Time to choose: Baerwald, Lofgren, Stevenson ?

Hi Raul,

I agree with you that a tonearm manufacturer should provide an alignment tool with their product. It’s in their best interest that the customer have the best chance of achieving a good setup.

Lew -

An arc protractor can get you to within .001" of tracing the arc - limited only by your patience. I had forgotten about Conrad’s site. I’ve never tested it against the ones I produce with my CAD software.

As noted above, an arc protractor is specific to a single tonearm effective length, and you now have a website that will generate a protractor for you. If your printer takes card stock paper, you’re all set.

I stopped following the "other" protractor thread when the manufacturer refused to reveal his chosen alignment. It’s his choice and I respect that, but at the same time it leaves me no way of validating the accuracy and REPEATABILITY of adjustments made using his tool.

Parenthetically, I might add that I’ve seen some very good setups done with a Feickert. My preference for an arc protractor is that it eliminates any and all ambiguity.

If you think about any tool which depends on your siting down your cantilever at one or two spots, you’ll realize that the manner in which an arc protractor magnifies pivot-spindle/overhang errors lends a dramatically higher level of precision and it does matter.

For sake of argument, let's assume you have a 0.5mm overhang error in your setup.  If you rotated your arc protractor so that you can land the stylus on the inner (lead out) side of the arc, and and (without rotating the protractor) you swing the arm over the lead-in (outer) side of the arc the stylus will be several mm from the arc. 

This is can be confusing when someone is first learning how to use an arc protractor because they think they may have a 2, 3, or 4 mm overhang error.  Once you understand this "error magnification" however, it is a huge benefit in terms of enabling precision adjustments.

If forced to choose, I would opt for getting one tonearm/cart set up perfectly rather than taking a buckshot approach of multiple tonearms with suboptimal tools. Yes, I appreciate the fun of playing with multiple arms, but I’m a patient guy and would rather get one thing right than many things wrong.

Cheers,
Thom @ Galibier Design

Thom,  I am not sure what is your point in the last 3 paragraphs above, except to say that any protractor can give bad results if you don't know how to use it.  And I don't think any one of us takes a "buckshot approach" deliberately.  I am sure each of us is very meticulous, or at least feels that he has been as careful and precise as eyesight and lighting and the protractor make possible.

Wouldn't it be nice if we found out that underhung tonearms, which demand nowhere near the precision accorded to mounting overhung tonearms, were to become accepted as the superior sounding option?

@fleib

Chakster,

I bet you’ll wind up with Loefgren alignment. Both nulls are within the recorded part of a 7". Error will be much less through most of song. Stevenson will be better at the end, but much worse up until there.

No, only one null point is on the recorded part of the 7" inch. As you know Feickert use 3 steps: 1) for overhang. 2) for offset at outer null point. 3) for offset at inner null point.

Only Stevenson’s geometry is withing the 7" inch two times: First at step-1 (aka overhang), which is exactly the beggining of the recorded grooves (aka the beggining of the track, not the edge of the vinyl) on 7" inch, and step-3 (aka offset) on the inner null point which is exactly in the end of recorded music (not the edge of the label) on 7" inch vinyl. While the Baerwald and Lofgren are on the 7" inch ONLY at inner null point once.

I have a Smartractor for a few days now and settle the Uni Din with good results. Today I changed the curve and trief the Loefgren B (DIN) and I clearly prefer the latter.
I listen mainly classical music and I find the flow of music more natural to my ears. Also the micro dynamics' the way the note begins has more snap.
tt is TW Acustic Raven AC wih Da Vinci arm and MC Anna cart.