Old lamp holders

[mbthegreat]

I have just recieved two T-Spots and an old Silhouette, and upon inspecting them I found they had a type of lamp I have not seen before, a T11. This lamp, rather than using a bayonet style fitting, is a prong style fitting. Should I / Can I replace the lamp base for something with a bayonet style? Are T11s still made?

[Wuddy]

No need to change the lamp holder, T11/T19 1Kw lamps, GX9.5 base are readily available, .

[Ynot]

I have just recieved two T-Spots and an old Silhouette, and upon inspecting them I found they had a type of lamp I have not seen before, a T11. This lamp, rather than using a bayonet style fitting, is a prong style fitting. Should I / Can I replace the lamp base for something with a bayonet style? Are T11s still made?

My, you've led a sheltered life thus far! :o

But yes, they are indeed still available, and a pretty standard fare, as they fit (amongst others) modified patt 223's, and 264's and even Cantata's (down-lamped as they're 1200W as standard).

[Bryson]

T11s are directly swappable with T19. I'm not sure what the actual difference is - same lamp base, same power rating. (Is it in the curved vs straight envelope, perhaps?)

 

No, you shouldn't swap for a bayonet-style lamp - the T11s are newer and a better choice.

 

The T11 is very, very standard stuff. You'll see them in almost all 1K fixtures from the 1990s, and older lanterns that have been modified.

[mbthegreat]

Great, thanks.

 

I have indeed lead a sheltered life! I've only seen the bayonet style fitting and the old large round type lamps.

[JimWebber]

Great, thanks.

 

I have indeed lead a sheltered life! I've only seen the bayonet style fitting and the old large round type lamps.

 

I do apologise if I am teaching you to suck eggs here, and stating the bl**dy obvious!

 

If you have never seen a T11, or other Bi-Pin Halogen lamp, you are aware that you must not touch the glass envelope aren't you?

 

You can get away with touching the glass on T1s but don't try it on a halogen lamp!

 

If you already knew about this, then I will wind my neck in!

 

Jim

[Tomo]

And if you do accidentally touch the envelope, then you need to clean it with isopropyl alcohol wipes.

(This is not vodka!)

 

The reason for this is that halogen lamps run much hotter than normal tungsten lamps, and thus use quartz glass instead of 'normal' high-temp glass.

 

Fingerprints actually cause the quartz to turn white and soften, and then the lamp bursts!

They are also pressurised inside, so when they go there is a pretty loud BANG!

 

(I once saw a lamp that had a perfect fingerprint burned into the glass - I half wish I'd kept it as a curiosity)

[Ynot]

The reason for this is that halogen lamps run much hotter than normal tungsten lamps, and thus use quartz glass instead of 'normal' high-temp glass.

 

Fingerprints actually cause the quartz to turn white and soften, and then the lamp bursts!

They are also pressurised inside, so when they go there is a pretty loud BANG!

 

In fact, here's a T19 that some clever sod at my venue obviously mis-handled. They seldom go anything like this, but you should get the picture...! :o

http://i76.photobucket.com/albums/j40/Ynot_01/15-03-07_2256.jpg

[ianl]

T11s are directly swappable with T19. I'm not sure what the actual difference is - same lamp base, same power rating. (Is it in the curved vs straight envelope, perhaps?)

 

 

the T11 has the filaments on a single plain. the T19 stagers the filament between 2 adjacent plains. thus in the T19 although the filaments are still the same distance from each other, in the orientation of reflector to lense the filaments apear closer together

[mbthegreat]

I'm not so inexperienced as to not know to not touch the glass, I change lamps often enough.

[pscandrett]

(I once saw a lamp that had a perfect fingerprint burned into the glass - I half wish I'd kept it as a curiosity)

We had two Mac 300s that we bought secondhand and the two very dark 'UV' blue colour dichroics in them had very clear fingerprints etched into them, for what I guess is exactly the same reason. They weren't expensive to replace but it was really quite interesting; it is easier to put the colours into a mac with one finger on top and one on the bottom but it was a good illustration of why you shouldn't do that!

[johnhuson]

If you've only ever come across old style P28S base lamps (bayonet) with the large bulb shaped lamps (T1) you might like to try substituting the T1s for T28s which is a 500w tungsten halogen lamp on a P28S base. You'll find you gain a significant amount of light output from fixtures like Patt 23's which were originally used with T1s.

[mbthegreat]

we do use T28s in our old lanterns, but being a charitable theatre we often have old lanterns donated, sometimes with old lamps in them.

[Ynot]

Hmmm....

 

I'm not so inexperienced as to not know to not touch the glass, I change lamps often enough.

yet...

 

I have indeed lead a sheltered life! I've only seen the bayonet style fitting and the old large round type lamps.

...but...

 

we do use T28s in our old lanterns

You can see why we sometimes get confused.....

[mbthegreat]

T28 is a bayonet style fitting is it not? And if I'm changing lamps in a lantern stock that doesn't use any T11 style lamps, I'm unlikely to have seen one before.