[Cjtamu]

If anyone mentioned it I missed it but Parma controllers are no longer made. You can find them on Evilbay etc. If you're not trying to stay old skool DS makes resistor controllers. Bought a pair a couple of weeks ago and have been happy with them. Teh ones we bought have a switch that allows you to adjust resistance.

 

[Cjtamu]

HOW they work is beyond my cavemanesque understanding of electronics. I'm essentially the Cole Trickle of slot cars! It's just a 3-position toggle switch, and you can definitely feel the difference in response. I assume it's hooked to a potentiometer of some type. I know Rich has talked about building one with variable resistance but I don't think he liked it much. I got these from NJ Nostalgia Hobby. He has a 120 ohm controller that DS makes just for them, but don't know if DS does these for him in house or if he modifies himself. Two versions, one that's 35/45/55 ohm and one that's 60/90/120. Have so far been able to get a feel I liked with all of the cars.

 

[Cjtamu]

I believe they have additional resistors wired in parallel. Much like a 2 lane highway that widens into four, as they are added, your net resistance drops. Sort of.

When it's time for cleaning and I pull the cover off I'll shoot a pic.