Quote Originally Posted by John Koehrer View Post
Recollections are kinda foggy but it seems that by putting two or three flash units through one PC contact that the voltages are added together, not parallel.
They won't add together but as the trigger voltage is derived from the HV capacitor via a high resistance, the voltage of the combined connection will be around that of the highest voltage flash.

However, some flashes (my 285s included) measure 5.6 volts which I think shows that there is a 5.6 volt zener diode limiting the voltage. In that case, it might pull the voltages of all the other flashes down to this level too.