Setup Procedure

Disclaimer:

There are many opinions on cartridge alignment, and disagreement is common, even among experts. The setup procedure and the parameters outlined here have been studied and tested by Durand Tonearms and Found Music. 


Attention to fine details with a proper protractor is paramount to getting good alignment results. A mirrored protractor made especially for the tonearm geometry in question is my current preference. It should allow the user to align offset angle and azimuth at a minimum of two points along a proscribed arc. 




In broad terms

deviation of the cartridge stylus from "alignment" in any axis results in audible distortion due to extraneous forces being exerted on the cartridge mechanism. The better the alignment, the freer the cartridge is to trace the groove properly. This provides better signal where it matters: at the source.


There are seven parameters that we have access to in tonearm/cartridge setup. They are all directly responsible for sound quality and are interactive and interdependent to some degree:


-pivot to spindle distance (P-S)

-vertical tracking force (VTF)

-effective length (overhang)

-offset angle (zenith),

-azimuth (vertical orientation of stylus when viewed from front), 

-vertical tracking angle (VTA) or stylus rake angle (SRA) 

-anti-skate 


Again, these parameters rely on one another. If one parameter is adjusted far off the mark, it can take others out of tolerance with it. It is usually necessary to go through a setup procedure more than once in order to get it right.





 The phonograph cartridge

is designed to function:



 - with stylus (and cantilever) pulled through the record groove normal to the groove centerline (when viewed from the front of the cartridge)

-  with stylus tip raked slightly toward the incoming vinyl

-  within a manufacturer's recommended tracking force range



 The purpose of alignment is to provide the cartridge an environment where the above criteria are met on the play surface of the record. Note that even in an ideal condition, this requirement is not quite met on pivoted arm designs except at two carefully chosen null points; the locations of which are specified by alignment type (Lofgren A, B, etc.). See link to diagram below where you can see examples of deviations from the null points. 

In the .pdf drawing below (link), the null points are the two locations on the arc where the stylus follows a line exactly tangent to the record groove. There are three other points on the drawing where you can see that the direction of the stylus deviates from the tangent, and these are marked with their deviation from tangent in degrees.

In practice, this deviation is much less significant than setup errors.



The procedure:


1) Set pivot to spindle distance

All tonearm geometry rests on an accurately set pivot to spindle distance. This must be set accurately first and foremost. P-S refers to the distance between the rotational center of the tonearm's bearing (the pivot) and the rotational center of the turntable's platter (the spindle). If the P-S distance is not set correctly for your tonearm, the tonearm will not describe an arc on the play surface of the record that permits zenith (offset angle) to agree at both null points. 

If you must use a ruler to measure P-S, it is helpful to place a mirror on the platter as a visual aid to ensure the ruler is viewed normal to the platter surface.




2) Set VTF, VTA starting points

- Attach cartridge to the headshell, snug screws, connect tonearm leads to cartridge pins.

- Confirm that antiskate is disconnected or set to minimum.

- Confirm that turntable platter is level.

- Set tracking force to the middle of manufacturer's recommendation using a scale made specifically for this measurement. Avoid setting the stylus down when the weight of the system is unknown! To be safe, you can start at zero balance and progressively increase tracking force to the desired value.

- Set VTA to a reasonable setting. The armwand sitting horizontal with the stylus in play position is a reasonable starting point. 




3) Set effective length (overhang)

using the ends of the arc on your protractor. Make sure you have plenty of light to see your work. Use a ~10X loupe so you have a good view of the stylus as it rests on the protractor. Place the loupe to the side of the cartridge such that viewing of the stylus is in line with the arc.  If your protractor has no arc to trace, there should be crosshairs at the the null points that will facilitate this measurement. Effective length is set by slightly loosening the mounting screws and moving the cartridge fore or aft in the headshell until the stylus tip rests on the curved line (or crosshairs) at every point when cued down. It is helpful to leave the headshell screws just snug enough so that movement of the cartridge is permitted without having to loosen and tighten the headshell fasteners repeatedly. See example below with 10X loupe and LED flashlight for backlighting:


4) Set offset angle (zenith)

by rotating the cartridge in the headshell with set screw(s) slightly snug from step #3. Slightly less magnification, ~4X, is useful for its wider field of view in this step where you will view the stylus and cantilever from the front of the cartridge. Offset angle is set by aligning the cantilever as perfectly as possible with the parallel lines on the protractor. The pics below show wrong, wrong, and correct as you scroll down. Note that rotating the cartridge for this step can be difficult to do without disturbing the effective length from step #3. 



