Feature lamps on early solid state games will strobe unless one replaces the lamp driver board to accommodate LEDs. I have incandescent bulbs in mine. They do tend to burn out quicker. Steve at PBR admitted the Eiko bulb filaments are not as sturdy as the older GE and Holland bulbs. I tend to use LEDs on my EM games under inserts (also lower heat). Yes, Warm White retro type as others have mentioned. I have enough old original 44/47 type bulbs that I cull out of project games to keep for use above the play field These can be cleaned up in an ultrasonic or some have even suggested Tumblr but I like the ultrasonic treatment.

Every game I have ever switched to hi tap, only effects the coil voltage not a general illumination 6 volt side of the Transformer.