Arc Style Alignment Protractors

[galibier_numero_un]

All,

I've begun producing arc-style alignment protractors (Baerwaald for now), and will be sending dedicated protractors made of card-stock for all tonearms shipped from Galibier from this point onward. Of course, Ralph will provide these same protractors for all Artisan Arms shipped from the UK as well.

Existing customers can contact me for protractors for their tonearms.

The level of increased setup accuracy is significant, and experienced as decreased distortion - a level of precision greater than any two-point protractor can provide irrespective of materials (e.g. mirror backed acrylic).

I updated my FAQs page to reflect this thinking.

http://www.galibierdesign.com/faqs.html#setup_proc

In that section, I have link to an analysis I performed on fixed position headshell mounts like the Schroeder and SME. We can make protractors for these arms which are dependent on the cartridge in use as explained in both the above FAQ as well as the analysis.

Cheers,
Thom

[dmailer]

Thom, I thought my tonearm was setup properly based on using several of the two point protractors that I have had. When I received your arc style protractor for the Schroeder I was not prepared for the enormous improvement I experienced. It seems that the previous alignment was off a fair amount although with my eyes it seemed right on using my other protractors. This one is much easier to get accurately. The turntable, arm, and cartridge I have are very good and obviously can sound very good even when not set up just right. I kept tinkering with azimuth, tracking force, damping etc to try to improve my sound but nothing prepared me for the sound improvement by just getting the cartridge adjusted properly to hit the arc. There is a wholeness to the music. Musical notes have noticeably better sustain. After a few records I found myself not listening for the audiophile things but just enjoying the music which sounds more natural now than ever before. Thanks for sending this out it has been a revelation in my system.

[galibier_numero_un]

Thanks for the feedback Larry.

As I mentioned to you (with regard to Schroeders), I'm wrestling with whether to produce a protractor for each dedicated size (e.g. 239 mm eff. length) which contains multiple arcs - to allow for different cantilever lengths which will change the effective length of the tonearm.

Making multiple protractors (e.g. 237, 238, 239, 240, 241) could get confusing - spaced .5 mm or 1 mm apart.

As I mentioned to you (and by inference to all Schroeder and SME owners) you needed to be prepared to return to your two-point alignment - in the event that the position of the stylus relative to the mounting bolts renders an effective length significantly different from the 239 mm specification.

Lady luck was on your side, as when I measured my Universe with dial calipers, the distance was very close to 9.25 mm. It came in at 9.2. [edit] we later looked up this dimension in the owner's manual. it is 9.0 mm for both the Airy-3 and Universe [... end edit]


Cheers,
Thom

[Dan_ed]

My postman saw fit to bend the package so it would go into the mailbox. It didn't crease but I've had it under some heavy books to try and take the curl out of it.

The only thing I'm a little uncertain about is getting the line really centered on the pivot point. This is easy to do accurately with a mirrored protractor and a length of thread. Any tips on doing this with the card-stock?

[dmailer]

I used a thread to help line up and it did a pretty good job. I think though that the stylus will line up accross the arc only if it is at the proper distance. (Thom let me know if this is not correct). I used the thread to get close and then made my adjustments on the armpod until I got the stylus to trace the arc.

[ralph@artisan]

The only thing I'm a little uncertain about is getting the line really centered on the pivot point. This is easy to do accurately with a mirrored protractor and a length of thread. Any tips on doing this with the card-stock?

I'm taking the view that you will only get the arm to trace the correct arc if the pivot is at the right distance from the spindle. It's quite effective to trace the arc with the arm in the raised position. Even if you can't see the stylus (like on an Artisan Cadenza and Soundsmith Strain Gauge) you can sense whether the cart body overhanging the arc is increasing/decreasing.

The same is true for lining up the pivot to spindle line with the pivot point. Once the protractor is correctly orientated on the platter, then I adjust the effective length (stylus on the arc) and finally align the cantilever at the null point.

We have been using this method with the Artisan arm since last fall, which I think helps account for why it has sounded so good on the Serac, with relatively modest cartridges (e.g. Dyna 20X)

Ralph

PS I'm off to Munich High End tomorrow - any interest in a report?

