How and Where to get Parts for Large Xenon Strobes

Updated slightly and partially cleaned up 7/8/2018, most stuff here is over a decade old.

Contents:

WARNING! Stuff discussed here can be dangerous. High voltages here can electrocute you. Most quartz flashtubes (and a few specialty glass ones) emit shortwave and mediumwave UV. Nearly all flashtubes emit longwave UV. Large quantities of different types of UV can burn/damage different parts of your eyes and different layers of your skin. Shortwave and mediumwave UV may be hazardous in not-so-large quantities. For a greater discussion of xenon strobe hazards and safety, Go Here!

Powerful Flashtubes:

My favorite abusable flashtube is the Speedotron 14570, also known as an MW8QV. This is the "plain quartz" (as opposed to color-corrected/reduced-UV MW8QVC) flashtube for Speedotron's "Black Line" model 102 flash head.

You can order this flashtube at some professional photo supply shops for approx. US$ 110 to 120. One such place is B&H Photo in New York City.
Web:
http://www.bhphotovideo.com/

This flashtube has a maximum rated flash energy of absolutely bigtime - 3200 watt-seconds. The flashtube works best at voltages slightly under a kilovolt. I would derate the quantity of energy proportionately with voltage below 900 volts, and not use this flashtube below 500 volts.

To make things easy on the flashtube's electrodes with heavily repeated flashing, I recommend a maximum amount of energy (in watt-seconds or joules) of 1,000 or 1.1111 times the voltage, whichever is lower.

As for minimum energy for efficient flashing - at least 100 watt-seconds, maybe 200.

As for maximum average power input to this flashtube? This tube can take a beating. In free air, it seems to handle up to 200 watts OK with flash energy between 200 and 1,000 watt-seconds and voltages of 700 to 1100 volts. Use less average power with other voltages and other quantities of energy, or if the tube is enclosed in something where heat will accumulate. This tube can be forced air cooled for more power handling. Connect a small vacuum cleaner to it, and it can probably take 600 watts long-term and a kilowatt for half a minute with favorable energy and voltage.

As a brief torture test of this flashtube, I have given it an average power input of 700-800 watts for a couple minutes with no forced-air cooling (but otherwise with better-than-usual ventillation), and couldn't ruin it. I just can't smoke it, break it, nor burn it. However, really prolonged really heavy use is known to discolor the quartz tubing. Should you want to exceed my recommendations and be able to tolerate some gradual tubing discoloration or you don't need extraordinary life expectancy, GO FOR IT. This tube can take a beating.

One thing about the Speedotron 14570/MW8QV: It triggers unusually easily. I have been able to consistently trigger this tube with 3 and 4 KV pulses from cheap trigger transformers. Please note that these trigger transformers want primary voltages around 300 volts, less than the flashtube wants. To work a cheapie trigger transformer from higher voltages, feed the trigger capacitor from a voltage divider instead of a resistor. For example, use 1 meg from the capacitor's positive lead to the positive point of the energy storage capacitor, and a 470K resistor from the capacitor's positive lead to the negative point of the energy storage capacitor.

As for maximum voltage, I recommend against going much over a kilovolt. I have known this tube to self-fire at 1600 volts, and inconsistently do this or not do this. This impairs some use of this tube for short-flash and enhanced-UV applications. This also impairs attempts to efficiently use this tube at low flash energy but with really high voltage to get xenon ion spectrum output.

A lower voltage serious flashtube is the Photogenic C4-5. This is the flashtube for the Photogenic "Powerlight" 1500SL flash unit. There is a UV-coated/color corrected version of this flashtube. This flashtube is available with either clear or frosted glass domes with a small hole in the top of the dome. Be sure what you are getting.
This flashtube works best around 400-550 volts. The minimum voltage for reliable flashing is 360 volts. It takes up to at least 1,000 watt-seconds, and should take 500 repeatedly and have a good life expectancy. I would derate the flash energy proportionately with voltage below 450 volts. It can take a 150 watt average power input, 200 watts for 1 minute. Both these can be increased by at least 50 watts with some forced-air cooling. I would derate these figures proportionately with voltage below 500 volts.

