33.3RPM @ 100Hz

33.3RPM @ 120Hz

45RPM @ 100Hz

45RPM @ 120Hz

  Well, there's no place like home. Home is where my turntable is and everyone should have a two point protractor.

In Use: The trick is to have the cartridge mounted so that the needle aligns perfectly on BOTH dots without moving the protractor. What you may need to do is mount the cartridge a bit loose and slightly move it forward or back and see how it aligns on both points. You know you have it perfect when both points are perfect without moving the protractor. It takes time and patience to get it just right, but the results are worth it!

As always, if you have any questions please feel free to e-mail them to me. Thanks!

  Due to the tremendous outpouring of requests for an easy to print version, we are now offering a PDF version! There are some caveats to this... When printing make sure you set your printer to "Print as image" and do not have it "Fit to page". The free Adobe Acrobat Reader plug-in is needed, though most people already have this installed within their computer. Please click the below link print the file.

Click here for cartridge alignment tool

Click here to view the two point protractor in action.

 

 Goddesses/Dudes,

   For those desiring a preprinted version, this protractor tool is used for your vinyl turntable  to insure proper alignment of the cartridge on your tonearm. This version is printed on a high quality cardboard sheet  4 inches wide by 7 inches long (DL or a C5 envelope for my European and overseas friends).  All i ask is that you send your request with a self addressed stamped envelope inside that will fit the protractor to the dude nearest to you. Below is the listing of the locations where it is available for free:

 

Mike Clapperton  21 Anthony Drive  Gillitts  3610  KZN	Melbourne Audio Club Inc P.O. Box 27  Forest Hills Vic  3131 Australia
David Baier Mariahilfpark 4/411 6020 Innsbruck	Sead Lejlic Alipasina 45-a 71000 Sarajevo Bosnia and Herzegovina
Tony Maresch 5th Floor, 6075 Yonge St. Toronto, Ontario M2M 3W2 Canada	Jacques Daigneau 46 avenue du bois de verrieres 92160 Antony France
Hartmut Quaschik Strassl ins Holz 19 81829 Munich Germany	Dr. Lucio Cadeddu Dept. of Mathematics University of CAGLIARI Via Ospedale 72 09124 Cagliari Italy
Paul K K Chin 156, Holiday Park, Bakam, 98000 Miri, Sarawak, Malaysia	André Huisman New Line licht en geluid Kanaalweg 100 b 8861 KJ Harlingen Netherlands
RJ 392 New Brighton Road New Brighton Christchurch New Zealand	Geir Braendvik Department of Philosophy P.O. Box 1020 Blindern N-0315 Oslo Norway
Gerry Kaimo n/a records 910 W PSE Bldg. Exchange Rd. Ortigas Center Pasig City 1605 Philippines	Iain A F Fleming 8 St. Magdalenes Linlithgow West Lothian EH49 6AQ Scotland
Melvin Ang 43 Jalan Haji Salam Singapore 468831	Ashley Chua BLK 319, Shunfu Road #03-10 Singapore 70319
Claudio Rodil Felipe Campos, 18 Primera Planta 28002 Madrid Spain Por favor enviar sobre tamaño oficio americano franqueado y con dirección.	David Lundin Gjuterigatan 3A 33142 Värnamo Sweden
James Chang 11F, No. 216, Wen Lin North Road, Taipei, Taiwan	Teeranut Vanitchayanguranont 45/10 Damrongrug Road Klongmahanak Pomparb Bangkok 10100 Thailland
Dr. Simon Busbridge Dept. of Mech. and Manufct. Eng. University of Brighton Lewes Road Moulsecoomb Brighton BN2 4GJ U.K.	Todd Warnke 922 Oakwood Drive Castle Rock, CO 80104 U. S. A.
Prodanovic Aleksandar Santiceva 2 21420 BAC Yugoslavia

  You'll find an Excel 97 file at the link located below this article. It's a two page spreadsheet, one page for Baerwald alignment and one page for Löfgren "B" alignment. Interestingly, from all the reading I've done recently on the subject, it seems that Löfgren actually came first and figured everything out in 1938, then Baerwald came along three years later and published part of Löfgren's work taking credit for the so-called "Baerwald alignment process" or Löfgren "A." However, Löfgren's complete work contained an alternative alignment (Löfgren "B") that may actually be more advantageous than Baerwald's approach. At the core of both alignments lies the weighted tracking error curve, which is essentially tracking error per unit of groove radius.

