Converting a string of traditional tungsten Christmas lights to LED.

I've decided that adding an electrolytic capacitor where it's shown is not ideal, since in the event of it failing short circuit it would result in the two mains incoming resistors getting overloaded. The circuit is fine without it anyway. I've not actually had an electrolytic fail like this, but I prefer a pessimistic approach to avoid any risks.
It's quite fun to convert a string of old style tungsten push in Christmas lights (fairy lights) to LED, since it means you can swap LEDs and have any range of colours you like. I would only recommend doing this if you have good electrical skills for safety reasons, since it does involve mains voltage.
It basically involves adding an inline rectifier and current limiter to provide a current controlled DC supply for the LEDs. Then you replace all the tungsten lamps with LEDs using the original push-in holders and making sure that all the LEDs are in the correct polarity along the string. You can effectively make up any colour sequence along the string that you want or just use a mish-mash of random LED colours from your stock. In the string shown at the end of the video I've got about 20 colours randomly mixed throughout the string.
The simplicity of the resistive limiter means that it is only really suited for very low current use, but even at a few milliamps, the string of LEDs is actually very bright. Best of all, the whole string now uses about the same power as just one of the original lamps did. The module is potted in standard two part resin for insulation purposes.