Avoid using more than 500 volts unless you want plenty of UV and a slightly more-blue-than-average color. Also this tube draws really high peak current (greatly exceeding a kilo-amp) at these voltages and can heat up capacitors that don't have really low resistance.

This tube needs more trigger voltage than the Speedotron one - I recommend 6 KV trigger pulses. It usually triggers at 3 KV, but I have found triggering below around 5 KV to not always be reliable.

This flashtube is also available at B&H, but costs a bit more than the Speedotron one - approx. US$ 134.

A smaller, truly compact but serious quartz xenon flashtube is the Lumedyne 090Q. It has a rating of 2400 W-S which I consider unrealistically optimistic. I believe it can take 1200 W-S occaisionally and 400 W-S heavily repeated with reasonable life expectancy. As for average input power, I don't yet know but think it can take 100 watts short term and 50 watts long term. I believe the voltage should be 500 to 700 volts.
This tube costs approx. $130. I recommend it only where the compact size of this tube is necessary. Otherwise, I recommend the Speedotron MW8QV / 14570 instead.

I have some technical info on some specific flashtubes in my Flashtube Ratings/Data/Specifications Page.

My material here on the Norman FT-6 was deleted on 7/8/2018 because of low availability and mediocre performance. It is still available in archived versions of this web page at the Wayback Machine, web.archive.org.

AN EVEN BIGGER OPTION FOR REPEATING STROBES!

Use one of those long flashtubes for photocopiers.

One way to get one: Find a copier with a flashtube you like. Note its manufacturer and model number. Go to a place that sells replacement parts for that copier, and order a replacement flashtube. Then, go to my Xenon Strobe Design Guideline Page to determine appropriate energy and voltage. Straight flashtubes generally do well with really high voltages that give good efficiency at lower quantities of flash energy - good for faster-flashing strobes.

Another way: The EG&G Heimann division, afterwards Perkin Elmer, now Excelitas JG7905 or JG 7905. It is about 57 cm. long, has an arc length of 49 cm, and is 1 cm in diameter. It is rated for gentle use, up to 200 watt-seconds and average input power up to either 180 or 260 watts, depending on when its manufacturer stated a maximum flash rate with 200 joule flashes. Such gentle use allows life expectancy of either 10 million or 15 million flashes, depending on when the manufacturer said this, with 15 million flashes being the more recent stated life expectancy.

This flashlamp can take greater flash energy and greater average power, at the expense of reduced life expectancy. It cannot take as much flash energy, flash charge in coulombs or average power as usual for quartz flashlamps of its size because it has smaller electrodes than usual for large quartz xenon flashlamps.

More technical details of this flashlamp (and some others I mention here) are in my flashlamp ratings and specifications page.

There are also the impressive linear flashlamps often used for laser pumping, such as ones from the former EG&G "optoelectronics electro-optics division". The Perkin Elmer catalog for those is with the Wayback Machine here.

Quartz linear laser pump flashlamps are available on eBay.

Big Capacitors

UPDATE 7/23/2011: What I like now is Vishay/BC Components ones of their 102 PHR-ST series, available at Digi-Key. I find their impedances and effective series resistances notably low.

There are the Vishay/Sprague "Powerlytic" 36DX series. These include some nice 450 volt capacitors available in 2000, 3100, and 3500 microfarads. You can get these from Allied Electronics and Newark Electronics. The 2,000 uF 450V ones cost approx. US$48, the 3100 uF ones cost approx. US$ 67, and the 3500 uF ones cost approximately US$74 in small quantities as of 1997 or so.
There are also 350 volt capacitors in this series, available in 1300, 3300, 3700, and 5100 microfarads.

Please note that the above electrolytic capacitors generally do well only with flash durations at least half a millisecond, preferably a millisecond. For shorter flashes likely with repeating strobes, I recommend laser energy storage capacitors or a bank of AC-rated motor run capacitors.

Easy ways to get 400 volts with fluorescent lamp ballasts.

Back up to my Xenon Strobe and Flash Page.

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Written by Donald L. Klipstein.
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