But is this really something that needs sorting out? Bigger problems out there in the audio world than something only audible 1" from the tweeter.
No, there is nothing which needs sorting out, as I have mentioned, what I am hearing is just the normal noise floor of the amps: very smooth, extremely low level hiss, most likely just the thermal noise of the input stage. And, this noise is only audible at night, on a calm quiet night, ear directly up to the tweeter. Take into account my home is in a rural area, on 3 acres, with virtually no neighbors, at 9,300'. There is also only one road, with no traffic at night, within a mile of my house. It is much quieter here than anywhere with neighbors, or roads with cars, or other people around talking, or anywhere in a suburban or urban environment.
After much thought, I am going to do this build the Hypex way: no AC ground connection (I float my other components as well in respect to AC ground) with secure, and double insulated internal high voltage AC wiring, pin 1(s) direct to chassis through a very short 20 awg wire, nCore input cable shield direct to chassis at a different point than pin 1, but very close to the XLR jack. I will also remove anodizing/paint from the chassis sections until there is relatively low resistance continuity between the chassis panels, this may provide a little bit of shielding from the outside world, but not really. Considering the ~1 uF of C directly at the input of the SMPS600s (two of them) I will also place a .01uF cap at the IEC for a little bit of added high frequency filtering. If this build results in any "problems", then I may re-visit other possible solutions. I am also considering transformer coupling for the output of my DAC, as this may solve a couple of (very small) problems, and then connecting only the "ground" (actually the shield) of the transformer to pin 1 of the DAC output. When the build is done, I will post a couple of pics in the approriate thread.
