My understanding is the MTH Z500, Z750 and Z1000, are chopped sine wave, while the Z4000, is pure sine. I have a Z1000 and a Z750, and all my engines are Protosounds1 (QSI). They all run just fine on my existing transformers.
If I buy an MTH engine with Proto 2 or 3, am I going to need a different transformer, i.e., pure sine wave?