Interesting Observations: Stellar, Ultrarendu, FMC's, Dectet, and wireless spectrum

I’ve had the pleasure of having a SGCD and S300 setup for a few months now and have been very satisfied so far with this setup compared to my previous Denon AVR.

Recently I’ve moved from direct USB connection from my Mac with an IsoRegen to the UltraRendu Ethernet to USB source. One major discovery I made a few weeks ago was the very significant SQ bump by having A+ perform PCM ->DSD128 conversion.

Now for some interesting observations.

(1) Upon initial hookup of the UltraRendu I noticed amazing sound but a very forward high end that was hard to listen to for more than a few minutes. Whats going on here? Ethernet is supposed to block noise. Well… it appears ethernet doesn’t block ground loops from occuring. I am using a Belden 6a with a floated shield. Upon installing a isolation transformer to the coax line going to my modem router… the noise went completely away.

(2) Even with the isolation transformer, I observed significantly better SQ from incorporating a pair of FMC’s. For those that are new to these, these are ethernet/optical converters which are used to decouple any upstream electrical noise (at least in the audio world that is). In this case I had moved my modem/router to my common line power strip as well as the sending FMC. On the receiving side FMC, this was plugged into the dectet. Having it setup this way… even without the isolation transformer there is no electrical connection to the modem/router or sending FMC. Now SQ will be dominated by the quality of internal components of the receiving FMC and the power supply used to power it.

(3) Switching out the stock SMPS for an iFi 9V gave a minor SQ upgrade… nothing extraordinary. But… when adding a Jameco 5V linear power supply the sound immediately became smoother, more realistic, and had less high-end emphasis.

(4) On a whim I moved my SGCD and S300 off of the Dectet and straight onto the wall… there is a PS Audio Powerport on a 20A dedicated line. More dynamics… more life! YES!

(5) I played around with turning off the unused wifi channel to reduce RF pollution near my audio gear. You see my modem/router is a few feet away from all of my equipment. My observation was that running only the 2.4G spectrum gave a congested but slightly thicker sound signature. 5G though was clearer… more detail and still musical.

(6) The curve ball… I received a new pair of FMC’s mod’d by SotM where they changed replaced an internal switching regulator for a linear regulator and upgraded the capacitors. Well, expectation bias would tell us I should be writing about how this is audio nirvana. Nope! Something was wrong here. As I started to crank the system… where is the bass? Why is it harsh? Why don’t I want to crank it ?How could a new linear regulator and better capacitors sound worse? Well I was facing up the fact that I might just have to use the old FMC’s and suck it up I paid for modifications that are worthless to me.

(7) I turned off the 5G spectrum and moved to the 2.4G. Ok… some harshness went away and it became a bit more musical. I was pretty happy. This was interesting how changing some components in a ethernet device changed my perception of RF interference of my modem/router.

(8) Next I moved back to the Dectet… S300 back to HC section, and SGCD into its own isozone by itself. Wow! Right on the money! Back and forward with the wall and the Dectet, how the crap am I getting more dynamics here! This is so smooth and musical, amazing! Switch back and forth the receiving FMC and still there are pretty big differences here. The stock one with noisy switching regulator inside has sibilance, doesn’t pull me in, voices aren’t right, cymbals are too forward and jumping out in front of other instruments. Upgraded FMC is so smooth, cymbals are a little laid back but they are imaging very nicely and just sound more musical. Everything is more musical.

There you have it… an account where changing out some internals of an upstream ethernet device both changing my preference for wireless spectrum AND changing my mind on Wall vs. Dectet. To me this has to do with balancing noise profiles in the Audio chain. By potentially removing/modifying the noise spectrum in the upstream ethernet device, it significantly altered my perception of SQ differences for where my audio equipment was plugged in.

Fun times clapping_gif