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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
markpao
519 posts
 
I've been using a Benz cartridge with my VPI setup for a while now and they are a
very good match. Dynavector's also work good with VPI. It's my understanding that high compliance cartridges is the way to go with these tonearms. Enjoy.
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.
cmalak
681 posts
 
Tzh21y...do you know how much your Benz cart weighs?
tzh21y OP
1,654 posts
 
9 grams
cmalak
681 posts
 
If the JMW 9 tonearm is indeed 7.7 grams effective mass and the Benz cart's weight is 9 grams and compliance is 15, then the calculated resonant frequency is 10Hz, which is exactly where you want it to be (acceptable range is 8 - 12 Hz). If the JMW 9 tonearm effective mass is closer to 9 grams (as per your discussion with Harry), then the resonant frequency with your Benz cart is 9.7Hz, so either way, your Benz cart should be a good fit. Hope this helps.
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