2. analog
  3. 1269982038

MintLP Protractor for the JMW-9T tonearm

I was just about finished with my order of a MintLP protractor for my Scout's JMW-9T tonearm when an issue with the geometry of this particular tonearm arose. Yip from MintLP at first assumed the tonearm was the regular JMW-9, which has the same effective length as the Signature version. When I sent him a link to the description of the 9T from the VPI website to make sure he knew it was the upgraded version, he said he had made a mistake as the description stated that the 9T had the same geometry as the Rega RB-300 and could be dropped onto any Rega armboard. He suggested I contact VPI to get a definitive answer about the 9T.

So I did contact VPI and they responded that the 9T indeed has the same geometry as the Signature and the same as the Rega. So I'm now a little confused why Yip seemed to think the Rega RB-300 and the JMW-9 have different effective lengths? Is anybody familiar with the above mentioned tonearms and can confirm either way to settle this? I'd hate to waste over $100 on a custom made protractor if it's made on a wrong assumption.

Thank you.
actusreus
actusreus OP
733 posts
 
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.
dougdeacon
3,338 posts
 
The clear answer with regard to VPI tonearm geometry is that VPI has consistently refused to provide clear answers. That has always been the case. :-(

The article Todd linked was a great piece of research. Does it apply to the 9T? Only more research will tell.
istanbulu
291 posts
 
Actusreus... if you are still interested in pursuing this very frustrating matter in order to properly setup your tonearm, my experiences with Yip and his BesTractor and other products tell me that following his knowledge and advice might be a preferred course. I have had excellent experiences with him, his products, and his social and communication skills.

After all, he is the one who creates and sells these excellent products, and I have no reason to think he wouldn't stand behind them.

Sure... this logic also applies to VPI, but the little guy (Yip) has more to lose with a single dissatisfied customer than the big guy (VPI) with a world class reputation and thousands of customers and hundreds of dealers.

My best suggestion is to discuss this with Yip, follow what he says, and if he sells one to you arrange it on a customer satisfaction basis. Also, for the sake of all of our madnesses in this hobby, report back your experience for our greater edification.

Just my thoughts and experience. I hear yah... these sorts of things make the love of vinyl tough...

:) listening,

Ed
stringreen's avatar
stringreen
6,368 posts
 
I forgot where I read it, but I seem to remember reading somewhere (I know this doesn't help) that the Classic arm was just slightly lengthened. This would affect your setup. It very well may be that the arm now conforms to the Rega dimensions as VPI says, but then again it may be which arm you have if indeed the dimensions were changed. I have a 10.5i, and set it up with a MINT, and the setup sounds better to these ears with the MINT.
actusreus OP
733 posts
 
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.
More to discover