Beetle - thanks for the link.Tmsrdg - I'll speak to the geriatric speaker problem. Yes, there are concerns, but not very centered on ageing of materials in Thiels. We paid lots of attention to longevity, our finishes have ultraviolet screening agents, driver surrounds are rubber for very long life, etc. If someone places the speakers in direct sun without the grilles, there may be some hardening/stiffening of the surrounds to raise resonance frequencies. I suggest keeping them out of direct sun and with their grilles on.
The main concern is fatigue of the tinsel leads in the drivers. We spec'd really good braided leads, but they eventually fail, especially if overheated. The CS5 drivers are presently serviceable via CoherentSource Service and/or their manufacturers. Work is being done to stabilize that service into the indefinite future. The other potential vulnerability is crossover capacitors. The CS5 is pretty bulletproof. Almost all of the caps are film, primarily film and foil, which have extremely long lives (indeterminate.) There are only 6 electrolytic caps, all in parallel shaping circuits, so their failure would be quite benign. Thiel used ultra high quality electrolytic caps with a rated service life of 40 years - but speakers generally are used far less than service ratings assume. As mentioned in the bulletin Beetle attached, storage is an electrolytic cap's worst enemy. Another hazard of old electronics is solder joints. The CS5 was when we chose Alpha's SAC305 solder which is used by NASA for space duty gear. I've never seen one fail, but retouching those hundreds of solder joints would increase peace of mind.
In short, I think that age is a problem in old speakers, but much less of a problem in old Thiels because we considered longevity in our mission.
The main concern is fatigue of the tinsel leads in the drivers. We spec'd really good braided leads, but they eventually fail, especially if overheated. The CS5 drivers are presently serviceable via CoherentSource Service and/or their manufacturers. Work is being done to stabilize that service into the indefinite future. The other potential vulnerability is crossover capacitors. The CS5 is pretty bulletproof. Almost all of the caps are film, primarily film and foil, which have extremely long lives (indeterminate.) There are only 6 electrolytic caps, all in parallel shaping circuits, so their failure would be quite benign. Thiel used ultra high quality electrolytic caps with a rated service life of 40 years - but speakers generally are used far less than service ratings assume. As mentioned in the bulletin Beetle attached, storage is an electrolytic cap's worst enemy. Another hazard of old electronics is solder joints. The CS5 was when we chose Alpha's SAC305 solder which is used by NASA for space duty gear. I've never seen one fail, but retouching those hundreds of solder joints would increase peace of mind.
In short, I think that age is a problem in old speakers, but much less of a problem in old Thiels because we considered longevity in our mission.