Well, this whole conversation is irrelevant now. After reading many posts about how the noise of the 383L was reduced with a higher voltage input (13.
, I decided to test my noise levels using 12v versus 13.8v inputs.
What I found is that the 12v actually had slightly less noise than 13.8v! This seems to be opposite from what others have experienced.
12 volt AC input:
Read noise = 9.84e-
Total system noise = 11.03e-
13.8v DC input:
Read noise = 10.55e-
Total system noise = 11.82e-
So, I can happily keep using my current 12v AC power supply and know that the noise level is not adversely affected by 12v vs. 13.8v.