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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. 


astolfor
larryi
4,275 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.
rdk777's avatar
rdk777
580 posts
 
Another vote for the SmarTractor and the Uni-Din alignment.  
mijostyn's avatar
mijostyn
8,570 posts
 
I bought the SmarTractor. It is a more finely made device than the others with an excellent magnifier.  It gives you all the major alignments and once you are used to it is a breeze to use.

I politely disagree with your guru. I use Lofgren B and here is the logic. It gives you the least average tracking error from the edge of the record down to 75 mm. Perhaps one in ten records continues in closer than 75 mm. People will say "but, that is where the crescendos are."  How many records do we play that actually have crescendos in closer than 75 mm.
I will venture to say very few. Get a 6" millimeter rule and measure every record you play for a month and tally the score. 

Both Marc Gomez and Michael Fremer I believe are also now using Lofgren B.  

To be perfectly honest I can not hear a difference between Lofgren A or B and have not tried Uni Din at all.
astolfor's avatar
astolfor OP
317 posts
 
@mijostyn, you are right. In our house we have 4 tables with 2-3 arms each... please don't make fun :) so we have different alignments. 
In my house in the USA I only have one table, and 2 tonearms. 
And I am thinking of UniDin in one arm and Lofgren A or B in the other.

My question about the protractors is more about how the 2 go about implementing the null points. 

It is my understanding, that the Wally derives the null points based on the assumption that the spindle to pivot distance in the turntable is perfectly matched to theirs, while the SmartTractor derives the null point based on the actual  spindle to pivot measurement.
Is my understanding correct? 
If so isn't Wally's assumption a big one?
If the spindle to pivot is off by 1mm then would it not be the case that the tangential traces in the Wally are off?

I love the Wally, so I am trying to understand and not say one product is better than the other.


larryi
4,275 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.  

 

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