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 should call VPI and ask for the effective mass of your tonearm. There is a bit of confusion on this because VPI has had variants of the JMW9 and JMW10.5i tonearms depending on the material used in the armwand (aluminum vs stainless steel). I believe the 7.7 grams effective mass for the JMW9 measurement is for the aluminum wand. You should get the effective mass of your specific tonearm and then just use the calculator on this page (Freek's Resonant Frequency Calculator) for tonearm-cartridge matching:

What is the weight of the Benz H2 cartridge?
I have never found a Benz cartridge that doesn't work in a VPI arm. Its easy to get upset about things like this, but I'll bet you're fine. Install the cartridge and listen and enjoy.
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.
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. you know how much your Benz cart weighs?
9 grams
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.
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.
Try a bit of damping at the pivot.
JMW-9T's effective mass is 9.5 grams according to Harry's email to me. 7.7 grams sounds very inaccurate to me.
You can't squeeze blood from a stone.
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.
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.
Thanks for the insight
How about Van Den Hul cartridges? Which version should I get for my JMW9 arm? (I am also planning on upgrading it to a 10.5 arm, unless anybody else could tell me otherwise.)

I am also looking at Zyx cartridges, which I think would be a better match for the JMW arms?
Toufu, you should also consider the Dynevector and Lyra lines of cartridges. Both work extremly well in the VPI arms.
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.