I guess a charge up is more an appropriate term used for differences perceived pre-usage and post-usage of any electrostat. Especially helpful for vintage stat's that have had a charge up in many years, let it charge up to let it re-bias itself to fix any deficiencies in sound such as slight channel imbalance or low volume for like 8 hours. Sound improves after a good proper charge up. But burn-in in this case, don't think so.
Back on topic. Decided to give my Gamma Pro's some headtime today as I've been listening out of the SRM1 MK2 > LP and my recapped xH > 202's. Gone back to using the SRD-7SB MK2 on speaker taps of my modded Yaqin speaker amp, talk about musicality, while these are no technical beasts like the LP combo, the Gamma Pro's on this amp sounds night and day better than when paired with the MK2 or xh and is extremely musical and resolving to listen to, the benefit of the tube hybrid amp I'm using adds on the extra weight and depth to the music. Currently using borderlining great tubes in the amp 2x Mullards CT 12AT7's and 2 60's Sylvania green letter 12AU7, both pairs all balanced and it sounds this good. Going to roll in my upper grade lot Psvane's and Amperex BB in for a change. Reminds me how much I paid for the Gamma Pro's again in NOS condition for $350 shipped org box absolute steal.