Instructions for a Turntable Basics Protractor

Doug,

My side-mounted armplate (which is adjustable)for my Acoustic Solid turntable is set exactly at 220mm so we are in business. Now, if my new upgraded arm (it's a Rega platform)would arrive, I really would be in business.

Thanks again for your help.

Rega arms are not designed for Baerwald alignment. The standard Rega mounting distance of 222mm puts the arm too far from the TT spindle for some cartridges to reach both Baerwald null points. You'd have to move the cartridge farther forward than the headshell slots allow.

If you have a moveable armboard the fix is simple however. Just mount the arm at 219.5-220mm. At that distance any cartridge should reach the Baerwald points without difficulty. I did this successfully with an OL (Rega mount) arm on a Teres (pivoting arm board) and so have many others.

Alternatively, you could use a Rega protractor and mount the arm at the standard dimension. Baerwald alignment tends to produce lower tracing distortion than Rega alignment, however, so that's probably the preferable method.

Doug,

I appreciate your follow-up. I am setting up a new system (Acoustic Solid TT) with Rega arm, so I believe the Baerwald method would be appropriate?

I also have a Grace 707 MK II tonearm on another turntable which I successfully used the Turntable Alignment Tool several years ago. If I am not mistaken both the Rega arms and the Grace 707 both have an effective length of 237mm and a mounting distance of 222mm.

A laser leveller does work but a thread (not "string", I misspoke) is actually more accurate - thanks to the parallax effect. Sometimes simplest is best. :-)

One thing we ought to have asked is, what tonearm/turntable are you planning to use this protractor with? If your rig isn't Baerwald compatible then this whole discussion is moot.

Again, I appreciate all of your help.

If I am not mistaken, I believe that I have read that using a auto leveling laser light which can be purchased from Home Depot or Lowes could be used in place of the string.

No problem Mark. It was Frank Schroeder who taught me the string trick. We all learn from each other!

I have this tool and the instruction sheet that came with it.If you want to send me your snail mail address I'll copy the one page and mail it to you (for free even).Casey.

Sorry Doug that I failed to mention it was you who taught me these good tricks to enhance effectiveness with this Protractor. I feel it at times it is impolite to mention another person's name without thier permission.

Thank you for adding, and reminding us about the parallax error, and how the aligning both first surface, and reflected lines will enhance alignment while looking at the grid. Mark

In addition to Markd51's good instructions, the trick to using the TTB well is to get your eye used to the parallax (dual images) from the mirror. Some people find this distracting, but in fact it is the best feature of the TTB and the one that makes it more accurate than non-reflecting protractors.

Once you get the hang of looking at both the direct and reflected images of the grid, and squaring them up, you can be certain you're looking exactly down the centerline of the grid. That kind of accuracy isn't possible with a single image protractor.

This takes some practice, so I'd encourage you to align and re-align your cartridge several times. The more often you do it the better you'll get at it.

As Markd51 said:

1. Align the sight line to the tonearm pivot using a piece of thread (WAY more accurate than just looking down the line).

2. Place the stylus on the outer grid and square the CANTILEVER to the grid. (Ignore the cartridge body). If you do this "perfectly", the inner grid becomes theoretically superfluous.

3. Move the protractor and recheck cantilever squareness with the stylus on the inner grid. (Just a double check).

4. If it's not square, iterate back and forth between grids until it's square on both.

Doug

Thanks for your helpful responses. Before this post, I attempted contact with TurntableBasics requesting the instuctions. After several attempts, I have not received a response.

Turntable Basics would probably send you a set of instructions if you contact them, and tell them you've lost your instructions, and would like to have them.

The Protractor is not that hard to use. You'll note a hole in the Protractor, and this slips over the Platter Spindle. There is a sight line on the left side of the protractor that runs it entire length, and this sight line must be pointed to the exact center of the Tonearm Pivot to accurately work.

If you're sloppy in this area of alignment, you'll be pretty much wasting your time, as there will be error.

What was suggested to me another good audiogon friend, is to tape a thread at the beginning of the line on the protractor, and use this piece of thread to enchance the aiming accuracy of the sight line to the Tonearm Pivot.

Make sure the thread is exactly on the beginning of the protractor sight line, then pull the thread taught holding the thread to the exact center of the Tonearm Pivot. Now rotate the Protractor on the spindle, while viewing the thread, and the protractor sight line simultaneously, and adjust till the super-impose over one another.

Without moving the protractor, then begin to adjust overhang of the Cartridge until the Stylus itself is exactly within the outer alignment grid's little center box.

Do contantly re-check, with the sight line as you go, making your adjustments to the Cartridge, both as far as overhang go, and Zenith Alignment (the the Cartridge is square-aligned to the lines on the Protractor Grid)

Once you have gotten proper alignment to the Outer Grid, then follow the instructions on the protractor, thus rotating it till you can then set the Stylus on the inner Grid's central reference point. Note how the Cartridge is aligned. if Zenith Alignment is off, slightly compensate back, and forth between the two grids till you get the best possible Zenith Alignment.

This will be your basic Alignment, but do keep in mind that some Cartridge Bodies can be a muther, thus hindering your best attempts (Body isn't square, or a short-low riding Cantilever makes the Stylus hard to see.

As has been told to me, it is the Cantilever, and Stylus itself that must be aligned to the Grid. The Body-Cantilever alignment can be ever so slightly off, even on the best Cartridges.

Do try to use lighting at various angles aimed towards the Stylus (experiment) to help aid what you're seeing, and I've even used a lighted Magnifying Glass so I could better see exactly how well my Cantilever was aligned to the Protractor Grid. Mark

This is probably an overhang alignment tool. If it is, it probably has a grid imprinted on it with an indication (either a hole or a cross hair indication for you to punch a hole)for slipping over the spindle. My suggestion is that you put a piece of tape or 2 to imobilize the turntable platter before you start. Once the tool is on the spindle, move your tonearm with cartridge attached so that the sylus gently rests on some indication..either an x or a dot which has been printed on the tool. If it cant reach this dot, or is too far forward of this dot, loosten the screws that secure the cartridge to the arm, and move the cartridge along the slotted holes of the arm so that the stylus sits right on the x or dot. You also must be sure that the cartridge is square within the indicated lines. Sometimes the arm itself may not be square to these lines, but your concern is the cartridge. If there is no slots in the headshell to accomplish this, the whole arm has to be moved - this adjustment is very important for good sound. Sei gazundt