Heard it a few times at Jolida headquarters in Md. Both the original version and the upgraded (better caps and different volume control) don't remeber what the volume control difference exactly was, but it makes big difference suposedly. Not really an expensive upgrade either, think it was less than $100, new versions may include this revision, call Jolida if curious.
Really nice for the money. Bass and ulimate volume being limited. This is no BS, I was blown away by the upgraded version driving the Mbl mini monitors. Maybe because it worked at all

Big stage, nice detail, focus and texture. Serious price mismatch. They handle the Nola monitors no problem either.