Dertonarm, I never question the reports of others' personal experience(s) except in those (extremely rare) instances when I've had the same experiences only with quite different outcomes ;-)
I also think people need to be careful when assuming certain cause-effect relationships; and that they are responsible for the things they observe.
Because you observe that some cartridges you've worked with perform to spec right out of the box, doesn't disprove my assertion that there is a change, over time, in the elastomers; which there most definitely is, even in modern suspension materials, and especially for the cartridges you mention.
Most new (or even old) MC cartridges, unless they're defective, will perform "within a very narrow window within specs", as you put it, at a variety of loads and VTF settings. So what? I can easily make a brand new cartridge sound 100 hours old by loading it too high and applying a bit more VTF which will increase frequency response at the top and bottom until the suspension limbers up. I choose not to do that however knowing I'm going to have to do it all over again in 100 hours ;-) And because I enjoy hearing a cartridge going through its changes.
None of the three cartridges you mention are typical MC cartridges. They ALL have extremely LOW compliance, even for a MC (5 as opposed to 30 for most MC cartridges) and they all have HIGH VTF specs (3.5 to 9 grams!, as opposed to 2 grams for most MC cartridges.) So it's unlikely you'd hear any performance difference between brand new and 100 hours old, with any of those cartridges. In addition, those three cartridges are very low output and IMO not up to current performance standards ;-)
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I also think people need to be careful when assuming certain cause-effect relationships; and that they are responsible for the things they observe.
Because you observe that some cartridges you've worked with perform to spec right out of the box, doesn't disprove my assertion that there is a change, over time, in the elastomers; which there most definitely is, even in modern suspension materials, and especially for the cartridges you mention.
Most new (or even old) MC cartridges, unless they're defective, will perform "within a very narrow window within specs", as you put it, at a variety of loads and VTF settings. So what? I can easily make a brand new cartridge sound 100 hours old by loading it too high and applying a bit more VTF which will increase frequency response at the top and bottom until the suspension limbers up. I choose not to do that however knowing I'm going to have to do it all over again in 100 hours ;-) And because I enjoy hearing a cartridge going through its changes.
None of the three cartridges you mention are typical MC cartridges. They ALL have extremely LOW compliance, even for a MC (5 as opposed to 30 for most MC cartridges) and they all have HIGH VTF specs (3.5 to 9 grams!, as opposed to 2 grams for most MC cartridges.) So it's unlikely you'd hear any performance difference between brand new and 100 hours old, with any of those cartridges. In addition, those three cartridges are very low output and IMO not up to current performance standards ;-)
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