This weighted curve places more emphasis on tracking error for inner grooves than for outer grooves, which is representative of the actual distortion caused by tracking error. The difference between the two alignments is that Baerwald's (or Löfgren's "A") minimizes the weighted tracking error curve directly while Löfgren's "B" minimizes the area underneath the squared weighted tracking error curve. IMO this translates into Baerwald minimizing peak distortion and Löfgren "B" minimizing RMS distortion. The advantage of Löfgren's "B" alignment is lower tracking distortion during more playing time at the expense of slightly higher distortion at the beginning and end of the record. Baerwald's (or Löfgren's "A") alignment minimizes and equalizes the distortion peaks at the innermost groove, in-between the null-points, and at the outermost groove.

Okay, so how does the spreadsheet work? Well, the easiest way to operate the spreadsheet is by using the Baerwald or Löfgren calculator at the top of the spreadsheet page. The calculator has three yellow input cells and six green output cells. Inputs are effective length, innermost groove, and outermost groove. Outputs are angular offset, linear offset, stylus overhang, pivot-to-spindle mounting distance, inner null-point, and outer null-point. The default or initial input values are 228.6mm (9") for tonearm effective length and the IEC standard innermost and outermost groove radii of 60.325mm and 146.05mm, respectively. The output values change in accordance with the equations listed in the instruction area below the graph when new numbers are entered into any of the yellow input cells.

The graph is a visual representation of the columns of numbers on the left, which are a function of three specific tonearm parameters, effective length, angular offset, and stylus overhang as displayed in the tan colored cells, A3, B3, and C3. These are also spreadsheet input cells, but initially they are linked to the corresponding calculator cells, I3, O3, and Q3 so the calculator controls the entire spreadsheet. However, the tan colored cells may easily be unlinked from the calculator simply by entering numbers into them. If this is done, the calculator operate autonomously from the rest of the spreadsheet. The graph and the rest of the spreadsheet are controlled by inputs to cells A3, B3, and C3 only. One reason for unlinking the calculator might be to evaluate a tonearm's geometry by inputting effective length, angular offset, and stylus overhang directly into cells A3, B3, and C3, respectively. You'll find some interesting designs floating around out there with alignment geometry's based on something entirely different from either Baerwald or Löfgren "B."

For advanced spreadsheet users, the Excel "Solver" function is a very powerful tool that can be used advantageously with this spreadsheet. "Solver" lets you turn output cells into input cells through an indirect iterative mathematical process. For example, suppose you wish to evaluate Steven Rochlin's alignment tool, which has alignment null-points at approximately 70mm and 127mm. You could ask "Solver" to find new innermost and outermost groove radii that would yield Steven's alignment null-points, and you would also get a graphical representation of Steven's tracking error and distortion curves. There are many ways "Solver" can be used to enhance and expand the capabilities of complex spreadsheets.

As a word of caution, only six cells on the spreadsheet should be used for entering numbers. They are the three yellow cells, I3, J3, and K3 in the calculator at the top of each page, and the three tan cells, A3, B3, and C3, which control the graph and the rest of the spreadsheet. Please do not enter numbers into any other cells, otherwise you may destroy important equations that enable the spreadsheet to function properly. As an additional precaution, I recommend you archive a copy of the spreadsheet and always use a different working copy, just in case something goes wrong and you want to return to the original. Other than that, have fun calculating.

 

Best Regards, John Elison JohnAFR@aol.com

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