I have not noticed sound degradation after years of use. Close inspection of the back of the planars can show some de-lamination of aluminum foil which I assume is from heat, but I have not noticed corresponding degradation in sound. You may want to verify that nuts/screw have not loosened up which will usually cause a buzz. They should be snug.
With planars no longer being available replacements/spares are possible through purchase of MM-700, MM-702, MM-2000 Monsoon speakers and then modify as Brian did. I have written a few posts on how to do this, by knowing what to look for by physical and electrical characteristics and then how to modify.
https://www.audiocircle.com/index.php?topic=96150.msg1842979#msg1842979 (post #5). It takes time and patience to find the right panel on eBay, but certainly can be done. I have purchased and modified some 18 Soncics/Level 9 panels over a couple years, for spares and an RM-V60 project.
https://www.audiocircle.com/index.php?topic=170897.msg1813464#msg1813464 (post #9).
The gentlemen in the Bay area who purchased the rest of the VMPS inventory had some new panels for sale. He is on Craigslist and they were $125 each and did not appear to have been modified (rivet removed, and screw/nut washer installed).
https://sfbay.craigslist.org/eby/ele/d/pinole-vmps-ribbons-neopanels-new/7303108834.htmlPS You could test the drivers individually. They are wired in series so you could remove two of the drivers by either putting a 6 ohm resistor in place of two drivers and test or just jumper past them without 6 ohm. If I recall the positive comes to top panel, so you would remove the negative lead from that panel going to positive lead of center panel and then jumper to negative lead of top panel to negative lead of bottom panel. From there run some sine waves (or music) and listen or better yet run some sweeps using Room EQ Wizard (REW), then move panel and repeat with next panel, and the next.
PSS Just looked at the schematic and the positive is going to bottom panel not top. That said, an easier way to test the panels individually (to minimize removing connections) is to put a jumper across the two terminals of the other two panels. To test top panel put a jumper directly across the plus and minus leads of middle speaker and a jumper across the plus and minus leads of bottom panel. Then test. Remover power and move jumper from middle panel to top panel to test middle panel, same method for bottom panel. This ONLY applies to the RM-30 which are wired in series and NOT RM-40 or RM-V60 where the panels are a combination of parallel and series circuits.
