A lot of the harshness of the combo comes from USB interface. Reclockers dramatically change performance of jot dac. You can clearly hear akm velvet signature with a good reclocker in line. It's significant, especially since jot dac is fully USB powered, something like regen or W4s recovery allows you to slip in your own 5v power, an ifi ipower in my case
That said, some people really dislike akm velvet. I don't mind it, but I couldn't really hear the signature pre reclockers, after it was obvious.
For those that don't know velvet is marketing speak for the way the dac chip designer voiced the 4490.
There was a significant change to the voicing of akm post velvet.
http://www.akm.com/akm/en/product/featured/velvetsound/
I use a belkin gold USB (with 5v taped) to a W4S Recovery powered with a 9v ipower brick to the Jot USB. There were improvements st each step, the biggest was the recovery, then the power supply, and I'm not sure I heard a difference taping the 5v pin on USB, but it's a free 5 min tweak. I purchased the recovery used, they can be had for around 100$. It's a tweak I will carry forward when I eventually move to mimby/bimby but I feel no great rush as these tweaks really improved things.
USB tweaks are always a ymmv because everyone's system is different. For my system the change was significant, I considered wyred but I believe regen or recovery a superior, I think they both use a much better crystal, the recovery uses a Femto clock.
If your buying new I do recommend skipping the dac and going straight for mimby, but if you already have the jot Dac, a regen or recovery for 100$ or less is a good value and will carry forward to new dac
Edit: in case it's not clear the regen and recovery do come with their own 5v power supplies witch replace your pcs USB power, but you can also replace those with higher quality units, witch may not matter if your dac
Is not USB powerd, but jot is so the tweak pays dividends here, the ipower is the cheapest one I could find (50$) that is worth upgrading to