Outlets and Wire Gauge? - Please help!

PS - When measuring voltage drop make sure you include the hot and neutral both. Meaning, for a 50’ 12 gauge Romex we expect ~ 3.2V drop per current carrying conductor, of which there are two: Hot and Neutral.

So the total effect of the voltage drop would be 6.4V total dropped (available) at the appliance, a little over 5%.

Assuming linear amps with unregulated supplies:

The lower the AC voltage the longer the recovery time for the amplifier storage capacitors, After an amp has been turned on and warmed up caps will only charge at the peak of the AC waveform so this becomes a bit of self-maintaining situation.

Whether or not it will affect your listening is another subject altogether, but personally I run all my gear after a Furman voltage regulator which keeps the incoming AC within 5 V at any point in time.  After my amp has turned on the biggest issues to my AC voltage are my heat pumps, oven and normal hourly variations in power supplied from the transformer.  My modest 100WPC integrated just doesn't stress the circuit very much.

Most other audio devices are fully regulated, and, with enough excess storage capacity, may never feel any difference between 100V and 130V.

@perazzi28  there is a trip curve for breakers, you would be surprised at just how much current for short durations that will not make them trip.

The install was just completed and I am now afraid to connect my gear. Both my PS Audio PowerPlant 20 and Puritan Labs PM156 both say it is okay to connect to a 20A outlet, but the labels on the back of each read 12A Max and 15A, respectively. I have direct communication with each saying it is okay to do so. I have a Puritan Ultimate 20A PC, but it has a end specific to the 156. I guess I could connect the 156 to the wall and then connect the PP20, but I didn't want multiple hops. I was a bit out of my depth for the two dedicated runs and now it seems I'm out of my depth when it come to what's between the outlet and my gear...

A significant and possibly not discussed/presented in this discussion thread is the relative amount of AC power draw from the AC mains line of the power amplifiers in use.  As we all realize, the amplifiers each of us use are not created equal in this regard. In "erik_squires" latest post stated " My modest 100WPC integrated just doesn't stress the circuit very much."

This is so true; I am fortunate to be operating a pair of mono blocks that their AC power draw from the AC mains line is relatively small.  

I would encourage "izjjzi" to investigate his amplifier(s) power draw with his loud speakers.  

The install was just completed and I am now afraid to connect my gear. Both my PS Audio PowerPlant 20 and Puritan Labs PM156 both say it is okay to connect to a 20A outlet, but the labels on the back of each read 12A Max and 15A, respectively. I have direct communication with each saying it is okay to do so.

Yes, it is. It's quite common, especially in the kitchen where 20 A circuits are run to multiple 15A outlets.  Of course, requires 12 gauge wire + 20A breaker, but this is absolutely routine.

The use of 20A circuits is recommended for multiple outlets, and sometimes required.  For instance, if your refrigerator is run on a circuit with other outlets that circuit should be 20A.