I just rewired an old MRC HO powerpack into a transistorized throttle. The new low speed control of my locos is very smooth, but I can't avoid that little jackrabbit jump since the output is very pure DC.
I tried a little experiment. Don't ask me how I thought of it but this actually worked. I wired a small PC power supply fan in series with the pack output. I couldn't believe my eyes. The little fan started to spin first, then my loco began to crawl at that one tie a minute pace I'm so used to in my other packs. The loco didn't get up to a very high speed at full throttle because the fan was using 8 volts leaving only 5 volts for the loco tops. So this method could never bee used for full range.
Can any of the electronic wizards on the group explain how a little PC fan was able to pulse a loco? The fan amp rating was .15 amps.