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JMW 9 effective mass?

I read on vinyl engine that the effective mass of the JMW 9 is 7.7 grams. If this is true, that would make the JMW 9 a LOW MASS arm. My cartridge is supposed to be used with Moderate to High mass arms. Its compliance is 15. I think I have a mismatch. Why doesn't VPI publish this information so I would not spend $1,500.00 on a cartridge that sounds wrong on my table. I have a Benz H2.

I was told that my arm is in fact a moderate mass arm. Well, where are the specs indicating this? I want to see for myself. If I have a low mass arm, I should be using high compliance cartridges, correct?

Where do I get this information, it did not come with my tonearm, it just had information on installation

What is a good High compliance cartridge?
tzh21y

Showing 7 responses by tzh21y

tzh21y OP
1,654 posts
 
9.5 is correct. LOL You are right Audiofiel. I am not willing to accept reality. I may be at the limitations of my cartridge, tonearm, preamp. I wonder if you can mount a Triplanar on a Scout, probably not worth it. Maybethat would not even do it.
tzh21y OP
1,654 posts
 
VPI (I believe it was Harry) did tell me that it is a low mass arm somewhere around 9 grams and recommended a headshell weight. He said 3 or 4 grams should be sufficient. I guess Elusive disc has them. He said the difference will be very noticible. I shall find out. The compliance of the Benz is 15 and is recommended for medium to high mass arms.

He also told me to heat the cartridge with a lamp or blowdryer prior to listening. That is what he does with his Benz. I knew there was something that just was not right.
tzh21y OP
1,654 posts
 
9 grams
tzh21y OP
1,654 posts
 
On the cartridge specifications, it says for best performance, it should be used with a medium mass or high mass arm. I have read that anything below 12 grams is low mass which is what the JMW 9 is. So it should be mated with a higher compliance cartridge, am I wrong? I have also read that 15 is medium compliance. I will check into the resonant frequency. How do you calculate it? VPI told me to get a headshell weight which I am pursuing. I have added weight to the tonearm (4 grams) and it has made a difference. Backgrounds are quieter, images are more solid, massed violins have more definition and do not sound smeared, it is much better. When I get the VPI headshell weight, it will probably even get better.
tzh21y OP
1,654 posts
 
Thanks for the insight
tzh21y OP
1,654 posts
 
Added a 3 gram headshell weight and it made a big difference in tracking. Bass is better and a more solid image. After adding the weight, I would say it it seems as though the weight is a necessity with the benz H2 and teh JMW 9 tonearm. I was tracking at about 2.2 grams. I can track at a lighter setting with better results. I am glad I got the weight. I needed a deeper set of cartridge screws. It sounded horrible withthe original screws.
tzh21y OP
1,654 posts
 
I am using a newer JMW 9 arm on my scout and I would say it has a higher effective mass than is specified.  Its sounds great with a Lyra Delos.  I have the Stainless steel arm tube version.  I think its a match made in heaven
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