Outboard speed control for Thorens TD-124

"The VPI might work, as long as it sends out AC, correct?"

Yes. If you don't already have any A/C products, you can use a regenerator like a PS Audio 500. 2 upgrades are better than 1.

You are referring to the Roadrunner from Phoenix. It can be paired with the Falcon, which controls the speed. But the Falcon can also be used as a standalone. I use it that way, and confirm speed with my trusty Kab strobe.

So, I did some more research on various forums and got some good information.

First, the Nott wave mechanic or VPI SDS will not work because they are for 7 watts and the 124 needs 15. Second, some people have indicated the stepping down the voltage to around 117 volts is advisable because the 124 was made for that voltage not the 123-5 that we know are given. Also, that to regulate the voltage is a good idea because of the voltage swings through the wall (that is really not the case for me as it only drifts 1 or 2 volts at the most). Last, and most understandable is trying to get the best possible sine wave you can feeding the motor as it is asynchronous.

Does these points sound reasonable?

You don't need an external speed controller for the TD-124. IMO the best upgrade you can make to your Thorens deck is to replace the old analog controller board and neon strobe with a quartz controller and LED strobe from Keystrobe UK. The parts are very reasonably priced and the installation is very easy - no soldering required. It's invisible (once installed) and will work with virtually any plinth design.

Try hanze hifi in nederland they have a power supply and a modidication for the engine.