I have to say that, as an engineer, I am unsurprised that cartridge ageing data isn't readily available.Daniel Quinn wrote: ↑Mon Jan 16, 2023 3:56 pm When I worked , I was a lawyer , not a materials specialist for Ortofon.
As a lawyer , I am conversant with the value of facts. There aren't any in cartridge ageing from what I can see.
To start with it will be proprietary information which the manufacturers wouldn't release.
Secondly, almost any dedicated regular user of vinyl is likely to monitor the use of their cartridge and either replace the stylus assembly, or return the whole cartridge to the manufacturer for stylus replacement, long before deterioration of the suspension becomes a problem. If the suspension has deteriorated the manufacturer will find it and repair as required.
Thirdly, if there were a problem it is quite likely that the manufacturer would replace the cartridge/stylus assembly free of charge.
The absence of evidence isn't evidence of absence as you well know. In engineering, we regard evidence of failure in one application as evidence of the possibility of failure in other, related, applications. Therefore, we can reasonably conclude that, if the suspension uses an elastomer material it will deteriorate with age. Obviously other suspension materials are available and they may not suffer such deterioration but, without evidence of what those materials may be, we must act on the possibility that deterioration and/or failure of the suspension is possible. It should be noted that some moving coil designs use a wire suspension. Wire, being metal, can suffer from metal fatigue. The absence of facts relating to suspension failure does not actually support the contention that it cannot, and does not, happen.
In 1954 metal fatigue was an almost unknown concept yet, once it was understood, the possibility was applied to many applications beyond the DH Comet.