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Cartridge alignment, WallyTractor, SmartTractor, oscilloscope and Analogmaigk.

I am building my new system in my second home in the US which I use only when I go to the US to work, and I will not have the benefit of having my partner and analog guru with me when I set up my table there. 

To be clear she much rather have a new cartridge, tonearm, table or phono amp than nice jewelry, shoes or dresses, and 2 of the best hifi stores in the area are always asking for her opinion and sometimes to set up tables. 
Until now, all I had to do was to put my record on the table of her choice, and enjoy the music. 

 During our dinner with her, we were discussing,  what should I be doing and what tools to bring with me. I am an a mathematician  and work with electrical engineers so I understand numbers so I like the idea of an oscilloscope and Analogmagik and I have done quite a few setups with the WallyTractor before I met her, but she swears by the SmartTractor and claims that the SmartTractor is more accurate, simpler and flexible.

My question then is, what is your opinion on the 2 protractors?
Please do  not add another different one, I am not going to buy another one. :) 

In her opinion the  UNI  alignment is superior to the new record in the Wally, and since pivot to spindle is never identical, the SmartTractor does a better job as it actually takes into account for those imperfections/discrepancies in the spindle to pivot distances, while the Wally does not. 

If I am going to face the firing squad, I want to have some good different concepts.

I apologize for my English, until a few months ago I never discussed Hifi in English. 


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Showing 4 responses by larryi

larryi
3,757 posts
 

If one can find the tonearm pivot point with extreme precision, then the Smartractor or Feickert are the way to go.  I like the Smartractor a lot.  It is built for extreme precision, including offering different diameter spindle inserts so that there is absolutely no slop when placing it over the record spindle.  The lines and point where the needle hits the mark are very clear.

 

larryi
3,757 posts
 
I own both.  If you can accurately located the center of the arm pivot, the Smartractor is much easier to use.  This is the case because you do not have to move the arm to many different locations and find the precise point of contact multiple times.  The Wallytractor affords one more ways to confirm the correct settting so I suspect that it is more accurate.  
I don’t think that extreme accuracy makes sense to try to achieve when manufacturing tolerances in setting styli is so poor that the zenith can be off by several degrees.  The only way to know about how far off is your cartridge is to have it examined by a service like Wallytool, which also has a way to compensate for small zenith error (a protractor that provides for a way to deliberately set the cantilever at angle away from perfect tangency to compensate for zenith error).

My answer is: If you can locate the pivot point, and you find it difficult to see the precise point of contact such that making a single observation is a big plus, go with the Smartractor.  If your eyes are up to it and you have the patience, the Wallytractor offers more confidence in the setting.

Something like the Mint protractor should also be considered; it is quite easy to use and is supposedly very accurate.  The only downside is that it is bespoke (made to order for your particular arm and spindle-to-pivot distance) so it cannot be used for other set ups.
larryi
3,757 posts
 

With the Walltractor, you first measure the pivot to spindle distance with the supplied tool to find the closest matching curve that establishes the overhang.  There are a fixed number of curves for the pivot to spindle distances measured, so your actual distance might not be a precise match.  That is a potential source of error, the overhang may not be a precise match.  Once you have that distance, you tighten one screw of the two that hold the cartridge so that the cartridge is free to pivot around the fixed screw for you to change the angle of the cartridge to assure that the cantilever is correctly aligned.  When the cantilever is correctly aligned at the two null points, you have a quite precise alignment, even if the overhang started out as a somewhat rough approximation.

The potential source of error with the Smartractor has to do with precisely aligning the whole gauge to the pivot point--if the pointer is not precisely over the center of the pivot, the lines on the gauge will be slightly off.  Again, the amount of error should be pretty low if you get the needle quite close to the pivot point. 

Both protractors are more than good enough, particularly when you consider that the ideal alignment involves angling the cartridge to make sure that the zenith is correct, and none of these tools do that.  Wallytools has a service for that which also analyzes the cartridge for other parameters, including the dynamic SRA (the actual angle of the stylus when it is playing a moving record).  The analysis requires extremely expensive microscopes and know how, so no consumer can do this for themselves.  

 

larryi
3,757 posts
 

I think that even with a good scope it is a lot of trouble to measure SRA.  Dynamic SRA measurement is, however, only a little bit more difficult--it just requires the record to be spinning (spun by hand, any speed) when the image is captured.  The surface must be a record, not something else like a CD, so, one must take a sacrificial disk and shave off the edge bead.  Personally, I don't bother with SRA measurement--I set the arm close to parallel, then I listen when making small adjustments away from parallel.

The Wallytool service that is much more useful is zenith measurement. This is a subject that is not discussed much because few can make the measurement, even very expensive cartridges can measure poorly, and aside from small errors, there are no means to correct the manufacturing defect.  For all the effort one puts into aligning the cantilever to be pointing in the correct direction within one degree, it is a bit disheartening to know that the stylus surface cuts may be misaligned by ten degrees or more.  If I recall correctly, Wallytools has a means for correcting for errors up to three degrees, based on this analysis.

It is quite the wonder that analogue playback dounds so good with all of the technical shortcomings and compromises.

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