MintLP Protractor for the JMW-9T tonearm

I am more than happy to report back so that we're closer to the "truth" (in this case the truth being the parameters that should be used to offer the optimal cartridge alignment with the VPI JMW-9 tonearms):

My measurements of the mounting distance for the JMW-9T confirm the findings in the linked article from vinylengine, at least when it comes to the mounting distance, i.e., it is 222mm, and not 223mm as VPI stated on their website before removing this information altogether. If so, protractors from Mint for this particular tonearm are theoretically not correct since, as Yip indicated, they are machined with the assumption the mounting distance is 223mm and the effective length 240mm to conform to the Baerwald algorithm, which Yip uses for his protractors.

Based on the mounting distance of 222mm (which btw is the same as for the Rega RB-300, which VPI informed me had the same geometry as the JMW-9 tonearms), the effective length under the Baerwald algorithm is 239.5mm and not 240mm, which has been the target for Yip until now. So if my measurements are correct, JMW-9 tonearms set up with the Mint protractor might actually not be set up optimally. How big of a difference are we're talking about? I don't know, but I would very much like to find out.

My protractor will be shipped April 10, and ideally I would like to set up my cartridge using both protractors to compare the result and ultimately determine which one is more correct. If anyone has a Mint protractor made for their JMW-9 tonearm and is willing to participate in this experiment, please contact me.

Actusreus... I'm not sure of or completely clear on the implications your posting on 04-02 might have for someone like me who has a ScoutMaster with the stock JMW9 tonearm and uses/has used the appropriate "9" Mint LP Tractor to set that up. Can anyone clarify as best they know/understand Actusreus' post?

:) listening,

Ed

Istanbulu,

The Mint protractor for the JMW-9 tonearms is made based on the mounting distance of 223mm and effective length of 240mm based on the Baerwald algorithm, which Yip uses for his protractors. The mounting distance of 223mm is what VPI used to officially state on their website before removing it. That's why Mint has been making their protractors based on these numbers. However, the vinyl engine article linked in the first response reports that the actual mounting distance on the JMW-9 is 222mm, not 223. I measured mine and it indeed appears that it is 222mm. This would also comport with what VPI told me in response to my email, i.e., that the JMW-9 has the same geometry as the Rega RB-300, which has the mounting distance of 222mm. If so, the protractor for the JMW-9 tonearm should be made based on the mounting distance of 222mm and the effective length of 239.5mm under the Baerwald algorithm, and NOT 223mm and 240mm, respectively.

That is why I wonder if the JMW-9 protractors are actually correct. Because VPI refuses to reveal the actual measurements, it is difficult to determine exactly what numbers the protractors for VPI tonearms should be made based on. That's why I wanted to try a set-up with both to compare.

Hope this clarifies my previous post.

Actusreus... thank you, and I was afraid you might actually be saying what you said (if that makes any sense!).

So at this point I wonder what to do. I wonder what the net musical effect of this might be.

Earlier today, I sent an email to Yip alerting him to this thread, and I hope we all hear from him. He strikes me as a straight-up guy who wants to get it right and do the right thing.

Now as it relates to VPI, it sure would be helpful if they joined the discussion in a transparent and informative manner as well... jmo and hope.

:) listening,

Ed

First off, Yip has been extremely professional and helpful. I have no doubt his product is the best of its kind out there. I would hate to give even a hint of impression that he has done something inaccurate or incorrect, when quite the opposite is true. The blame for anything rest with VPI that has been rather unhelpful by not providing accurate data for their product, which is necessary to get the best out of any analog system.

I now almost regret I started this thread as I fear it might be causing more harm than good. I wanted to get an advice but it appears it has opened the proverbial can of worms and for this I blame myself as well and I apologize.

As for your question, Istanbulu, if you have been happy with your system, continue enjoying your system! My Scout was set up with the VPI jig that is inferior to Mint protractor and without a magnifying glass. And guess what? I love it! I wanted to use Mint to make sure I'm getting the best out of my cartridge, but that doesn't mean I can't be enjoying my music without it. If it sounds good to you, it's all that matters.