Thanks. Please do not misunderstand me as I in no way expected you to have "super expensive" USB cables but I would have thought any quality made commercial ones would be at least a benchmark.
There's a Shakespeare saying which ends with 'doth protest too much' which comes to mind, but to give you some background, the first iteration of a DIY USB cable was prompted by ideas seen in two products, one by Light Harmonic, and one by iFi themselves.
Again, no offense but what comes with the iFi (I know it well) and any off the self USB cables should be easily improved upon.
Then, by all means, go ahead and do it yourself and find out. You can get jumps in SQ with simple modifications for sure (did that a couple of years ago). Furthermore, that is also the point which is inherently valuable in itself: too many times, people (including me) satisfy themselves with the default solution - 'It just needs power, let's plug it in...', 'This requires a USB cable, let's plug it in...'
By how much is a guess, including yours as you have no known benchmark to compare it to.
On the contrary, if you had actually paid attention to what I said in my previous post, my benchmark is very clear and really simple and really one of the most well-known benchmarks ever: it is the default solution, which is what most people use taking either the USB cable which comes with the device or an off-the-shelf USB cable, which is also often a cable lying around unused.
This is unfortunate because you might have exceeded many highly regarded, and worthwhile, USB cables...or not.
It would be unfortunate if my goal was to compare with those commercial, improved cables, but that wasn't my goal at all - my goal was to see how much I can optimise my own system with little means but an understanding of the whole chain.
It appears you assume I only did one simple change in my USB cable. This is far from reality: I must have reached version 12 of it these holidays until I obtained a configuration with which I am quite satisfied (there are probably a handful of additional revisions I could do to it with potential benefits but I expect them to be incremental as the 'flabbergasting' has already occurred in 3 steps). Actually, now, I hesitate to call it a cable, as it has circuitry and an unconventional design, so a better name is a "USB Connection".
I have had to totally re-think what a proper connection for async USB audio should be ideally (instead of using USB for the usual data transfer or low-speed peripherals).
The insight gathered while researching, designing, building, listening, iterating and re-listening is invaluable, and something you don't get from buying cables left and right.
NB: I presently wouldn't be against finding out if my connection could be better than some of the commercial offerings and I am fairly certain it beats some of them as I actually compared various similar architectures here, but the process would have to be easy - I certainly won't go buy one to compare (
or the several devices + cables that my USB Connector replaces but which you would have to buy individually) as I am satisfied with my SQ here and the results I have obtained.
If you get the chance to borrow some commercial USB with the appropriate time to compare that would great.
One audiophile friend I believe has an Audioquest cable, so maybe I could borrow it, but I haven't seen him in 2 or 3 years. For logistical reasons, it's hard to get him to visit.
Then, of course, come the ability, or lack thereof, to share the listening experience (with or without comparisons to existing commercial designs other than the default) and also, the ability or lack thereof to make measurements which could show where the benefits could lie.
I am actually thinking of bringing my things over to some friends' places and test in their system at one point - that could be a fun thing to do, but frankly, I'd rather they drop by themselves, as I'm too busy researching and refining the Linear Regulated PSU, it's a super-low impedance design for my DAC and it's really, really good, especially since the 12th where I reduced output impedance, noise and ripple to really low levels all in one revision.
That is some report. 
