Project Speed box is the right idea but only puts out about 5 watts and you'll need 40 watts. If you have Project speed box or the music hall equivalent, it's simple to make an amp to step up the power of the speed box. As far as I know the speed box does control the frequency sent to the table. It's a simple matter to verify.I don't think the Project Speed Box S would work for you, sorry.....for reasons that others have mentioned, speed appears not to be controlled via AC power. You can see what I was talking about here:
https://www.musicdirect.com/analog-accessories/pro-ject-speed-box-s
No longer available, but you can find one on the big auction site. Again, I don't think this is what you are looking for. There are others as well, my Wave Mechanic being one such, but nothing that appears suited to your situation.
