already at about 125 hours in life even if left on full.
Get confusing??? There is other factors still including bad lamp bases, dirty lamps
etc that will also
effect lamp life.