What did a good 10 MHz clock do for your Gustard R26?

Don’t put lipstick on a pig. Send this DAC back and move on. 

Yep I’m talking about R26. If you have a second unit that doesn’t sound right then you should be done. 
 

there’s a lot of hype going on around the LAiV Harmony DAC. May be try that? Seems to be receiving lots of praise from the reviewers. 

@magon so by now you’ve tried 3 dacs. Gustard R26, your modified Gustard and the PS Audio DSD MkI. Just to summarize…R26 is dark and dull, the PS Audio is too bright, snd the modified Gustard is just right?

This begs the question - have you tuned your headphone and speaker system (s) to the sound of modified Gustard so much that the other two DACs don’t sound right? Both R26 units sounded broken. And I’m most surprised about your assessment of PS Audio DSD. That DAC is anything but bright. So my suggestion based on this DAC shootout you have conducted, is to take a close look at your system, room and the associated equipment as I suspect you have created a synergy for that particular modified DAC and now nothing else can integrate. Is it possible?

@magon interesting. So…couple of things…

I’m also using Aurender, but N200, to feed my PS Audio DSD MkI. I have never experienced any brightness with it. The bass is prodigious. The vocals are velvety smooth. So there’s something there in the associated equipment in your system that doesn’t match. Could be impedance mismatch between B&K amp and PS Audio DSD (not sure if you use preamp). 
As to modified gear - I’ve had bad experience with a modified amp. I loved it in its stock form but it was horrible after mods. It caused tremendous fatigue and I couldn’t listen to my system. That was it for me as far as mods are concerned. Keep in mind that a manufacturer will voice their product to be as neutral as possible. Changing parts, even for better quality ones, doesn’t always result in better sound. In addition, selling a modified component becomes more difficult as the sound signature was altered and the potential buyers understand it. It becomes unpredictable and no one can anticipate what it will sound like. Same applies to cables - the DIYers of the world don’t have the means and the equipment to come up with a cable that would work with wide range of components - they usually tune it to their personal preference using the components available to them at the time. 
I wish you luck in your quest for a better dac and have that tinnitus checked out for sure. 

@magon actually not a bad idea! I always go back to stock cables to set a baseline for a component’s sound when evaluating it. Aurender includes a very nice usb cable if you still have it, worth a try. Or just use any basic usb and power cord. 
Awaiting your updates. 

Interesting. Take few days to get used to the sound and run it 24/7 to let the cable settle. The PS Audio DAC won’t scream look at me I’m here and attract attention to itself. But it plays music in a very satisfying way. Nothing stands out. 
It takes a bit of time to get used to it if you’re coming from a more analytical dac. 

Awesome! Wait till you try a good power cable on this dac. 

Cool. You have to go with whatever suits your preference and perception of best sound. It took me a while to begin appreciating the PS Audio DAC after the somewhat more forward and resolving but cooler sounding Bricasti M3 and now I just love the DSD DAC sound. It’s all about synergy and personal taste.