8mm Forum: Pathe Baby Lamp Conversion

This is topic Pathe Baby Lamp Conversion - Both LED & Halogen in forum 9.5mm Forum at 8mm Forum.

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Posted by Janice Glesser (Member # 2758) on July 10, 2014, 08:23 PM:

I've been working on getting the right components to do my lamp conversion for a long time. I finally got my prototype set up and it appears successful.

I set up the test on my spare-parts Baby. I was able to get both a 12V 10W Halogen or a 12V 3W LED bulb to work with same power source. The 3W LED is suppose to be equivalent to a 20W Halogen, however it doesn't appear that bright to me. After testing it with film I'll see if I need a brighter LED. The bulb adapter I purchased from Martyn Stevens in the UK. This is a nice adapter that fits into the original lamp holder...so it doesn't require any modification to the Baby.

Here is the basic setup.

Here's the Halogen Bulb G4 Base

Here's the LED Bulb

Next step I'll set up my working Pathe Baby and test projecting film.

[ July 10, 2014, 10:24 PM: Message edited by: Janice Glesser ]

Posted by Dominique De Bast (Member # 3798) on July 16, 2014, 07:05 AM:

Have you tried with a film, yet, Janice ?

Posted by Janice Glesser (Member # 2758) on July 16, 2014, 10:40 AM:

Hi Dominique...I haven't tested this with film yet. I'm hoping to get to it this week. I've been corresponding with Ron Ashton who makes the replacement shutters. Being an engineer, he's very concerned with safety and the overall performance of LEDs. The modern LEDs were not designed for projection and may not disperse the light correctly. The halogen's perform closer to the original bulb. He's also mentioned something about lack of heat sink and that the LED bulbs may not last as long as intended. Ron has ordered the same LED bulb I did and will also be testing on his conversion setup.

I should be able to report my results shortly.

Posted by Dominique De Bast (Member # 3798) on July 16, 2014, 12:09 PM:

Nice, Janice ! Safety is important, indeed. We are so used to modern "secured" machines that we forget sometimes that 90 year old projectors have their electric wires sometimes close to metallic parts. Also, as I mentionned it in another thread, the first Pathé Baby had a strong heating on their base, hence the Pathé Baby carpets designed to protect the table or any support on which the projector was set.

Posted by Janice Glesser (Member # 2758) on July 21, 2014, 12:14 PM:

Well Dominique...and to any other readers...I tested with film yesterday and was not impressed with the results. The 10W Halogen was just not bright enough. The original bulb was brighter. Perhaps this just means I need a 20W...however, I'm concerned about burning the film. As far as the LED...it was brighter than the halogen...but still not as bright as the original bulb...and the light was not dispersed evenly. It was brighter on the edges and darker in the center.

There are different LED bulb designs I'm going to try that might give a more even light. I'll report back.

Posted by Dominique De Bast (Member # 3798) on July 21, 2014, 02:00 PM:

Sorry to hear you were disappointed. 10 watts is indeed weak, so you cannot except much but if it was darker than the original bulb, I can imagine how it lookled like. I have Pathé projector converted (not by me) to halogen. It is not a Pathé Baby model but a projector designed also for notched films. I don't remember what the voltage is (but I would be surprised if it would not be higher than 10 watts) and as I am on holiday until the 29 th August, I am afraid I cannot give you the information before. Pathé made a model called Pathé Lux (lux meaning light in Latin) that, if I am not mistaking, accepted three models of bulbs. One was the same as the Pathé Baby, the two others (hard to find now) were more powerfull, among these two lasts, one was intended only for "long titles" films (without notch).

Posted by Janice Glesser (Member # 2758) on July 21, 2014, 02:48 PM:

I saw a video that Dino made comparing his halogen conversion to the original lamp. The halogen was much brighter. I don't recall if it was a 10W or 20W. I'm going to get a 20W and see how it does with the notched films.

As far as the LED...I'm going to continue to experiment with other bulbs. I think the round type might give more even lighting then the long type I used. I just need to find one with higher lumens.

Found this one... http://www.lightinthebox.com/g4-4-5w-9x5630-smd-400-430lm-6000-6500k-natural-white-light-lotus-shaped-led-spot-bulb-12v_p479704.html?pos=ultimately_buy_1

[ July 21, 2014, 08:39 PM: Message edited by: Janice Glesser ]

Posted by Paul Adsett (Member # 25) on July 21, 2014, 09:04 PM:

Bear in mind Janice that both the French Pathe Baby and the British Pathe Ace were only capable of filling about a 24 ins wide screen, and even then it had to be a glass beaded screen to get decent brightness. The Pathe ads for the Baby, showing what looks like about a 6foot wide screen are very misleading in that regard! These hand cranked projectors will never come close to the brightness of even an entry level 8mm projector, but you can safely go to a 20 watt halogen lamp for non-notched films, just make sure you switch off the lamp when the film is not moving.

Posted by Janice Glesser (Member # 2758) on July 21, 2014, 10:32 PM:

I appreciate your comments Paul, but my expectations never compared the lamp brightness of the Baby to my 8mm projectors. I'm just trying to at least match the original brightness with the conversion bulbs. The bulbs I just tested were projected to a small screen I've set up on my wall at about 3 feet away and in complete darkness. The image is only about 5 inches and barely visible.

I'm pleased I accomplished the conversion to this point.. just not satisfied yet with the quality of light.

