Halogen bulb light

[yann]

Today I have a Fender Super Twin Reverb 180W on the workbench that has been given to me for fix (keep blowing fuse).

So I have decided to update my bulb current limiter with a 150W bulb and what a surprise when I went to the shop and seen 90% of the lightbulbs were now LED based. The remaining stock was only low power stuff not very usable.
The vendor told me that in Europe, they have banned Halogen lightbulbs since 1st of September.
I was aware of such a project but could not imagine that these bulbs will disappear so fast from our shop...

It was hard to explain him why I specifically needed a really power consuming lightbulb, the guy was keeping telling me that I could have the same luminous intensity for less money of electricity

So now, it's time to make some stock of these bulbs... I had to order my 150W one on amazon, no way to find it in local shops here !

[rjb]

We have a similar situation in the USA. I stocked up before the ban on higher power incandescent bulbs.
But for some reason, they can still be found in some stores with "Dollar" in their name.

-rb

[Jazz P Bass]

We use incandescent (filament) bulbs in the USA.
I can't say whether or not a halogen lamp would even work as a limiter.

Why do you need a 150 watt lamp limiter to work on a tube amp?

Then again, I can't recall the last time I used a limiter on a tube amp.

[soundmasterg]

It was hard to explain him why I specifically needed a really power consuming lightbulb, the guy was keeping telling me that I could have the same luminous intensity for less money of electricity

Since the light bulb in the current limiter is in series with your amp and the AC supply, you need a light bulb that can be adjusted with a variac and that has internal resistance. Many LED bulbs can't be adjusted with variable power though they are getting more every day, but LEDs have very low internal resistance so they won't really function as a current limiter. When using a bulb with high internal resistance such as an incandescent or a halogen, if the amp has a short it will try to draw more current from the AC supply, but with the bulb in series, as the amp tries to draw more power, the bulb will get brighter and brighter due to the internal resistance of the bulb and the increased current draw of the amp.

Before the low power incandescent bulbs went away in the US I stocked up on a bunch of 100W, 60W and 40W bulbs. I haven't tried any halogen bulbs in my limiter yet, but I am sure they would work, though maybe not as well as a traditional incandescent.

Greg

[yann]

I tried to explain him how this was supposed to work but he looked at me like I was crazy ^^
Incandescent filament bulbs are no longer available here, that's why I went for halogen bulb.
Halogen is working fine for me, I usually use it with a 60W bulb but for the 180W beast I was thinking it was better to have a more powerfull one to avoid having it lighting when the amp drawing its nominal current. But I may be wrong

[Leo_Gnardo]

I tried to explain him how this was supposed to work but he looked at me like I was crazy ^^
Incandescent filament bulbs are no longer available here, that's why I went for halogen bulb.
Halogen is working fine for me, I usually use it with a 60W bulb but for the 180W beast I was thinking it was better to have a more powerfull one to avoid having it lighting when the amp drawing its nominal current. But I may be wrong

Looks like you hit on a sensible solution. Halogens should work fine in this application. They are filament lamps after all. So the filament is surrounded by some special gas instead of a vacuum, no big deal.

Although I rarely use my light bulb limiter, I have bulbs ranging from 15W to 250W to use depending on the expected power of the circuit I'm working on. For medium to high power solid state amp, I can start with a 40W bulb. Once I have the amp working, increase the bulb to 75W, make sure the amp works OK there, then 250W for one last limiter test before plugging the amp straight into the power line.

Anyone seeking a 250W lamp, look for a "heat" lamp. The shape will look like a big spot light bulb. It will glow orange-red instead of white, no big deal. Please observe the following caution when using such a large lamp for the test procedure. If the amp under test fails and the large lamp starts glowing full brightness, it gets very hot and could set nearby items on fire. Keep your eye on the test rig while it's powered up, don't step away for a cuppa coffee or something. Safety first.

[Enzo]

Incandescents are still made for specialty use. Things like rough service lamps, appliance lamps, heat lamps, spotlights. We don't care what the bulbs look like.

[glebert]

Would it work to wire a big power resistor is parallel with an LED bulb? Obviously less convenient to switch the limiter for different current draws, since you would need a different resistance, but it seems like it would still 1.) limit the current and 2.) light up bright if you have a shorted load.

[g1]

The beauty of the incandescent is it acts as a dynamic limiter. The bulb resistance increases as it heats. A fixed resistance will not give the same kind of protection as the bulb. This is also why they are used for tweeter protection.

[nevetslab]

The beauty of the incandescent is it acts as a dynamic limiter. The bulb resistance increases as it heats. A fixed resistance will not give the same kind of protection as the bulb. This is also why they are used for tweeter protection.

Very good point!

[Dave H]

The beauty of the incandescent is it acts as a dynamic limiter. The bulb resistance increases as it heats. A fixed resistance will not give the same kind of protection as the bulb. This is also why they are used for tweeter protection.

[eschertron]

Well, now I have my next album title...

The beauty of the incandescent