TNT JMW 10 Set Up Help

TNT JMW 10 Set Up Help

Postby rplace » Sat Jun 29, 2019 9:33 am

Hey all!
Long time vinyl guy first time VPI owner. Been lurking a bit and reading a lot. I'm hoping you can help me get my new (to me) table up and running properly. Based on my reading here and pictures I sent to a brick and mortar store this is what I believe I have.
-TNT 3 with hardish rubber balls for feet (I think originally springs, but long gone before me)
-Platter from a TNT 5 Derlin/Stainless
-JMW 10 arm, early version no side weights, no anti-skate, pivot spike has well for fluid, all silver except numbers on the scale around VTA which is black

I'm coming from a background of owning a Basis 1400 with an Orgin Live Silver MK II arm for the last 10+ years. The arm is on a gimbal, the table has a hole cut in it for the arm so arm positioning is pretty much fixed. My cartridges have always been mounted somewhat forward in the head shell but plenty of room to move forward or back.

I did not have the VPI arm jig but several others when I first got the new TNT table. I'm using a Benz Ruby 2 and it had to be mounted way back to align (almost all the way). I made a 3-hour round trip yesterday to buy the specific VPI jig for the 10/10.5 arm. I can only assume the dealer sold me the right jig. With the VPI jig the cartridge body is all the way back. This did not seem right.

Please excuse my ignorance as I don't know much at all about the details/specifics/science behind turntable numbers. I can follow directions well. I get the how but not really the reasons behind the why. I started to read up on things like spindle to pivot distance and noticed that there was a set screw attached to what I believe you all call the "dog leg". I loosened it up and sure enough the dog leg moves and it is quite obvious that it moves the pivot in or out. Seems like this is designed to make that adjustable.

A quick google search leads me to believe the correct distance might be 258mm. I pulled off the arm, got a metric tape measure and I am about 240mm from the pivot to the spindle. The pivot/spike is pretty easy to measure from. I'm assuming you measure to the center of the spindle. Is that correct? If not where side of spindle closest to the pivot? I don't have a super accurate metric steel ruler but even with my tape measure I'm guessing this is not right. If I move it back, I'd have to move the cartridge forward so this all seems correct to me.

Can someone please provide me the correct distance from the pivot to the spindle and exactly where to measure. Is there any reason I should not be loosening up that set screw on the dog leg? For now I have the VPI alignment jig set with the original distance because I loosened the screws and had it tight up against the well/spike when I started. So if this is some sort of factory setting I can put the dog leg back to where it was when I got it....does that make sense? However, my gut tells me the arm is not set up correctly. Just so I understand things better what does the distance from the pivot to spindle actually do to the sound? Does it matter down to the mm or is it the case as long as you can get the cartridge aligned with the jig you are good? I'm thinking there are different arm lengths and positions for a reason and if measured in mm that distance matters a lot.

Any chance I have the wrong jig?

Does the queue/lift on these arms always drop like a rock when lowering? Mine feels mechanical like there is no fluid in it for a slow descent.

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rplace
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Re: TNT JMW 10 Set Up Help

Postby tony22 » Sun Jun 30, 2019 7:47 am

258mm is correct, and welcome to the VPI family!
Pass XP-20 & XP-17, AVA 600R, Shahinian speakers, PS Audio DMP & DS, Avenger w/mods, 12" Fatboy gimbal + 2nd mount, Benz LPS, VAS & SS carts, Ortofon Quintet Mono, Logitech Touch, Audience and PSA conditioning, PAD and AZ cables.
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Re: TNT JMW 10 Set Up Help

Postby Brf » Sun Jun 30, 2019 7:56 am

tony22 wrote:258mm is correct, and welcome to the VPI family!


Unfortunately, that is not correct. The P2S distance for a first generation JMW10 is 248mm. Remember, a Generation 1 JMW 10 is a 10” tonearm and not a 10.5” arm like the later generations.
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Re: TNT JMW 10 Set Up Help

Postby rplace » Sun Jun 30, 2019 8:36 am

Where do I measure to/from? Center of spindle? Is loosening set screw and pivoting the dog leg the way to make the adjustment?

I'm more of a user than a technician. Any advice greatly appreciated.

Thanks all!
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Re: TNT JMW 10 Set Up Help

Postby billo » Sun Jun 30, 2019 8:43 am

actually that is not correct either. It's 250 for the first gen arm.
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Re: TNT JMW 10 Set Up Help

Postby tony22 » Sun Jun 30, 2019 8:54 am

Whoops! My apologies to all! Sorry rplace!
Pass XP-20 & XP-17, AVA 600R, Shahinian speakers, PS Audio DMP & DS, Avenger w/mods, 12" Fatboy gimbal + 2nd mount, Benz LPS, VAS & SS carts, Ortofon Quintet Mono, Logitech Touch, Audience and PSA conditioning, PAD and AZ cables.
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Re: TNT JMW 10 Set Up Help

Postby Ducky » Sun Jun 30, 2019 8:54 am

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Re: TNT JMW 10 Set Up Help

Postby rplace » Sun Jun 30, 2019 9:12 am

Can I get a consensus on distance?

How much does this measurement matter?

Can I hurt anything by messing with it?

Thanks a lot!
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Re: TNT JMW 10 Set Up Help

Postby Waxxy » Sun Jun 30, 2019 10:34 am

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Re: TNT JMW 10 Set Up Help

Postby Waxxy » Sun Jun 30, 2019 10:53 am

BTW...the cuing on my older JMWs drops like a rock too. I just feather it down using the cue lever. Can't say I'm not a little jealous watching my buddy's Linn arm drop ever so slowly.
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