For Gustard R26...which bang for the buck: DDC or LHY OCK clock?

The hdmi (i2s) cable would be 1.5 or 2 metres in length.

You should read my post above.  HDMI i2S cables need to be as short as possible, and 1-1.5m is very suboptimal.  Most people familiar with the connection recommend 1 foot or less.  Or, you can shoot yourself in the foot and use a longer cable.  I tried. 

@soix Thanks for the recommendation of trying the shorter I2S/HDMI cable length - there was a subtle difference in favour of the shorter 1ft length vs the 2ft incumbent, though I guess if there’s such a thing as burn in for HDMI cables it might improve further. Incidentally the logic of shorter is better for I2S makes intuitive sense to me and may also help explain why the internal streamer of the R26 (and other high quality DAC/streamers) can sound very good indeed - the internal i2S connection will be extremely short - just the distance between the streamer and main DAC circuitboards essentially.

@peareye The HT DC III is an excellent cable - clearly the best one I’ve tried. HT >> LMR400 /> C2 >> Minicircuits 50ohm >> Pro audio 50 ohm > Hifi coax digital 75ohm.

Best performance/ price ratio is the LMR400 - which after a week’s burn in - and it really does take that long to sound good - it surpassed the C2 in terms of resolving power and dynamics, though the C2 was warmer and smoother so more forgiving. Downside of the LMR400 is it is really thick and rigid plastic tubing like a plastic hose so is cumbersome to use and can feel like it is putting a fair bit of lateral stress on BNC sockets.

@pinwa John Swenson certainly knows his stuff (it’s an interesting paper isn’t it) so all the best with that - should be a cost effective route to achieving a good standard for sine wave. Incidentally I’m a sine wave fan - worked best for me with the OCK 1 & 2 with the R26 with all the cables I’ve tried so far.

@kereru Yeah, my comparison of sine wave vs square wave from the OCK-2 to R26 definitely favored the sine wave.  I still think it is crazy that a timing signal can so dramatically impact the sound and is so sensitive to cables etc..  And I am on day 3 with the OCK-2 and there is no question that it has dramatically improved the sound of my system.  I spent most of this evening comparing my Rega P6 with the AT-ART9XI cartridge and Hegel V10 phono pre to the R26/OCK-2 and for most of the records I listened to I couldn't express a preference for the vinyl.  That wasn't true before the OCK-2.

Where did you buy the HT DC III?  I can't seem to find a source for that.

It's remarkable how much difference a very good clock makes isn't it. Well you'll be pleasantly surprised by the further benefits that are possible with better cables (or cable / filter combos). 

Source of the HT DC III: Audio Accessory HK - a trading/website name of Labkable an official distributor of HT cables:

https://www.audioaccessoryhk.com/pr...y-dc-iii50-ohm-single-crystal-copper-成品線-bnc/

You need to use Google webpage translate.

You order and pay for it then they email you afterwards to bill you separately for international shipping, total cost works out around USD150, so not cheap but a little cheaper than the C2 but with performance on another level. Its resolution and refinement is superb.

You may be able to source it in the States too but likely more expensive.

I see a dealer near me here in Ontario. I will phone tomorrow

and see what his prices are.