Paul C. Buff, Inc. Technical Forum

I wonder if you can give me any suggestions on what type of LED bulb might work as a modeling lamp for my old WL5,000 and WL10,000 strobes (which, despite their advanced age, still seem to work and don't seem to have lost any power capacity).

I tried a dimmable 75w-equivilant LED bulb yesterday. It screwed in fine and there were was probably slightly MORE clearance between the led bulb and the flash tube than with a 60w incandescent.

However, once I pushed in the switch for the 1/3 power capacitor, the strobe immediately started firing repeatedly.

I replaced the LED bulb with the 60w incandescent and tried again and the WL5,000 was back to normal operation.

So as far as anyone knows, is there something I should look out for next time I go shopping for an LED Bulb for a modeling light?

I am almost certain that I have in the past (about 6 months ago) tested a different LED bulb as a modeling light and it worked fine. I sadly don't know what happened to that bulb though (I think my wife took it and used it someplace... who knows???) So I am assuming that LED's CAN be used in general, right?

A couple of things come to mind. First, depending on the iteration, the LED could be setting off the slave eye, which is in the front in some 5,000's. This could be from the intensity of the light or from the blinking that is inherent in LED's, or both.

Also, some things to factor in is whether or not the slave eye is being locked out. Generally plugging in the sync cord does the trick, but sometimes you will have a quirky light that wants to be turned off first.

Given the age of the light, we have not done extensive tests with LED and the 5000 or 10000's, but I do not anticipate a general problem with LED use, though one bulb to the next may give different results.

Thanks so much, Tech Support!

Yeah, my 5,000s and 10,000s always had a sensitive optical trigger (in a good way!!!) so I wonder if that is it?

I can try plugging a plug into the sync jack FIRST (because I usually trigger them with a wireless trigger) and see if that stops the problem from happening. (When I first tried it out, I DIDN'T have a sync plug inserted into the jack.

Thanks again for all your help.

No problem. Please post back if you can isolate it to the slave eye.

Well, I am happy to report that plugging in a 1/4 mono plug into the sync jack on the back of the strobe cured the constant firing.

Plugged it in, and the strobe worked fine.

Unplugged it, and the strobe fired continuously.

Plugged it in again, and it worked fine again.

Unplugged it again, and it fired continuously.

Pretty sure this mystery is solved.

I am using a 10 watt (60 watt equivilant) dimmable (atenable) LED that is marketed under the brand TCB.

The one I am using is an "A19" shape bulb, since that is shaped like the "classic" standard light bulb.

I don't see any other distinguishing features that differentiates it from other LED bulbs one might buy at the local hardware store. But I am pretty certain that one would need a dimmable / atenable style bulb.

Hope that helps.

Thanks for the feedback. I will keep it in mind for the future.

Thank You.

BTW: As you are probably aware, the WL5,000 / 10,000 series have the modeling light power tied to the actual flash power.

Since I was using my WL5,000 up close at 1/3 power, the modeling light was (effectively) only 20 watts, since I was using a 60-watt equivalent LED bulb.

Needless to say, my models' pupils were HUGE.