2 cents:
I've always been a proponent of "garbage in = garbage out" My quest for sources have ultimately led me to the Chord Hugo 2, I was previously running a Curious USB cable via/jitterbug out of a macbook pro. Now, I know there are a lot of cable naysayers, but USB cables are a whole 'nother story, I'm not touching this with a 10-foot pole in this thread.
Anyways, I was at first extremely skeptical of any of these jitter reducing devices, they truly seemed like snake oil to me at first. After doing a bit of reading on head-fi, and thus emptying my wallet more because what the heck an Audioquest Jitterbug is a relatively low-cost upgrade in our hobby. I instantly noticed a difference when I first plugged it into my chain (then was a Chord Mojo,) but I don't know if I liked it, it made the already warm Mojo sound extra aggressive (I also had Vega's at the time, talk about bass overload). I did some more reading on the interwebs and Rob Watts himself states that he hears differences with the Jitterbug when plugged into his chain (not a Mojo, Hugo 2 me thinks). Like I said, there are a lot of naysayers out there, but I can hear a difference and I'll let your ears be the judge of your own gear.
More audiophile rabbit-holing led me to the Uptone ISO REGEN and Uptone UltraCap LPS 1.2. I'm not gonna go over the specs in detail here but essentially it reduces noise and jitter from the crap that my Macbook produces. It's powered, unlike the AQ Jitterbug, and it's also 10x as expensive (including the LPS 1.2) Do I hear 10x the improvement? Hell naw, we are well into the law of diminishing returns at this level of headfilia, but screw that we are here for the soundssss.
My old chain: MBP > AQ Jitterbug+Curious USB cable > Chord Hugo 2.
My current chain: MBP > Uptone Iso Regen/LPS1.2 + micro-USBCP > Chord Hugo 2.
With the new upgrades, I instantaneously noticed a difference, and my first impressions were: goosebumps. The background became a lot darker. Separation/soundstage/imaging all improved. The highs were probably the first thing I noticed that sounded quite a bit better. The attack and decay on cymbals is unlike anything I have ever heard. Everything was just so much "tighter", the attack, sustain, decay, release, ugh. I then shifted my attention to the mids, same thing, the
prrrrrrrat makes me go
ughhhhhh moreeee. The individual snare hits, cymbals and ohhhh the sustain of the synth in Pendulum's - "9000 Miles," a track I've listened to thousands of times, but I think the synth touched me for the first time.
I've got a pair of EE Legend X's, and the bass actually tightened up quite a bit. I was getting quite a bit of fatigue when listening to techno and house via a PW Audio 1960's cable, but I've just finished listening to Fabric 77: Marcel Dettmann, and I'm about to throw on some more Fabric mixes
The bass is probably the least improved upon area after initial listening, relatively.
I'm still waiting on a Curious cable to replace the stock Uptone one, as well as a Sonore DC cable, aaaaaand a set of PW Audio 1950's. Will update with more once everything is nice and burned-in.