Lowering the noise floor

One of my favorite quotes was by Shannon Dickson in Stereophile magazine, referring to CES in Law Vegas that year, “I went to the geek meet in the Desert, where once again almost all of the exhibitors failed to get up out of the noise floor.”

Power power supplies, power supplies, power supplies.....oh my what a difference maker they are when it comes to noise. Wether computer audio, amplifiers, ac from our homes etc ... they are the place to look for obtaining the best possible sound. Noise is indeed the biggest hurdle on the road to natural and beautiful sounding music.  I am talking about noise introduced into the signal path. Not background noise or hiss.  Power supplies are often the bottleneck to great natural sound and they are indeed in the “signal path”. 

     The largest reduction in the noise floor I've  ever perceived in my many systems over the past 40+ years occurred about 3 years ago when I first substituted a class D amp in my system after using class A/B amps for virtually my entire home audio life. 
      In retrospect, there have been many changes in my sources (vinyl to cds to Super Beta Audio recordings of my cds to DVD-A and SACD to my current computer audio with ripped cds and 24 bit/96khz downloaded files) and many changes in my speakers (no-name Pacific Stereo to Klipsch Heresy to Mirage to Maggie IIB with single sub to my current Maggie 2.7qr with 4 subs) but relatively few changes in amps (from Pioneer and Yamaha am/fm receivers to Adcom separates to various mid-level class A/B amps with a VTL tube preamp to class D stereo amps to my current D-Sonic class D mono-blocks).
      Without any doubt, the change from class A/B amps to class D amps in my system resulted in the biggest perceived lowering of my system's noise floor of any system changes I've ever made.  I was not expecting this dramatic perceived noise floor lowering with the switch from class A/B to D amps since I didn't recall it being mentioned by others who had switched to class D amps. 
       I did immediately notice other changes to the sound of class D that others had mentioned such as increased bass response, increased dynamics and a detailed but smooth mid-range and treble response comparable to good class A/B amps.  But the lowered noise floor, that made it seem like the music was emerging from a dead calm inky blackness, was just a big bonus that made all my familiar music sound even better.  I also think this lowered noise floor enabled my system to sound more detailed. 
     Given these results with a class D stereo amp,  I subsequently bought another stereo and a pair of mono-block class D amps to replace the remaining class A/B amps in my combo ht and 2-ch music system which has increased the performance of both. 

For what it's worth,
     Tim 

I have come to the conclusion that success in home audio reproduction is largely about speakers & room treatments.

Lowering the noise floor (EMF noise) can be very useful for digital audio - the most critical issue is to ensure galvanic isolation.

An isolation transformer for the whole thing is usually a good idea.  Dedicated lines are costly unless you are doing new construction anyway.

Power supply indeed. But also power cords and cables. I think of a power cord as an extension of the power supply. As for the cables, especially interconnect cables, it is quite obvious too. XLR cables have no inherent advantage with short lengths.