@David
Ok - I can only comment for the r26 mostly not the a26 but hopefully this helps:
- the r26/a26 already has a good clock and an excellent clock synthesiser. All reports on the r26 are positive Sq wise, including those where they have opened up the box and inspected the hardware which should be enough to prove that it's a good dac as it is out of the box. Initial reports on A26 are similar.
- There are different conflicting messages on external 10mhz clocks. Goldensound, as one example, has some good reading on this, and doesn't think the trend towards external 10mhz clocks is great, but does think that master clocks can be beneficial. His measurements with the gear he tested saw some increased levels of noise / jitter with certain clocks. So there may be a tradeoff of increased accuracy for some increased jitter. If noise / jitter on your system is already excellently managed, maybe this is not a big deal, but there is still a trade-off. Others disagree on this topic. So the information set is a bit muddy.
- Others, including myself, have added the clock and claim there are benefits. For me, my benefits were small, and if I were listing out the tweaks I have done on my R26, this update would be towards the bottom of the list - adding just a few percent to soundstage and clarity / smoothness. The FMC tweak, as just one example, is a much bigger bang for buck tweak (which may be down to my house and my specific network). i have actually pulled out all my tweaks, and tested them 1 to 1 and cumulatively so am confident on that statement (for my system - not for others). That said, the caveat to my assessment is that I am testing with a modest system which you can see in my sig. Maybe the benefits of a clock are limited in my system. However, in either case, I am delighted and astounded frankly by what this system, as a whole, is producing, and am happy with the clock purchase. However, it's bang for buck performance is not as good as other things i have done.
- If you check out the L26 audiolab measurements for the R26, you'll see that FFT measurements have some side lobes which should be inaudible but can be cleaned up by a better clock. There is also some skeptisicm (as there generally is on this site) by that author that maybe the FFT performance is deliberate in order to sell the clock gustard also sells. Now the author offers no evidence for that. we don't know whether Gustards FFT performance here was a cost limitation, a design limitation, or something else. But this website clearly states that 'measurement wise ' (noting that this may or may not translate into audible results) - a better clock could be added to the r26
- If i was doing this again, i would skip the LHY Ock 1 clock, and i would go straight to the Lhy SW10 - getting a better clock and a FMC / Switch all in one, out of my router before the gustard, i think would be a better bang for buck investment than going for the cheaper LHY ock 1 clock. i think this would be a top notch tweak but I am only appraising this by the specs - i have not purchased it and it is a v expensive tweak but combines 2-3 pieces of functionality into one good unit.
- In either case - know that you are getting a fantastic dac (in the R26 case anyway - i cannot directly attest yet for the a26) for the pricepoint. The clock in my view is an optional add on, with gains to be had, but more like adding your favourite topping to your favourite ice cream. If you want to improve the potential of your dac, i personal think there are other things to focus on first (if you haven't already done so) such as good isolation on your speakers and equipment, room acoustics / treatments / room correction, great networking or ddcs depending on your dac input choice, good power management and cabling, and then clocks.
Others will have different views to mine, which is great, and i think goes to show that the benefit of different tweaks / add ons are v much system dependant.
