MintLP Protractor for the JMW-9T tonearm

Oh boy, my head is spinning after reading this article. So basically there is no clear answer regarding the geometry of VPI tonearms. If so, I wonder how effective the Mint protractor actually is for VPI tables and tonearms. Owners of VPI gear seem to swear by it just as owners of other tonearms, but without actually being able to verify the effective length, mounting distance and null points, how can you actually claim that your cartridge is set up optimally? Sounds like you might as well use the VPI jig and be $100 richer.

Anyone with the new JMW-9T to prove me wrong? I'd love to hear feedback from VPI owners who have used the Mint protractor with their VPI tonearms.

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.

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.

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.

Istanbulu,
To provide you with an update:
-I contacted VPI and Mike informed me that the JMW-9T (and all JMW 9s) has the mounting distance of 223mm. So your protractor is spot on.
-I measured the distance on my rig again, and although it is very hard to measure it perfectly, it appears that it is indeed 223mm. It is rather strange as I was getting a consistent reading of 222mm before, but it might have been the height difference between the pivot and the spindle.
-My protractor will be sent with the April 29th batch and I am looking forward to using it.

Throughout this whole process, Yip has been extremely helpful, patient and quick to respond to any concern or question I had. I am very impressed with his level of customer service and professionalism.

I thought I'd provide an update as I received my Mint Tractor this past weekend and used it to realign the cartridge on my Scout.

I performed the initial set-up with the VPI-provided jig. When I checked the alignment with the Mint, the null points appeared to be aligned quite well, although I did not check it with the magnifying glass that came with the Mint. With bare eyes, the stylus looked to be pretty spot on on both null points. However, the cartridge DID NOT track the arc on the Mint properly; the stylus was about 1 to 2 mm in front of the arc close to the spindle. It is apparent then that the VPI jig does an ok job, but is definitely not precise enough to provide an optimal set-up. It took me over an hour to fix the position of the cartridge so that the stylus was sitting perfectly on the line along the entire arc drawn on the Mint, checked with the magnifying glass. And that was only half of the job!

The cantilever appeared to be pretty well centered and parallel to the two reference lines on both sides of the null points. I decided not to get into perfect alignment on the null points as I ordered the VPI Classic after I had ordered the Mint Tractor and will have to do it all over again with the new table. Also, the cantilever on my Soundsmith Aida is not perfectly parallel to the sides on the cartridge's body, so even though perfectly straight, I wasn't sure a perfect alignment between the two reference lines was even possible with the cantilever. However, it looked really good all things considered.

I then went through an extensive listening session. There was no doubt the realignment improved things. The separation of instruments improved, as did the depth and width of the soundstage. Music had a snap to it that it lacked before; it simply sounded more lively and more dynamic. Now, I'm not talking a dramatic difference; I loved the sound before, but now it became more refined. I had a sense that the Aida was also tracking better as I didn't hear distortion where I heard it before on some problematic passages on certain records.

I will no doubt be buying a new Mint tractor for the Classic tonearm. Now, if anyone would like to take this one off my hands, please let me know. It's a must-have tool for a vinyl lover.