Wrong - cantilever angles toward the left.
Wrong - cantilever angles toward the right.
Correct - cantilever is centered and aligned with protractor marks. Note the visual aid rendered by the reflection of the marks on the mirrored surface and the reflection of the cantilever with respect to them. This is going to sound good...

Once you have checked and are satisfied that effective length from step #3 and offset angle from step #4 are both set correctly, tighten the cartridge in the headshell. The torque required is "finger tight" - on the order of inch-pounds.


Here we can check if our pivot to spindle distance is correct with the 2 point arc protractor. If the cartridge's cantilever will not align equally on both null points, this is a red flag that P-S is not set correctly. Small errors in P-S can make a surprisingly large effect.



5) Set azimuth

Easier said than done, right? This adjustment is important, but varies on high end tonearms from none at all to adjustment on the fly. Most arms fall somewhere in between with a mechanical adjustment that must be made with the arm out of the play position. 

Azimuth adjustment involves an axial rotation of the arm wand that is used to align the stylus symmetrically to the record groove. When approaching the correct setting, this can be heard in high resolution systems as a slight increase in volume, clarity, and harmonic content. Detrimental effects on imaging and channel balance come into play as azimuth approaches gross misalignment.


Ideally, there are no errors in our setting of offset angle or in the cartridge's construction geometry, and we can leave our azimuth adjustment to its theoretical duty of placing the stylus perpendicular to the groove. Sadly, life isn't always so simple and there can be small errors that we want to account for.  

 Subjectively, we find that azimuth adjustment can help compensate for small errors in the offset angle. The two parameters are in two separate planes, and are thought of separately, but in practice the two adjustments can and do have some effect on each other. 

If azimuth adjustment has profound effects on imaging and the sense of space heard in playback, this can be a hint that the offset angle is off and should be checked again. 


Azimuth is dependent on stylus profile. Some require extreme precision, while others are more forgiving. Don't be afraid to experiment!




6) Before play,

check tracking force again. Movement of the cartridge in setting of effective length in step #3 will affect VTF. It is now a good time to set it as precisely as you can. This is a parameter that is worth experimenting with within the manufacturer's suggested range. In some cases, acceptable results can be obtained slightly outside of this range, but this is not the norm and generally NOT where highest performance is realized. Heavy VTF tends to make the sound more damped and kills nuance, lighter VTF makes the sound thinner and "quicker" to the limit of mistracking. Listen for tonal color, weight, dynamic control, and tracking during loud passages to set VTF.



 

7) Set VTA
This parameter involves raising or lowering the pivot of the tonearm to affect a change in the stylus rake angle (SRA). The stylus rake angle is the included angle between the vertical center line of the stylus (when viewed from the side) and the horizontal plane of the record play surface. It pays to experiment with this parameter, as it does make a profound difference in tonality and focus. To adjust this by ear, listen to the bass registers for greatest attack and weight combined. You may want to spend time listening to too far up and too far down in the adjustment to get a feel for where "best" is for your cartridge. Note that adjustment of more than a few millimeters from the VTA setting you start with can alter effective length. Theoretically, VTA should be adjustable over a wide range without measurable geometry changes, but this is not always the case in practice due to machining tolerances, tonearm design, turntable orthogonality, and other factors.

Side note: Changes you make in tracking force will slightly change VTA. More tracking force has the effect of lowering VTA due to increased suspension sag, less tracking force will effectively raise it. 

Keep in mind that VTA and VTF are mechanical adjustments that bring the stylus, cantilever, and suspension into ideal operating conditions as a system. Think of VTA/VTF not as tone controls, but as parameters adjusted to honor most proper contact of the stylus contour with the groove.



8) Set Anti-Skate
Anti skate force is available on most tonearms to counter the tendency of stylus drag to pull the arm toward the spindle during play. Anti skate force is a "best  compromise" adjustment that is set to achieve best tonal and channel balance once other parameters are set. Again, don't be afraid to experiment.



9) HAVE FUN!