Setting VTA on a new Shelter 901?


I'm trying to dial in a new Shelter 901, knowing I face several dozen hours of break-in before I ought to be too critical.

It's in an SME IV.vi arm on a SOTA Star. The arm has a VTA adjustment dial/rod...but it's not that easy to move, up or downward. Both ways requires loosening some base screws, etc. Not precisely repeatable, either. Nevermind that, my question is...

What's a good "geometry" ballpark to begin VTA tweaking...
cartridge bottom parallel to record? Slightly down at the back? Somebody on Audiogon mentioned slightly down at the front, but that sounds (and looks, in my mind's eye) very scary. But, so far, what do I know?

The cartridge is very, very slightly down in the rear right now, about 1-2° I'd say. Bass seems mostly controlled, but load...treble (strings) are very bright...vocals I'm familiar with seem pretty about right...so far, nothing I'd call warmth. That's some break-up that happens on crescendos...sounds like eggs frying ...seems more like electronic distortion ugliness that mistracking.

Thanks for any help and ideas.

Noel
128x128nnauber
Verybigamp, Thank you for your very informative VTA information. I have also read where it was expressed, you will know when you have the VTA correct when the "image" snaps into focus. This only happens at one point.
I have had problems in the past trying to do this, and am getting a new Table, Arm, and Cartridge from Jay Kaufman at Audio Revelation. This should be a major upgrade for me. Then I can, as you say , stop trying to correct front end problems with my VTA setup. I have always found that if I get the cartridge body parallel with the record surface, I have the VTA at its best for my current rig. My new front end will be a lot better, and I belive, I to will be able to set me VTA better, and get better focus.
I asked Jay Kaufman for his opinion about the 901 being fussy for VTA, He said it was not. Just insure that the cartridge body is parallel with the record surface.
Ron
I respectfully disagree with this imagingability concept of setting VTA. In my experience VTA is correct when surface noise is reproduced in a different plane than the music on the disc. If the noise is within the fabric of the music then you ain't there.
I gotta respectfully agree with Viridian on this one. I would have repsonded sooner but I have been caught up in trying to find micro-thin playing cards or, alternatively, modifications to my VTA adjuster that will allow such minute changes to be effectively realized.

Seriously, though, I don't know that you can ever get all surfacce noise to an otherwise inaudiable level (but one could hope). There does seem to be a magic point at which everything "clicks" or, rather, doesn't click, as it were.
Viridian, I do not think you disagree with the “imagingability concept” but rather you’re trying to expand the said. Yes, at the correct VTA setting the surface noise become the orders of magnitude less annoying but this it not a reason but a consequence of something else. When “imaging” (as a correct PATTERN of phase randomonization) kicks in; when the X-force (I intentionally left without explanation what it is) embraces the musical messages and opens a communicative bridge between a musical event and a reproduced Reality; and when some other parameters of sound reproduction are set “correctly” then a specific mechanism get activated that tune a listener’s consciousness out of the external irritators and make the surface noise “reproduced in a different plane”. So, a minimization of noise is a process that flows out of something else. Besides, there are many other ingredients that affect a perception of a surface noise… There are some phonostages (assumedly they all have equalized input R and C) that make a cartridge to reach the best imagingability (Please, remember I said that “imaging” was VERY loaded word) and a less-annoying “plane” of surface noise at the different points/heights (there are some mechanism how a noise reduction could be done inappropriately-electronically) However, there is no free lunch and along with noise reduction those phonostages fuck up something else musically. I have seen those examples again and again…. So, what I propose is that the noise flipping in a different “plane” is one of the properties of the “Correct VTA” but this is not NECESSARY THE SIGN that a cartridge is in the correct VTA point.
Thanks for all your tips and comments.
I'm still breaking-in...just reached the 20 hour mark on my Shelter 901. But I have found a really sweet spot in my slowly increasing VTA adjustments. Having started at about 1.5° down at the rear, and adjusting my SME IV.vi in 1/8-clockwise increments, I'm now just a tiny hair from dead flat (cartridge bottom relative to record surface)...with probably a bit more to gain in treble smoothness.
But I think I'll wait till the 50-hr. mark before further "+" VTA tweaks.
Cheers, all.