Posted by Dominique De Bast (Member # 3798) on July 21, 2014, 11:14 PM:

Paul, I would add to your post that the Pathé Baby is not the ideal projector for not notched films as you can find brighter projectors.

Posted by Janice Glesser (Member # 2758) on July 22, 2014, 12:30 AM:

The Baby is fine with the old bulb...no complaints other than the replacement bulbs are difficult to find and if you do find one...very expensive. Hence the solution for an alternative light source, which both of you have successfully implemented and are satisfied with the results. I'm just attempting to accomplish the same. The majority of the films I have are commercially produced notched films, which the brightness of the old 20W bulb is adequate. Of course even with the old 20W bulb you can't let the film stop in the projector for an extended period of time. This is why I use an on-off switch to quickly turn off the light.

I'm confident that I can reach a satisfactory resolution. It just takes me a little more time (lots of trial and error) since this is not my area of expertise.

Posted by Dominique De Bast (Member # 3798) on July 22, 2014, 09:03 AM:

There was a store in Paris, sadly now closed, that had a stock of new Pathé Baby bulbs, I mean specially made, not an old stock of unused ones. I don't know nor how many they had nor what happened to the bulbs. Maybe someone bought the stock.

Posted by Janice Glesser (Member # 2758) on July 22, 2014, 11:11 AM:

Dominique...I've purchased a couple of Mazda bulbs on Ebay so I still can use these bulbs in the interim until I get the LED working satisfactory. The G4 socket base I'm using will allow me to just revert back to the original wiring and bulb at any time. That's what I like about it. However, as Paul has said many times...the old resistance plate is dangerous on the Baby and for that reason alone the electrical system should be modernized.

I think the LED route is well worth pursuing, but tricky with the Baby. It requires condensing and projecting light through a very small opening. New LED bulb styles are coming out rapidly these days. I'm going to try the round format next. I think this will at least disperse the light more evenly.

Posted by Anna Vacani (Member # 2736) on July 22, 2014, 03:48 PM:

Hi, In the magazine 9,5 Summer 2013 is an article about converting Pathe Baby to LED lamp.

Posted by Anna Vacani (Member # 2736) on July 22, 2014, 03:52 PM:

Hi, In the magazine 9,5 Summer 2013 is an article about converting Pathe Baby to LED lamp. it is clearly describe in the article.

Posted by Janice Glesser (Member # 2758) on July 22, 2014, 04:46 PM:

Thank you Anna for the reference. I'm not familiar with that publication. If you have read the article was it geared to a halogen bulb or LED conversion. Did it recommend a specific bulb brand...voltage...and wattage? I'm really only interested in a LED solution right now.

Posted by Janice Glesser (Member # 2758) on July 22, 2014, 08:09 PM:

Good News! I discovered with the halogen bulb that height positioning is very critical. In raising the bulb ever so slightly the brightness increased to closely equal the original bulb. This is great....not super bright, but very usable [Smile]

Changing the height of the LED bulb didn't seem to effect the projected brightness.

Posted by Paul Adsett (Member # 25) on July 23, 2014, 10:13 AM:

Thats right Janice, you have to adjust the height of the bulb holder in the tube to get the maximum brightness. It makes a huge difference if that bulb filament is not dead on the optical axis. Same thing with rotating the bulb holder in the tube to get max brightness and uniformity of brightness..

Posted by Anna Vacani (Member # 2736) on July 23, 2014, 10:39 AM:

Hi, Janice. The article we have is about LED conversion.The important thing is - you must use about 5 watt, 5 mm single LED. This must line up with the center of your condenser lense. A multiple aray type of LED is not good, because a lot of the light will not go through the condenser lense.
Here you have a link to LED company, in USA, page 5 - looks similar type to this article:
http://datasheet.octopart.com/OP-4LN2-0492-Lamina-Ceramics-datasheet-5311760.pdf
If do you need to contact me, go to our web site:
http://www.binoculars-cinecollectors.com/
Good luck Janice [Smile]

Posted by Janice Glesser (Member # 2758) on July 23, 2014, 02:02 PM:

Paul...I can see now the importance of getting the optimal positioning of the lamp. The difference is night and day. I kind of knew this with the bigger Mazda bulb. I don't know why it didn't occur to me with the halogen, which seems to be even more critical. I'm still going to try a 20W bulb for the non-notched reels.

As far as the LED...Perfecting this solution may take a lot more time and experimentation. What Anna says about a single LED source makes sense.

Posted by Ken Finch (Member # 2768) on July 26, 2014, 09:52 AM:

Hi Janice, I have just been reading the posts about your substitution an L.E.D. for the Halagon, especially the poor results you appear to have had with the latter. Paul is absolutely correct. I had a good look at your photo and the halogen filament is well below the centre of the optical axis. The filament should also be at the same horizontal position as the original lamp to obtain even brightness over the whole of the aperture. You should be getting a much brighter picture. You should certainly be able to obtain a good picture between 2 to 3 feet wide with the 10 watt lamp. As to LEDs, I have decided against these for the time being as they are very expensive at about £20 each and also require extra electronics to supply a stable DC current. You cannot simply connect it to a 12volt output transformer. This is all built in to the base of the ones designed to replace standard types of light bulbs. The 10 watt halogen bulbs are considerably cheaper, run cooler than the original Pathe bulb and tend to last longer. Ken Finch [Smile]

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