What I am about to post here is not intended to say that anything that several you have posted in the last 5 or 6 post is wrong.
About a year ago I got a fidata NAS that has only two outputs. One is a dedicated and pretty well isolated Ethernet output that is meant to carry the selected stored audio file to a network Player ( a DAC with and Ethernet input ). The other output is a two way USB port that is meant to connect to DACs that do not have an Ethernet output. Care was taken to make the USB port capable of high SQ. ( All of the cables that I mention here are 0.5 m TOTL WireWorld digital cables. ) Since the Mk2 does not have an Ethernet port, I used the USB port to listen to music from the NAS. It sounded very good.
When the AirLens became available I got it and have used sijmply as a DDC and an isolation device. I connected the fidata NAS to the AL via a Ethernet cable and then connected the AL to the Mk2 via an HDMI I2S cable. The music sounds slightly better this way than through the USB connection. This tells me that the USB connection to the Mk2 is really good.
When I first got the MK2, I was using a NAS to streamer to Matrix 2 and Dragon HDMI cable into itās I2S input, and when I compared it to NAS to streamer to a Vahalla2 USB cable to MK2, I didnāt hear much of a difference, which means the 2 inputs are pretty much an equal. But when I connected a better ChordMusic USB cable to the USB input, the sound was noticably better than the I2S input, so it really is up the quality of the cable you use for connection that determines which input is better.
If you go the USB Route. You can benefit sound further using HDMI shorting plugs on both i2S1 and i2s2. These can be made by connecting pins1 through 12 in a male HDMI plug.
The MK2 is supposed to be able to deactivate these circuits and USB slso. I have found the shorting plugs work better than the sofiin wuieing the unused inputs.
The shorting pins may be a benefit if those inputs are not terminated by a source but I do not believe that there would be any benefit of someone who have those ports used plugging and unplugging sources and shorting pins.
Digital cables make a stark difference from my own experience also. There are many more high-quality USB cables than HDMI cables out there so I tended to think using a great USB cable for MK2 will bring out the best of it.
I am using I2S 2 and USB input from MK2, and when I first inserted the shorting plug at I2S 1 I was surprised to hear an obvious improvement too. It never left MK2 since. I wonder if the final Massive update will eliminate the need for a shorting plug.
Well the beta version of massive supposedly enabled the shut off of unused inputs. My gut feeling theyāre constantly querying to see if a new source is plugged in so they arenāt truly deactivated. This is something only Ted could tell us. But when shorted it sure gets quieter. I didnāt notice until I knocked a shorting plug out accidentally and had to go hunting on what changed to my previous black background. I need to modify my shorting plugs since they are interfering with the button head screws for the i2s connector and donāt fully engage like the tubulus HDMI cord. I will have to get out the dremel and hog out a relief for the fasteners heads so the shorting plugs fully seat. I hope PS audio improved design so feed through connectors fasten in back panel with countersink screws on the non beta units.
Remember that before he left the forum, JK Richards noted that some of the MkIIās heād seen did not have the metal āfingersā aligned properly inside the chassis so that the shorting function would even work. I seem to recall in one case he found at least one that was broken. If you all have already checked inside on this then you already know.
Thatās a good point. I have my shorting plugs wrapped in copper foil and they touch the button head screws thus then short out the i2s circuit to ground. That might be why the software functions donāt seem to work. But JK fixed Donaldās unit and he still hears an improvement with one shorting plug.
Tony,
The Metal fingers you are speaking of are only for EMI reduction to meet European standards and are not involved in any of the grounding options. I made the same mistake and I believe James corrected that misinformation. the shorting pins are only using actual contacts of the HDMI connection.
The Automatic option does turn off the unused inputs. There is no polling to detect a signal as when you change the input the circuit brings the selected input active and disables the unused one. You can easily prove this function by booting up a usb connected computer without having usb selected on the DAC. You will find the computer does not see the driver for the DAC.
I will remove the shorting plug later, and listen to for a day to see if I am having a brain fart.
Wait, Iām supposed to try a different mixing of Puritan and P15 today too. Well, I have three days left before I shut down the system for a couple of weeks (Japanš±).
Well, I still like JKās shorting plug inserted even though I had i2s 1 set to auto shutdown. I cannot pinpoint the improvement, but when it was removed within a few minutes the music no longer had the same smoothness. I almost needed a drink this early in the afternoon. Then I plugged the HDMI shorting plug back, and I saved a drink.