2. analog
  3. 1144172162

VPI Scoutmaster - Anti-skate again..

Hi,
I'm sure this has been covered, but I couldn't find it...

As we all know, the coiled wire of the JMW-9 tonearm provides anti-skate force naturally, and is seen by VPI as preferable to any mechanical implementation.

VPI now provides a mechanical anti-skate with the Scoutmaster turntable. It is supplied but not installed. VPI still stands by their original position on anti-skate.

Now, for my experience.

I started without the use of the mechanical anti-skate. Listening, backed up by the Hi-fi+ test LP, convinced me that more anti-skating force was needed. I twisted the lemo connector counter-clockwise to apply more force, but I didn't notice any difference.

I then implemented the mechanical anti-skate. I found by visual inspection and confirmed with the test LP that, even at the lowest setting, far too much anti-skating force was now being applied.

Listening tests with the mechanical anti-skate engaged were a mixed bag. I found the image to be more centered, rather than leaning to the right, but I also noticed a loss of fine detail. For instance, when a fast sequence of plucked guitar notes were played, each note stood out more independently WITHOUT the mechanical anti-skate. With the anti-skate engaged the notes smear together slightly.

Has anyone had a similar experience? I am hoping to find a solution that will enable me to focus the image better and not lose any detail. It seems to me that I need a way to provide a little more anti-skate, but not a lot more. (and I am slightly baffled as to why the lemo twist method seemed to have no effect whatsoever.)

Cheers.

Tom
tfkaudio
dodgealum's avatar
dodgealum
1,404 posts
 
The mechanical anti-skate has a thin piece of fishing line that attaches to arm opposite the one with the weight at the base. This arm has about five spaced indents meant to catch the fishing line so you can adjust the amount of anti-skate force being exerted. On my setup the fishing line is on the middle indent therefore providing about 50% of the amount of anti-skate available. Hope this makes sense.
dougdeacon
3,338 posts
 
I don't have a JMW, but Tfkaudio's description of sonic murkiness with VPI's new AS device exactly mirrors what we hear if we set AS too high on our rig. Excess lateral pressure from the arm inhibits free movement in the cantilever/coil relationship, which dulls dynamics.

The solution is less AS, though how you'd implement that on a JMW is beyond me. Is there some way to put a lighter weight on the string or change the position of the fulcrum?

P.S. If you're using HFN&RR side 1/tracks 6-9 to set AS, don't just increase AS until you "pass" the highest track possible. That will result in AS being too high for real music. Skating force varies as the arm traverses the record, so using one (unrealistically dynamic) track located on the innermost grooves will skew your results.

A better way to set AS with that record is to equalize buzzing on the three widely-spaced "tracking test" tracks on side 2. This method achieves a reasonable compromise AS setting across the entire record.

The best way to set AS is to throw the HFN&RR record away. Do what Tfkaudio is doing: listen to music and adjust to maximize channel balance and center imaging while minimizing murkiness.
tfkaudio OP
591 posts
 
Dodgealum,

The 5 spaced indents don't influence anti-skate force. The weight on the other leg does. The fishing line should be connected to the indentation that makes the fishing line parallel to the table when the arm is in the armrest. You then slide the weight on the other leg of the AS device outward from the pivot point to increase anti-skate force. The weight on mine is all the way against the pivot, so I cannot decrease it any more.
tfkaudio OP
591 posts
 
Sberger,
I've found setting the azimuth to be a challenge. What I notice is that, using the "coffee stirrer" method, I can get the stirrer parallel to the table, but when the stylus sets down on the record, it tips slightly away from the center. So I adjusted it so that the stirrer tips slightly toward center and evens out when it makes contact with the record.
Did you have the same experience?

Cheers.

Tom
dodgealum's avatar
dodgealum
1,404 posts
 
Tfkaudio. Interesting. Either we have different anti-skate rigs or one of us is wrong. First, the weight on mine does not slide along the post--it is fixed in position closest to the fulcrum. It is immovable. If it did move the amount of anti-skate added or subtracted by moving the weight would be extreme indeed. This is why you move the fishing line on the other post--it provides a much finer adjustment. If you are somehow moving the weight along the horizontal post you are adding (or subtracting) significant weight and this, I would offer, is why your sound is getting screwed up. Second, I do not understand your description of how to position the string. You say position it so that it is parallel to the table when the arm is in the rest. Given where it mounts this is going to be exactly the same for each and every table. Why make it adjustable at all if it serves no purpose other than to be parallel to the table?

I'm of the opinion that you use the position of the string to adjust the anti-skate and that the weight remains fixed in position. I could be wrong here but what you suggest doesn't make sense to me. I even went over to my table to try to pull the weight toward the outer end of the post--it won't move.

I'd really be interested in hearing from others or, better yet, Mike from VPI on this one.
More to discover