Reminded once again of VTA criticality...

Curio, I agree with your comments. Do you own both?

By coincidence earlier today I was double-checking VTA with the micropoise and noted that even a 0.3mm ht adjustment produced a noticeable offset on the bubble. (I noted the setting on the calibration first so that I could get back to my ideal level.)
One thing I've also observed is the tension of the locking screw can adversely affect the smoothness of the sound. For serious comparisons I'd be inclined to make sure it's always tight (but not "Linn tight" where some Dealers have braced their foot against the wall when turning the Allen key but 2 finger tight plus 1 or 2 degrees of turn - which is still within Bob's guidelines)
Feedback from other Phantom users appreciated... :)
Cheers........M.

Tobes :
"Moonglum that depends on the arm being used.
My old Graham 1.5T, which had stable balance (weight slung below the pivot) like most unipivots, used to vary VTF by a similar amount - maybe more.
With the Phantom arm, which has neutral balance, VTF isn't much effected by VTA changes."

Useful info - thanks Tobes. I previously used a Linn arm (dynamically balanced, loaded by spring downforce) and for years laboured under the misconception that it was totally unaffected by VTA change.
I try to be more sensible now... :) ;)

About the perfect flat VTA I have found the Reed 3Q arm and the Graham Phantom MKII fantastic to help user to find the best starting point with every cartridge.
The first with the "laser beam" and the second with "bubble micropoise level".
But also these are only perfect starting points.. unless you are sure to have a cartridge who's made to give its best flat 0 on the LP.

Here the laser beam in action:

http://img821.imageshack.us/img821/8811/laserh.jpg

01-07-11: Moonglum
Mike, the burning question is : are the changes the result of minor VTA or the change in SRA resulting from VTF? I recall someone did measurement on this and they estimated +/-3mm = +/-0.1g...

Moonglum that depends on the arm being used.
My old Graham 1.5T, which had stable balance (weight slung below the pivot) like most unipivots, used to vary VTF by a similar amount - maybe more.
With the Phantom arm, which has neutral balance, VTF isn't much effected by VTA changes.

Mike, the burning question is : are the changes the result of minor VTA or the change in SRA resulting from VTF? I recall someone did measurement on this and they estimated +/-3mm = +/-0.1g while I also remember a Stereophile contributor writing that it was 5mm = 1g (!!)

(That's GOT to be wrong otherwise all of our suspensions would be knackered by now???? :)

I agree. The acceptable range is narrow - especially for line contact styli. Little changes make a big difference in making the sound sound musical.

Fatparrot, my tonearm doesn't allow adjustments "on the fly." It is totally locked and rigid during play. To adjust VTA, I have to lift the stylus; loosen a set screw, adjust two nurled rings that raise and lower the arm in very small increments, then re-tighten. With practice, this process now takes me 10-15 seconds to accomplish.

For many years I used an Eminent Technology arm that could be set to allow adjustment on the fly. What I found, though, was that leaving the couplings just loose enough to allow for adjusting on the fly also compromised the bass response of the tonearm. So, I stopped leaving it that way and tightened it down playback for improved sound quality. There are other tonearms that may permit VTA adjustment on the fly without compromising the sound quality, I just couldn't name them. For me, I just draw the line that any tonearm I own must allow for VTA adjustments with relative ease.

What I hear with VTA adjustments is exactly what Lloyd Walker describes in his article on "Fine Tuning Your Turntable" noted in my earlier post in this thread:

General Rules and Effects:
VTA:
~ Raise the VTA (raise the rear of the arm) and the highs will usually get better. Too much and you will lose the bass.
~ Lower the VTA and the bass will get stronger. Too much and you will lose the highs.

There is also an overall focus and coherence that will snap into place when VTA is right on the money. If the overall acoustic sounds a bit veiled, often raising the VTA just slightly, will bring an improved transparency that is not just an increase in high frequencies.

The sensivity of one's system to the effects of VTA adjustments are very much cartridge-dependent; some cartridges are a lot more sensitive to minor changes in VTA than others due to the contour of the stylus. And the degree to which you will hear changes is also somewhat dependent on how resolving your system is.

Hope this helps!
.

Rushton, does your turntable allow adjusting VTA "on the fly"? What were the actual sonic differences did you hear after adjusting your VTA?

Good link, Bigkidz. Another good article on VTA and turntable setup is the guidance Lloyd Walker posts at his web site:

http://www.walkeraudio.com/fine_tuning_your_turntable.htm
.

Thanks to you both. This is helpful to all of us.

Funny just saw this.

http://www.enjoythemusic.com/magazine/equipment/0700/cartridgevta.htm

Happy Listening