Hi Jazzman, it looks that the Licron Crystal coating has lasted a little over a year and is now failing. I have to really bump up the preamp for the panels to sound just ok and still muffled. Visually the coating looks fine. Its happened to both speakers so I assume it cannot be the electronics and has to be the coating on the panels. If i rebuild the panels, this time I will use pre-coated mylar. It is available but not easy to source due to thickness and quantity. Else I've read that metallised mylar may also work though visually is not appealing. Hoping to hear some of your thoughts. I'll ask JonFo too about increasing the voltage. Maybe that would help.
I’ve only just seen this post or I would have responded sooner.
I’ve recommended Licron Crystal on my website for some years now, so I feel a certain responsibility when someone reports poor results with it, as well as a desire to figure out why.
Although I’ve used Licron Crystal for almost a decade on about 12 pairs of panels; I’ve given away my older ones and haven’t kept up with those. The oldest pair that I can personally attest to are 5 years old and their owner is happy with them. My personal pair of MkIII’s were completed in Jan. 2020 and I haven’t noticed any degradation in their output to date. Several of my audio buddies also have them (with my warranty) and have not reported any problems.
My friend Martin owns the MkIII prototypes (5 years old now) and their output measured 3-4 db lower than my newer/improved MkIII’s, when we compared them recently. We attributed the difference to the prototypes’ lower biasing voltage (2.7kV versus 3.3kV) and higher resistor values in the segmentation network (130kOhms per segment versus 107kOhms per segment x 8 segments). However; I can’t know for certain that all of the difference is due to aforementioned power supply components.
Several of my friends have speakers I built for them using Licron Crystal, and I’ve given them a lifetime warranty on the panels (my lifetime, not theirs), so it’s concerning to read here that others are reporting problems with the longevity of the Licron Crystal.
I’ve read conflicting reviews on the Staticide coating as well, some have reported very good results with it. The manufacturers (Staticide and Techron) advertise them as permanent coatings but then again, I doubt they tested them using the kind of continuous charge applied by an ESL bias supply.
I’m also wondering if variables in the application method, environment, playing hours, etc… could affect the coating longevity. In this regard; I can only say that I always apply the coating inside my air conditioned house rather than out in the garage due to concerns about humidity. Also; I spray on a single “just wet” coat. I also use a full-periphery copper foil charge ring for the bias supply connection, rather than a local-contact connection.
At this time; I’m at a loss to explain the reported different results with Licron Crystal.
