Now, the USBridge Sig falls precisely in the category you describe, and from the looks of it, there’s at least as much custom, audiophile-targeted engineering work that went into that than into any Rendu. Have a look at it.
It’s chock-full of low-dropout regulators (not a sign that it’s inherently any better than the switching regulation on the Rendus), and it’s powered by something that, on paper, makes a fraction the noise of a Nagra HD DAC-X.
Now, let’s have the same cursory look at the UltraRendu. Let’s take the board.
That looks quite a bit like a certain SolidRun device, don’t you think ?
Only the marketing there touts exactly the opposite of what you’re putting forward as a way to fight EMI, which is its “small size” (I’d add “rightfully so”, because it’s half the size of the compute module on the USBridge, but that’d be petty so let’s skip over that). Anyway, I’d wager we can safely assume that the brains of the UltraRendu are not some purposed-built device, which’d naturally be extraordinarily difficult to achieve for a company the size of Sonore (or any audiophile-market company, though IIRC SoTM does their own grounds-up, audiophile-targeted designs). It’s more likely they, just like Allo, took the smarter approach, which is to figure out something that you can use as the brains to a really nice, really clean design (which the UltraRendu certainly is), and use your ressources and energy to focus on that.
The one huge difference ? One retails for a grand with a linear PSU of unspecified capabilities or measurements (this isn’t shade, it’s that I think these should be published), and is backed by apparently fantastic customer support, and clearly fantastic customer engagement. The other retails for less than half that, PSU included, with published graphs that back up superlative claims.