Calculation of effective mass of JMW10 tonearm?

Sorry to be slow in thanking everyone for their suggestions. My computer network was down. I got way behind on everything.

I did contact Mike at VPI, John and Ken. That was a good suggestion. Doug, your memory of the effective mass of a JMW 10 at around 11 was very close. Mike says it is 10.3 grams. And, Carl, I ordered and then set up my arm with the lightweight dropped counterweight and the headshell weight. Although when I weighed mine it came in at just shy of 5 grams instead of 3 grams.

In any case, the JMW 10 with the ZYX R100FS (silver Fuji) sounds fabulous. It is so very quiet and clean. I am very, very pleased.

Jon

Jon, I have a Yatra cartridge, and spoke to mike just a wweek ago about the same situation. He is sending me both the headshell weight and lightweight drop counterweight, for $60, and his recommendation was exactly as Kehut stated.
I'm sure he'll do the same for you, just contact him .Very pleasent guy to deal with.
Carl

Kehut nailed it.

I haven't used a ZYX on a JMW, but VPI/Mike's suggestion to use both their 3g headshell weight and a lighter c/w mounted further aft sounds right to me. I have this vague recollection that the eff. mass of a JMW-10 is around 11g. If that's so then Mike's advice is spot on.

If you want to measure your resonance frequency, the HFN&RR test record has tracks specifically for that purpose. You'll be able to confirm resonance in both vertical and lateral modes to the nearest 1 Hz or so. A ZYX has different vertical and lateral compliance, so the resonance frequency will be slightly different in each mode.

Jon-

I seem to remember asking that same question to Mike at VPI several years back. Now, I cant remember what the number was off hand. Unfortunately, the JMW 10 manual doesn't specify as you are likely aware. As Jmcgrogan2 suggests..place a call or email to Mike @VPI for that info to help you. At times..Harry will be on the other end to chat.

As an owner of the Aries 2-JMW10 with a ZYX R-100 Fuji Silver H..I can unequivically say that this cart is MARVELOUS with that arm!

BTW...one thing that you may have already noticed is that due to the light 5g weight of that cart..you will need either a lightweight counterweight for the 10 arm or use the VPI supplied 3g headshell weights. Mike at VPI actually suggest using both together, even knowing that it will put the CW a little further back on the arm. I use only the new dropped lightweight CW and that works great. The Fuji is not avail as you know with the SB option as on the Airy models..otherwise that would have done it.

Happy listening! ;) ...Ken

Why not ask VPI? I've always found they offer very good customer support.

VPI Contact info

Cheers,
John