2. analog
  3. 123981-46

VPI 3D tonearm adjustment

I have a couple of questions on set up of my new Prime and the 3D tonearm:

1. I've had the TT for about three weeks. I had a scout and moved my Dyna 20x2L to the Prime.
my first impressions was this is a wonderful upgrade. But after a couple weeks I noticed there was more glare on the highs.  I initially set the tonearm parallel to the record - dead level. I then ran across articles about how on some earlier 3D arms the shell warped. I think I have a new style arm, but last night I decided that rather than set the arm parallel I would check and make sure the shell was paralelle - it was not. It tilted downward 1.5 degrees. To get back to paralelle had to turn down the vta adjustment to where the body off the adjustment tower is almost all the way down. But with it adjusted as such the sound is now fantastic. My first question is the shell supposed to be parallel?

2. My second question is now that the tower is almost all the way down I can't use the alighnment jig, the tonearm hits it.  I've heard that the small cup on the underside of the tonearm where the needle sits,can be raised and lowered - is this true for the 3D arm?  There isn't a screw on the top of the arm to adjust with?
last_lemming
melm
1,082 posts
 
The short answer is (1) the head shell should be level when the arm is level and (2) corresponding with the VPI factory about your problem will get you a quicker solution than anything you can do here.

There was another, longer, thread about the 3D arm problem and in it VPI made it very clear that they will take care of it.  Do a search.

Just for the record I have a 12" 3D arm, relatively new and without a problem.  Great arm.
stringreen's avatar
stringreen
6,478 posts
 
Last_lemming....you have the new version.  If there is a problem VPI will send you a new one.
gpgr4blu
1,094 posts
 
Hi Last Lemming:
There is an adjustment to the inverted cup where the needle sits. It is made from the hole at the top of the arm. An allen wrench fits in the hole and lowers or raises the inverted cup which sits on the pin. (Sorry, I don't remember the size). I had the same problem in set up as you and adjusted the height of the rear of the arm (raised slightly) by lowering the cup which will permit the jig to fit. You may have to play with that cup as well as the tower adjustment to get the right arm level while allowing room for the jig to fit. Finally, I have a tapered 3d arm. If I measure a straight line along the top of the arm, it appears like the arm is highest at the pivot point. If I measure along the bottom of the arm, it appears that the pivot point is at the low end. The shell appears to be about level.  In addition, I set my cartridge to be as close as possible to the 92 degree stylus rake angle recommended by Michael Fremer.  
last_lemming OP
639 posts
 
I did try moving the cup. But in my case I need to move the cup up. Doing so effectively drops the azimuth side weights lower and because my VTA tower is almost at the bottom of its adjustment rate it causes the weights to hit the horizontal metal base such that the tonearm can not rotate. 
gpgr4blu
1,094 posts
 
Time for a call to VPI
More to discover