I use the Halogen replacement bulbs in my 28 Essex> Am very pleased with increased light output for same wattage. I was able to buy direct drop in replacements for standard bulbs.. I can't help you where to find them in USA but Jon Battle has previously purchased them in the US. You can find Jon in the "Club members list.

David, are you saying that you put Halogen bulbs strait in to the Original Essex sockets?? realy? 12v or 6v?

I found what I was looking for here. Nice folks:
www.ynzyesterdaysparts.com

That's exactly what I'm saying!! I'm still on 6 volt

For new quartz-halogen 6-volt bulbs that should fit the original socket: Little British Car Company http://www.lbcarco.com/ is the USA Distributor for Classic & Vintage Bulbs, in Australia: http://www.classicandvintagebulbs.com/page2.html . (The owner of Classic & Vintage sells his bulbs at the Hershey fall car show, so you might pick them up there too.)

For the original type tungsten filament bulbs: try Gregg Maroney, http://www.hudsonterraplane.com/ForSale/lightbulbs.html

Only possible question with using the quartz halogens in the 20's and early 30's cars, is whether your generator's output is sufficient to power them.

Jon, The quartz halogen bulbs use the amount of power that the watts of the bulbs say.The q h bulbs that I got are the same watts are the original bulbs I had & so use NO MORE power but they are much more efficient & put out much more light for the same power consumption. In other words, if your generator output was sufficient for the original style bulbs the it will also be sufficient for q h bulbs of the same watts!!

Sorry to be quite so wordy!! 😆

If you wish to use the original bulb, I have some ,nos, but personally
I would buy the modern brighter replacements. 21 cp even with bright reflectors are not very bright.

"Ric"