Actually if I'm being a little bit pedantic Yikes is actually the first gen G4 (though it is essentially just a re cased B/W G3 with a G4 CPU card)The G4 was introduced in mid 1999, ADC was added to G4s in mid 2000.
Sawtooth, that this thread is about, is first gen G4.
But either way the Sawtooth doesn't have ADC support so no +28V rail is needed. I'm pretty sure the DA dose have ADC support which is where some people get confused as it looks almost identical to the sawtooth