parralell port voltage.

[JAZZCNC]

correct me if im wrong surly its like audio speakers etc.. why drive something to its max?
so ie: 500w speakers would be comfortable at 200w.

so 50v drivers will be ok at 45v-48v.. i have read that 542 drivers are 50v max but:::: cappable of handleing 100v.. ill find the post,,,

No it doesn't quite work like that with steppers but it's far too late for me to get into it too much now.
Steppers get there speed/torque from voltage/amps. So if your drives or PSU limit you below the motors ideal operating voltage/amps then you'll get far less speed/torque before the motors ideal corner speed is reached and torque drops away and stalls the motor.
So say at with 48V they will only reach approx 650-700rpm when motor stalls.
With 65v this changes to approx 1000-1100rpm. These figures are lose figures but you get the drift it could be 25-30% less performance than what the motors are capable of giving with correct size drives/psu.

Look around and some where on here Irving did a spread sheet that shows you the differences at different voltages.

All I'll say is your a braver man than me "Gunga Din" if you try to run these drives any were near them voltages. Give them 65V put the kettle on and see how long they last.? Bet you £10 the drives boil before the Kettle.!!