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

@audphile1 Whoa... went to an iFi USB cable (maybe $150 when I bought it 7 years ago) and the brightness in the PS Audio is gone! The strangeness in the bass is gone. It's still a bit bass-light compared to the two Gustards I've had in my possession, but it's much closer to something balanced. It's also less exciting, less microdynamic, less resolution.... but it suggests that I could look for a USB cable with all that resolution, and also the correct tonal balance to boot. Or perhaps drive a D-D convertor through my original USB cable and then drive the PS Audio via coax or something else. 

Huh.... 

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. 

I got a hold of a Cardas Clear USB (the top of the line Cardas USB, $450 new) and it works beautifully with the PS Audio. Good resolution, beautiful timbre, and all the bass and brightness problems are solved.

In the previous comment I mentioned an iFi USB cable. That was okay, but after listening for a few hours, it was clear it lacked beauty of timbre and it was grainy on piano.

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

@audphile1 I did put Igor's best PC on it. The members of the N.J. Audiophile Society tell me it can compete with $5K power cords. Of course this might be introducing Igor's signature again, but I don't think so, because the weirdness all went away with the USB cable switch. 

I listened for a while through two different headphones -- LCD-2 (pre-fazor) and 2021 LCD-X. The LCD-2 is dark, and not a good match for the PS Audio.. it just sounds rolled-off with this combination. But the LCD-2 has a very beautiful midrange, and that came through clearly. I also listened to the PS Audio on speakers and noticed the extraordinarily beautiful midrange and deep musical expression - and like you say, it does require attentiveness on the listener's part, because the PS Audio isn't exactly "grab ya by the collar."

I then listened through the LCD-X, which has a much better overall tonal balance, something generally true of Audeze's fazor headphones. The sound was more interesting and attention-grabbing with the highs no longer rolled-off. But unfortunately there wasn't as much musical expression. The fazor LCD-X has a less beautiful midrange than my LCD-2. I couldn't go with the LCD-X for my long-term listening.

I then switched to my Gustard R26 with the C26 clock. The sound was much more lively and a better match for the LCD-2. In testing the PS Audio and the Gustard, I listened to Maria Schneider's "Walking by Flashlight" for big band, which builds to a climax on a beautiful, very rich/complex chord near the end. The PS Audio emphasized the beauty of this chord. The Gustard emphasized more the climatic nature of it, giving a better sense of shape and finality to the piece.

Because the Gustard is a better match for the LCD-2 (and at this time I don't want to start a whole new search for the perfect headphone), and because I find it more important to make climaxes exciting, I think I'm going to go with the Gustard, which by the way is much improved with the Cardas USB and the C16 clock. I started this thread complaining about the Gustard R26, but it seems pretty resolved. It still needs more oomph, especially in quiet music. My goal is to make quiet music, and sudden pianissimo, as captivating as loud music. (Something true of live instruments.) Maybe a better clock or clock cable.