I once have a suntax 928AF, the trigger voltage is safe as I asked directly the suplier pero dili ma adjust ang power so I switch to Canon flashes aron ma isa.
Here is a list of trigger voltage of the flashes you may want to use:
TRIGGER VOLTAGE LIST
wala dinha ang suntax, pero para safe try to email ang support sa suntax na webpage,
Suntax - Contract Manufacturer and Photography about sa trigger voltage...pero the best thing you can do with that flash is to use it as off cam, dili na ma trigger ug PT-04, just use the light sensors.
hope that helps.