VPI Classic 3 + 3D Tonearm SRA Adjustment issue


I have owned a VPI Classic 3 for about 4 months now. The VPI folks kindly installed a Dynavector 20X2-L that I provided. Initially I followed the manual's setup instructions: VTF, VTA by making the arm parallel to the record, and azimuth by the rod method. Michael Fremer suggests this method leads to 80% precision. The table sounded better than out of the box and I was happy.

But who buys an $8,500.00 turntable setup to be lastingly happy with 80% setup precision?

So after reading enough and obtaining the tools I set out this weekend determined to extract another 15-17% out of this system. The "tools" are a 2-digit-precision digital VTF gauge, a 400X digital microscope, and a Fozgometer Azimuth Meter.

Confirming the VTF was within range for this cart (1.8 - 2.2g) I set out to correct the SRA via microscope pictures as described by Michael Fremer and this is where trouble began as I could only adjust SRA to ~91-92 degrees by raising the arm as far as the VTA tower will go without loosing thread. At this height, a second guiding post the tonearm base has located near the arm rest no longer reaches completely through the top platform of the tonearm and it can't be locked via the locking screw next to it.

This seems odd, but I re-measured several times being very careful when taking the images to be parallel to the cantilever. Playing music like this confirms the tonal balance sounds better.

I was able to adjust the azimuth and the rest. But it seems wrong that the arm be that high to achieve proper SRA.

Could it be the cartridge cantilever is angled wrong? Could the VTF affect the SRA enough to cause this if it was on the higher end of the range? Or is there a way to raise the whole tonearm not using the VTA tower to achieve a more appropriate base height that then can be fine tuned with the VTA tower?

I appreciate all insights.
128x128isaacrivera

Showing 4 responses by isaacrivera

Hi Hiendmuse, thanks for your thoughts. I had the arm parallel for 4 months. The resulting high tail from the microscopic adjustment actually sounds much better in this system. I have some old 6-eye Columbia records that always sounded out of register and I though that's how mid-50's Columbia records sounded. Violins in particular sounded high-pitched and textureless. Boy was I wrong! Not only do they sound in good pitch and nuanced. There's a whole orchestra of properly-pitched instruments too! Bass has gained weight and depth. They problem with trying to set SRA via VTA is that it assumes everything in between is just perfect. The arm has no variation and the cartridge is perfect. Microscopy bypasses those potential areas of variation. In the end the adjustment changed a good 15mm upwards. An SRA setting change that big can't be adjusted by ear. The farther you are from the "correct" spot, the less meaningful small changes sound. But from one degree off to the "correct" spot, the change is dramatic. So a 15mm difference is almost impossible to get to by ear if you change a few mm at a time you won't hear a difference.
Thanks Dougdeacon, the VTF methodology you describe sounds appropriate for figuring the cartridge's actual range. And VTF seems like the base upon which all other settings are built on. So I will go back to the drawing board next weekend. I may also get a more accurate scale. Mine is the one supplied by VPI and, though it does not change when I approach the cart to the scale, I sometimes have to weigh several times and use the most repeated value, there is variation.
Thanks Brf, Stringreen...

Stringreen, I have read your thread on the 10in 3D arm and it appears that the issues got resolved around last month by VPI. I got my arm back in May. You can see a pic of it here ( http://www.vinylengine.com/turntable_forum/download/file.php?id=9493&mode=view ).

Does this look like the right combo to you? I am wondering if I need a heavier counterweight to move it closer to the bearing and also whether I got the right kind of counterweight at all, because mine is hard to do fine adjustments with. It feels like the thing is lined with rubber inside it resists sliding on the arm tail a lot.
Ok. It was good timing that VPI just started a support forum on their own website last week. I posted the issue there and they responded quickly. It turns out VPI's unipivot arms' female bearing socket height can be adjusted with a hex wrench. It adjusts quite a bit. I had to play with this some because if raised too much this way the arm's lift will not reach the tonearm pipe anymore, rendering it useless. However I was able to reach a good overall compromise position that did allow to set the SRA at my desired angle and lock the platform in place to the guiding post--and operate the lift. Thanks to all who helped.