Use the AMB. 
Itās incredibly nice to be able to adjust the RPM digitally during a cut to figure out the best value.
Also having less RPM for shallow engraving jobs, 1- or 2-flutes etc pre-selected in Estlcam is such a nice to have feature. No more thinking.
And being able to run slower in general.
Damn stop making me want to blow past my budget for an AMB spindle!
Fun fact: I used to live where these are made!
c/mon man, youāre an EE. Canāt you just run one hot and go to ground? I mean residential here in the US has 2 legs of 120 and most things run off one leg or the other and some things use both to get 240. I know you could do it if you wanted.
Next youāll want him to will into existence a 60Hz system to go along with his non-existent centre-tap! 
Canāt he just modify tau or phi or one of those? Besides, 50 rounds up to 60ā¦ Lower duty cycle means longer lasting. (Totally not serious)
Put a voltage clamp on your 230 supply and crank it down to just over 50% and youāll get 120. Easy peasy.
Funnily enough, a 230V to 115V autotransformer is basically not far off that. Iāve already got a couple of those floating around for annoying test equipment that I havenāt been able to avoid previously but nothing remotely big enough to run a router. They get pretty big at anything more than a few hundred VAā¦
50Hz to 60Hz shouldnāt make much of a difference.
Iām kinda half tempted to just give it a shot, actuallyā¦ Iām not sure the windings or input filter components would be stoked with it as a general situation, thoughā¦
Need to get you one of those doubles headed low riders, then put two of these in seriesā¦ 
I bought 2 of the carbide er11 routers for 60 usd each with free shipping (now they are marked up) but they lack the software speed control. The t1 price if ok in my opinion.
I have run hard these carbide routers. They have exceed the 500hs each. Runout isnt bad.
There you go! Why by one when you can get 2 for twice the price. A lowrider IDEX where you have to run both routers at the same time because they are 120V each!! Just run them in series.
It makes sense that a convertor for a 10 amp device would need to be largish.
Found this add on for the makita to replace the speed dial with a microcontroller.
GBRL_SPD
Has anyone experience with it?
Quite reasonably priced tooā¦
Shame it doesnāt ship to my location either.
Not yet, but I just ordered it! Thanks for the tip.
I wrote that before actually adding it to cart. It looks like it doesnāt ship to the US. Iāll have to poke around a bit more. Iām really interested in modifying my router this way.
Found something similar in another Forum.
I have no cloue about electronics, but maybe this community can start something based on that
https://community.inventables.com/t/makita-rt0701c-g-code-control-of-spindle-speed-project/21408
haha this is exactly the sort of project I shouldnāt start until I finish 10 other things but thereās a decent chance Iāll give it a go in the future.
I dumped my thoughts in a new topic here if you want to talk more about it.
But it creates a ton of heat doesnāt it? Or is there a better way of doing it?
Yeah, probably. With a slightly more expensive speed control circuit it should be relatively similar, though.
OK, Iām late to the party, butā¦ wow. Impressive feature list for $149, AND it fits into LR4 core like it was DESIGNED for it!
Iām impressed by the claim of closed-loop speed control, in addition to the other nice features.
I would suspect that any router out there with speed control will technically be closed loop. Without that, the speed will vary dramatically with load, especially at the lower RPM ranges.