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How critical is alignment error??

I would appreciate advice regarding the following issue.

A tech recently installed a new tone arm on my old turntable base. The new arm has a spindle to pivot (S-P) distance of 222 MM. Upon return of the TT with the new arm, I noticed that the S-P distance was about 5 MM short, say 217 MM. I own a protractor and checked alignment. As I suspected, the cartridge overhang was about 3-4 MM over the sweet spot indicated on the protractor. BTW, I was able to move the cartridge back in the arm shell towards the pivot point, but even with the maximum adjustment, as stated, I was still off 3-4 MM.

My question is how much distortion will this error introduce in the playback? Ordinarily, I would ship the TT right back to the tech for adjustment, but I am reluctant to do so because of the possibility of damage from shipment. Further, I suspect that the fix will entail cutting out a part of the undercarriage in order to accomodate the larger arm and I suspect the tech will argue. The old arm had a S-P distance of 215 MM. If the error is signifant, I will have to reconsider what may next steps will be.

Thanks for your advice.
bifwynne
syntax's avatar
syntax
2,193 posts
 
That error is not subtle. It is in analog terms not in the wrong street of town, it is like being on the other side of the world.
swampwalker's avatar
swampwalker
5,138 posts
 
That error is not subtle.
I agree. And if you sent him instructions showing how to do the work, its hard to understand why he did not. I agree w Elizabeth that the place to start is w an inquiry, not an agruement (it may end up there, but you gotta try to resolve it in a friendly manner). Good luck.
dgad
782 posts
 
The error might not even be for the worse. Go to the vinyl engine website & enter the overhanf #s etc & calculate the distortion. I know I will get it on this site but HTA is not as important as VTA & Azimuth unless grossly off. But use VE calculations to confirm. The distortion figures should be easy to come up with. Remeber many arms might natively have higher distortion than some longer arms. One caveat 222 is a fairly short effective length. But sometimes longer can be better.
rodman99999
6,160 posts
 
Plugging his overhang figure into a formula will be worthless at this point, without the ability to correct the figures for the error in his spindle to tonearm pivot distance. VE's formulas(like ANY given alignment protractor) assume a correct spindle to pivot distance for the tonearm's length. The existing error throws off the whole geometry of the process(and geometry is EVERYTHING, regarding tonearm/cartridge alignment).
dgad
782 posts
 
Rodman,

Yes but he can plug in the deviation and check the change in distortion. He can even print a new protractor to compensate. A lot can be done. Remember effective length is a design element with a nominal figure. Take a look at an SME where there is no nominal length but an exact length but yet pivot to spindle distance can be changed and that is all. The headshell if fixed for all parameters for the most part. If you are lucky a poor setting can end up being the correct setting. Just like some arms can be setup w. Lofgren A or B.
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