On the Dynasty and I think the 250EXT has it too, control knobs to adjust the AC amperage meaning separate amperage controls for electrode negative and electrode positive along with extended ac balance (Time).
During the time I had on a Dynasty, I never adjusted the amperage controls because the welder was used only to weld one part and it was used by two other welders besides myself.
Maybe Gunner can answer my question, Does welding aluminum with 20% electrode positive and 80% electrode negative weld exactly the same as the AC balance on 20% electrode positive and 80% electrode negative?
All welders will adjust to too much electrode positive on the AC balance, of course that burns up the tungsten and glows the cup cherry red and then you through it all in the trash. It would be nice to have the ability to adjust the electrode positive down to the point to where there is not enough cleaning action to leave a good clean weld, only then could you adjust the welder to have the most focused arc and balance it out with the minimum amount of electrode positive needed.
I have found extended AC balance is more important than high frequency, but it is an option I do still want.