Other Miners like the S5, S7 & Avalon6 supply the ASIC chips connected in a string (Like Christmas Tree lights) The Core Voltage is then determined by the Supply Voltage divided by the Number of Chips in the string. So now dependant on the exact supply voltage you will get a different core voltage.
That supply voltage although nominally 12V is dependant on several factors. First is the voltage it is set to with no load. Next as you load the Power Supply that voltage will often change dependant on how good the PSU is and it's ability to regulate the voltage. Third and often forgotten the wires and connectors connecting the PSU to the miner have resistance and the higher the resistance the more the voltage will drop with load.
So the bottom line is. If you play with Miners buy a Multimeter. Then you can check the voltage that is actually at the PCIe connectors. I think that many Miner problems are PSU / Voltage related, and when presented with HW errors and other unexplained problems it's one of the first things to check.
Rich
If you mine with the 3 above or a s-5+ keep that in mind.
BTW of all these units only the avalon 6 tells you the input voltage so it is the only one that you do not need a meter to know.