http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

https://www.play-asia.com/super-joyb...en-70-qc4.html

That provides enough voltage for dual-shock motors, and is still available.

The extra voltage comes from drawing more amperage and converting it with electronics. That's why your 120 volts coming out of your power outlet can power your computer to power your 5v USB devices, and the voltage your PS2 takes.