To avoid spoiling the non-linearity and mechanical threads, has anyone read anything about the cartridge generator aging?
We know rubber parts go off, but what about magnets losing strength and pole piece permeability going down? Steel certainly had problems with magnetic domains growing, so Permalloy might do the same or suffer from surface oxidation
We know rubber parts go off, but what about magnets losing strength and pole piece permeability going down? Steel certainly had problems with magnetic domains growing, so Permalloy might do the same or suffer from surface oxidation
Wet playing could cause metallic parts (permalloy and others containing iron) oxidize. So can do wiping the needle with wet brush. There are several steel parts inside.
Some magnets do lose strength and if you get some MCs rebuilt they will often re-magnetise them. How much they actually weaken compared to say a classic alnico speaker I really do not have a handle on. I do notice no one offers a NEO upgrade on their cart rebuilds. Maybe an opening in the market 🙂
For MM the magnets could weaken but again no handle. As for pole piece oxidation that is a very interesting question. Generally they are wrapped in enamelled wire and laquered to hold everything in place so oxygen should be kept well out. If things have been reactive enough to damage that, then the suspension will certainly be shot.
Also not sure how one would measure this other than some severe accelerated aging tests. I do have some 30 year old cartridges but UK climate is fairly benign.
Interesting question 🙂
For MM the magnets could weaken but again no handle. As for pole piece oxidation that is a very interesting question. Generally they are wrapped in enamelled wire and laquered to hold everything in place so oxygen should be kept well out. If things have been reactive enough to damage that, then the suspension will certainly be shot.
Also not sure how one would measure this other than some severe accelerated aging tests. I do have some 30 year old cartridges but UK climate is fairly benign.
Interesting question 🙂
I would expect magnet or permeability changes to show in output level, maybe also the typical MM 5kHz droop might worsen.
I don't trust "cottage industry" cartridge makers to have taken long term corrosion into account at all
I don't trust "cottage industry" cartridge makers to have taken long term corrosion into account at all
I had a 1961 Audio Dynamics Corp R-10 that in 1970 tracked like a dump truck before power steering with a new stylus. Would jump out of the groove on Atco's I Wonder What She's Doing Tonight. It was replaced with a Grado FTE that shed a chunk of diamond in 1978. That was replaced with a Shure M97 Era IV which I'm still using with no symptoms except a flattened brush. The diamond looks pretty good. Level? I'm still listening about 10-11 oclock on the same preamp and amp, (Pas2, ST70) but power supply and paper caps have been replaced, as have numerous rectifier and power output tubes. The volume pot has been replaced too. So I don't know if absolute level deteriorated or not. Speakers didn't last 39 years, either. Bottom line, I'm thinking of buying an M97Xe to replace the brush on the 1979 Shure M97 era IV- very long lasting component last time.
On the receiver end the ears were tested okay to 14 khz in 2008, and I've been out of factories since then, so probably I still have the same. The big high end loss occured one day in 1969 at ROTC summer camp when I fired the howitzer.
On the receiver end the ears were tested okay to 14 khz in 2008, and I've been out of factories since then, so probably I still have the same. The big high end loss occured one day in 1969 at ROTC summer camp when I fired the howitzer.
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