[palasr]

Ralph has it correct - the beauty of the arc-based protractor is that there is no need to visually line up a "projector" line from the spindle to the pivot point (which introduces its own set of errors) IF your spindle to pivot distance is correct (in the case of a Triplanar, 233.5 mm). Now it is simply a matter of confirming correct overhang so that the stylus falls exactly on the arc at two points (generally near the spindle and beyond the edge of the platter) - this is accomplished by moving the cartridge in the headshell, as is final alignment to the grid null points to insure the cantilever is parallel to the grid/crosshairs.

I have long sung the praises of arc-based protractors - no "universal" two-point portractor I've ever tried (and I think I've tried nearly all of them, including the near-useless Feickert) comes even remotely close to a decent arc-based alignment. When I owned my Linn, I had a Wallytractor and loved its intuitive simplicity, as well as its excellent parallax elimination. Since I've never been able to cajole Wally into building me one for my Triplanar , I sought an alternative a couple of months ago in the Best Tractor from Hong Kong:

http://www.mintlp.com/best.htm

I can highly recommend this affordable protractor for folks looking for (yet?) another alignment tool - each is specific to a particular tonearm, so have your data handy - the owner, Yip, is a nice guy, and delivers promptly. The protractor itself is made of plate-glass mirror, with the arc and alignment grid silk-screened onto the glass. Pretty spiffy - the alignment grid lines are so fine, at least 4X magnification is required to see the lines, which merely adds to the excellent resolution of the device. I also recommend the use of a hands-free magnifying device such as this folding magnifier sold by Edmund Scientific which is 4X/6X/10X and is of decent quality:

http://scientificsonline.com/product.asp_Q_pn_E_3038657

-Richard

[galibier_numero_un]

Richard and Ralph have it nailed as far as the process is concerned.

In talking with Larry on Friday, the question first arose about sighting in on the tonearm bearing from the record spindle, and I immediately regretted leaving that construction line in the drawing. It can give you only the roughest of starting points and you can quickly and easily do better.

A better way to get the general orientation is as Ralph mentioned. Leave your tonearm in the cued up position and watch the arc traced by the tonearm. This will also help you visualize the process you'll be following, because the required pivot-spindle adjustment will likely not be obvious to you initially.

With the arm cued up, rotate the arm back and forth and watch the arm trace the arc. Perform some gross rotational adjustments with your armboard (Galibier), and once you're comfortable, get down to business in the cued down position. With a traditional, fixed armboard, your hope is that there's some play in the mounting holes, that the arm was mounted reasonably close, and that you can achieve the level of precision that an arc-style protractor demands.

Note that if your fixed-mount armboard will not permit the correct pivot to spindle distance to be achieved, we can always work around this problem with a protractor drawn for a slightly longer or shorter pivot-spindle distance, making this up in the headshell slots according to Baerwaald's equations. The beauty of the card-stock protractors is that they can be configured on the fly to any geometry with zero manufacturing cost. This is a particular advantage when mounting Schroeder DPS and References, as well as SME's with their fixed (fore-aft) mounts on the headshell. For these arms, you really need multiple protractors based on the distance that the stylus falls ahead of the mounting bolts (read the FAQ link in the first post in this thread). The down side of these card-stock protractors is that they're not quite as pretty, precise, or durable, although they're far more precise than any two-point protractor.

The biggest head-scratcher involves deciding what to do first. Once you get past this, you'll realize that you've parsed up the problem into manageable steps.

Edit (December 4, 2009): added height dimensions to cartridges

As I walk people through this process, I've been thinking about this more. Two things will simplify your life:

• Start off with as precise a pivot to spindle distance as you can measure.
  
• Do your best to position your cartridge in the headshell so you are close to the intended effective length of the tonearm.
  
  If you know the position of the stylus relative to the cartridge mounting bolts, you'll have an easier time establishing the bearing pivot to stylus distance (the effective length of the arm).
  
