2. analog
  3. 1289490207

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
actusreus
733 posts
 
JMW-9T's effective mass is 9.5 grams according to Harry's email to me. 7.7 grams sounds very inaccurate to me.
audiofeil
4,011 posts
 
You can't squeeze blood from a stone.
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.
franks
151 posts
 
I used a VPI JMW 10 with a Koetsu Jade for many years so perhaps I can help here.
First of all, a compliance of 15 is not a low compliance cartridge. It is squarely in the medium catagory. Low compliance is usually considered < 10 such as a Koetsu and denon 103 which have a compliance of 5.
Have you actually listened to this combo and found it wanting or are your concerns coming from some sort of math model? The math formula's are just guidelines. Their are many combinations that are poor math matches that sound great in reality.
IMHO, the arm would work fine with your cartridge. Adding the 3gm aluminum weight is probably a good idea to get a more ideal mathematical match. Another way to do this is to buy brass screws for the cartridge which will add which will add 3-5 gms over the typical aluminum screws.
My Koetsu sounded pretty good in the JMW 10. The stone bodied Koetsu's are 4-5 gms heavier then their wood bodied "cousins" so I was adding weight without doing anyhting extra.
Regarding damping fluid, with a true low compliance cartridge, IMHO, no damping fluid is needed and that's I had mine setup. Usually, VPI recomends damping fluid only for high compliance cartridges such as Grado's or older Clearaudio's(new?). You might want to try it with no damping fluid at first and then add a drop or two and see if you like it better.
Lastly, the Triplaner is a great tonearm but it is not ideal for true low compliance cardtridges. It is on the low end of the medium mass arms with an effective mass of around 10.5 gms. That being said people have used it with a modified Denon 103 with good success. It would be great with your cartridge but I don't think you would be hearing everything your paying for until the cartridge and table got upgraded.
Enjoy the listening and the process. Hope this helps.
tzh21y OP
1,654 posts
 
Thanks for the insight
More to discover