I have two standard Sqeezebox units (SB3's as I recall) we could use for the test. I would have to have BRM bring the "upgraded" power supply or purchase one for the test. (We could even run a control test swapping only the SB units to eliminate any possible variation related to differences in the SB units themselves.)
Changing power supplies on a single SB will not provide an immediate A/B comparison and the time delay would introduce far more variability than RF (in my opinion). Switching at the DAC would provide almost instantaneous comparisons.
When we made the final SoundScape driver selections, having Dennis Murphy's magic comparo box made a huge difference. When switching speaker cables (before using the comparo box), everyone THOUGHT they had an idea of which drivers were better. But with the remote-controlled A/B switch, the differences in sound quality were immediately evident and unequivocal. In that case, the elimination of switching time showed how dramatic the differences were (greater than I would have thought listening to both individually)and made the analysis easy.
As for RF, perhaps we can run them so that each SB unit is 3ft on either side of the DAC and their respective power supplies are as far to the right and left of the SB's as possible. This should put the power supplies almost 6 feet from any other components and the closest the power supply cables would be to any other system cable where they connect to the SB units themselves. Did that make sense?
As for location, we can do it in my listening room. I have a pair of SoundScape 10's hooked up right now and they should surely be able to resolve any possible sound quality difference.
While amps, speakers wires, etc, could also be tested at the same session, it would be more difficult as the tests would not be totally blind and there would be time delays between each component being tested.
- Jim