  We'll update this list of cartridges' stylus position relative to the mounting bolts as information becomes available. Note that (where known), I've also indicated the height of the cartridge - from the mounting surface (bottom of headshell) to the stylus tip. This can be useful when making cartridge swaps and roughing in the VTA setting:
  
  * ZYX (Airy-3 /Universe): Offset=9.0 mm, Height (mounting plane to stylus)= ??? (from owner's manual)
  * Denon DL-103R: Offset=7.5 mm, Height (mounting plane to stylus)= 15mm (from cartridge data sheet)
  * Dynavector 10X5: Offset=8.5 mm, Height (mounting plane to stylus)= 18.8mm (from manufacturer's drawings)
  * Dynavector 17D3: Offset=9.4 mm, Height (mounting plane to stylus)= 16.2mm (from manufacturer's drawings)
  * Dynavector XX2: Offset=8.5 mm, Height (mounting plane to stylus)= 18.7mm (from manufacturer's drawings)
  * Dynavector TeKaitora: Offset=8.3 mm, Height (mounting plane to stylus)= 18.7mm (from manufacturer's drawings)
  * Dynavector (XV-1s / XV1t / XV1s mono): Offset=8.0 mm, Height (mounting plane to stylus)= 21mm (from manufacturer's drawings)

... end of edit - December 4, 200


Edit (May 28, 2008):

Procedure

• Begin by refining the pivot to spindle distance until you see no improvement. In your first iteration, your best effort will likely position the stylus to that it traces an arc ahead of or behind the arc by a few millimeters - depending on how accurately you set the cartridge's position in the headshell.
  
  Concern yourself only with tracing an arc with the stylus that is concentric with the one on the protractor. Do not try to position the protractor so that the stylus lands on the arc. This will confuse you. Position the protractor instead with a view toward understanding how far off you are from concentricity.
  
  
• Turn your attention to the effective length adjustment (position of the cartridge in the headshell).
  
  At this point, your arc fairly well traces the arc concentrically.
  
  Let's say for example, the stylus lands some 2mm behind the arc at all points. Slide the cartridge forward in the headshell and check the change.
  
  You will likely need to return to fine tune the pivot to spindle distance - iterating between these two steps one or two times.
  
  
• Now, set the offset angle by rotating the cartridge in the headshell so that the cantilever lands on the solid line that intersects the arc and is collinear with it. While the protractor is not mirrored, if you use a magnifying glass, you'll get a fair amount of parallax correction and can be surprisingly accurate.
  
  
• Re-check that you are still tracing the arc perfectly.

Hint: when fine tuning the pivot to spindle distance, correct the observed error at the lead-in groove as follows:

• Start by rotating the protractor so the stylus lands on the arc at the record spindle side and observe the error at the lead-in groove.
  
  
• If the stylus lands behind the arc at the lead-in groove, increase the pivot to spindle distance slightly. Work a millimeter or less at a time. Re-position the protractor so the stylus lands on the arc at the record spindle side, and observe any improvement in the error at the lead-in groove.
  
  
• If the stylus lands in front of the arc at the lead-in groove, reverse the above adjustments.

Know that when working the record spindle side of the arc, a change of a millimeter in pivot to spindle distance will result in several millimeters of tracing change at the lead-in groove. Keep this fact in mind as you work, and know that by working at the extreme ends of the arc, that you magnify the precision of your adjustment.

Note that the lines on the protractor are .012" wide. I would shoot for landing on the line at all points of the arc. I have yet to work to finer tolerances (e.g. trying to stay in the middle of the line throughout the tracing of the arc). [/list]

... end of edit - May 28, 2008

I'm not sure if I'll carry the project beyond this card-stock iteration, as I take Richard's recommendation of mintlp.com to heart. If we can come up with a cost effective means of building a better mousetrap, we'll likely take this project over the finish line. The next few months will tell the story.

BTW, I have the highest trust in Richard's recommendation of mintlp.com. He's been playing this game for quite a while and has a discerning ear.

Cheers,
Thom

[Dan_ed]

Thanks all,

I understand now how this is supposed to work. Hopefully my protractor will be flat by this weekend so I can try it out. If no, I'll tape that sucker down.

So, am I correct to assume we probably couldn't get a bulk rate from Yip at mintlp since there are many different specs involved?

[galibier_numero_un]

Hi Dan,

I would expect that we could easily get the interest of 10 Triplanar owners between the active surfers of this forum, Doug and Paul and a few customers who don't follow this forum on a regular basis.

I'd find this interesting because if I learn that Yip's protractor is as good as it gets, I have no interest in building a better mouse trap. I have my eyes on some other projects in the next 18 months, and burning time on something that someone else has already perfected is a distraction from landing bigger fish.

