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This is a review and detailed measurements of the Auralic Leo GX "atomic clock" outboard option for the Vega G2 that I just reviewed . It is on kind loan from a member. The LEO GX costs US $8,299.The LEO GX comes in the same enclosure as the Vega DAC:Strangely for a device that just produces a clock pulse for the DAC, the thing goes through a lengthy boot process and "loading applications." Likely it is the same OS as the DAC and is there to manage the display and such.A one hour count-time timer is shown on the display. The clock source is "oven" controlled and they are waiting for it to reach target temp. The unit works immediately though so you don't have to wait for that.The back panel shows more connectors than you would expect:In addition to the coax connector which carries the clock source to the DAC, it also has a required HDMI connector (not to be confused as a real AV HDMI connection). That is there for control as the LEO GX produces the native clock of the DAC based on current sample rate. So it needs to be told that rate. Typically such clocks generate a single frequency that the DAC then divides down to generate the sample clock. Because of that, the LEO GX has two atomic clocks, one at 44.1 kHz and multiples and the other, for 48 kHz and multiples.I started with the all important jitter test since that is our main tool for examination of clock quality and jitter:As noted on the graph, waiting or not made no difference. Nor did the addition of LEO GX clock. Performance remained identical and excellent all around. This is a very high resolution spectrum analysis as you can tell by the tiniest little pulses peaking down at whopping -150 dB. Yet it can't find any difference in the analog output of the DAC -- the thing you listen to -- whatsoever.Here is our dashboard view, first with the LEO GX clock active:I think turned off the Master clock as suggested in the menu to compare the two modes and I was greeted with this:The clock rate was all over the place as were the rest of the numbers. Clearly the DAC had lost its mind, I mean clock source. So much for any ability to compare. It took a reboot with its lengthy period to get functionality back. This is a serious bug as comparing the modes is exactly what you would want to do when you first get this clock.I played through a few of my reference files and I was shocked to hear a bit more detail. There was more air between instruments. The bass was ever so slightly quicker. I don't think I have ever heard a DAC sound this good before!Of course, none of that happened. The DAC sounded just as good as it did yesterday without the external clock. I did not try to time the tracks to see if they finish more on time so maybe they did.I don't doubt that fair amount of engineering and cost has gone into producing the Auralic Vega GX. As seems to be the trend, designers chase lay intuition of audiophiles and produce products to fill that "need." Audiophile thinks a more accurate sound means more focused soundstage, etc. companies deliver. Psychoacoustics tells us that we are not at all sensitive to rate of playback or no one would have ever listened to analog sources like LP and tape. Variations in clock are important but not its absolute accuracy. So unless you want to tell time from your DAC, you have no need for an "atomic clock."So please, please don't waste your money on such things. And certainly not for US $8,300. For the thousands of dollars you paid for your Vega G2 DAC, you better get the best clock in the business and not need an external source. And oh, an external source can never be as good as a clock source right next to the DAC. The cable degrades the signal as it travels over a few feet of that. FYI, this unit came with a fancy, thick and pain in the neck to screw and unscrew coax cable.Needless to say, I can NOT recommend the Auralic Vega G2.------------As always, questions, comments, recommendations, etc. are welcome.I need to buy a more accurate watch to better test these "atomic clocks." So pleasewhat you can using