I'd still work on manufacturing Artisan protractors. Likely, the purchaser of an $800 tonearm would not be inclined to invest big bucks in a protractor - not knowing how much it can deliver out of proportion to the funds outlay. Ralph and I are committed to these arms and to adding value to them in ways beyond the capability (or vision) of the average distributor.

I took the first step today while at my machinist. We're doing some test engraving on acrylic. From there, I'll evaluate whether I want to silkscreen them instead (doubtful).

Cheers,
Thom

[Dan_ed]

What are all of the parameters needed to make each protractor? Is it only 'table/tonearm specific?

Thom,

My only concern with acrylic is the potential for the stylus to scratch it up. I see this with the mirrored protractor supplied with my Vector, which I believe is plastic and not glass. The surface takes on a foggy appearance around the crosshairs due to the minute scratches made by the stylus. This makes it a little more difficult to see.

[galibier_numero_un]

Hi Dan,

I know that Yip shoots for a precise fit in the spindle hole and toward this end asks its diameter. Richard specified a .283" diameter hole for his protractor. I have to go back to my drawings, but my spindle is either .280 or .281.

In any event, by specifying .283, Richard sez it's scary tight and requires his attention to lift without tilting. From his description, it sounds to me to be similar to fitting the Galibier bearing into the body.

If someone asked me about other parameters, it would be three other specifications:

1. effective length (250 mm for Triplanar)
2. alignment (e.g. Baerwaald)
3. Platter diameter

Platter diameter is merely a convenience issue, so that the curved edge of this circle quadrant shaped piece ends at the edge of the record playing surface of the platter. This will make it easier to lift off the turntable. For Galibier owners, this number is 11.650" which makes for a platter to record contact that ends at the middle of the record lead-in groove. This is before most records begins to thicken to create a downward slope toward the lead-in groove. More free (but irrelevant to protractor construction) information compliments of Galibier

If I were ordering, I'd likely confirm the numbers for pivot to spindle and offset angle that I get out of Ellison's spreadsheet to see if we were in agreement.

Your point about acrylic is well taken. I've had a two-point mirror backed acrylic protractor for some 20 years (made by either Ortofon or Thorens - I can't recall which). I don't see any scratch marks on it which may point to either different handling by you and me, better eyesight by you, or a different hardness of acrylic.

The way I look at it, stylus health is the most important consideration, and I don't know what to make of the whole diamond is harder than anything philosophy. On one hand, I'd like to be sure that diamond always wins in the game of "rock, paper, scissors, match" (kids game for our non-American readers).

On the other hand, if diamond always wins this game, then even polished aluminum or stainless will scratch the protractor's surface. My preliminary thoughts are to machine small grooves and then to fill them in so that the stylus doesn't snag in the grooves. I'm still pondering the best approach to accomplish this, however. The first test grooves I get from my machinist will hopefully be instructive as to whether or not I'm all wet in my approach.

Cheers,
Thom

[palasr]

As far as I know, Yip will only manufacture a Baerwald geometry (I was given no option), although I'm certain he could accomodate if you asked for Loefgren. Beyond that, spindle diameter, pivot-to-spindle distance and effective length (overhang) were all that Yip required.

I gave Yip an extra thousanth on the spindle diameter I physically measured on my Gavia, and it is tight - I can get no more than 15-20 degrees of deviation away from horizontal before I feel I should quickly return to something more level. Nothing to be afraid of, but something to note -- be gentle. The alignment grid lines themselves are probably on the order of .008", give or take .002". I belive Yip told me the one he made for himself uses .005" lines, but he does not market it as "this would drive most people insane". I commend the man for his accuracy.

Cheers,

-Richard

[galibier_numero_un]

Yip sounds like one of us, and hopefully, none of us will take up residence in the "rubber Ramada" due to our fastidiousness.

The line width is interesting. My machinist is looking at lines either .008 wide by .010 deep or the reverse (I forget). For reference, the printed lines on the card-stock arc-style protractors I've been printing are .012" wide.

Cheers,
Thom

[Jim Hagerman]

Too much math maybe? How about adjusting the cart by ear until it sounds perfect. Then put the card stock under it and jam the stylus down as hard as you can, leaving a nice little indentation to let us know where it should go.

jh