In This Series
- 1 How Do Vinyl Records Work?
- 2 Components
- 2.1 The Platter
- 2.2 The Bearing
- 2.3 The Motor
- 2.4 The Tonearm
- 2.5 The Cartridge
- 3 Phono Stages
- 4 Should You Buy an All-In-1 Turntable?
- 5 The Current Market
- 6 How to Setup a Turntable
- 7 How to Install and Align a Turntable Cartridge
- 8 Optimising The Sound
- 9 Purchasing a Used Turntable
- 10 Turntable, Tonearm and Cartridge Specifications
- 10.1 Tonearm Specifications
- 10.2 Turntable Specifications
- 10.3 Cartridge Specifications
- 11 Turntable Drive Systems
- 12 Recommended Tools
- 13 Free Protractors and Strobe Discs
- 14 Conclusions
Below are some downloadable PDF arc protractors, used to align a cartridge to various standard null radii. Be sure to choose a protractor that matches your arm or turntable, as the accuracy of these protractors relies on the pivot to spindle distance being correct. You’ll also want to print the protractors to scale, which you can verify by measuring the provided points on the protractor.
There are 2 popular alignment families, known as Baerwald (or Lofgren A) and Stevenson. The 2 alignment geometries are calculated to minimise tracking error and distortion. Lofgren A or Baerwald alignment spreads the distortion across the surface of the record, resulting in the lowest average distortion figures. Stevenson alignments are optimised for zero tracking distortion in the lead out groove of the record at the expense of slightly higher distortion everywhere else. In reality the distortion figures are so low as to be of little issue. If your turntable manufacturer specifies an alignment, it is best to stick with their recommendation. If not, a Lofgren A protractor usually offers the best performance across a majority of LP records.
Technics 1200, Technics Alignment
This protractor will align a cartridge to the factory Technics alignment, the same that is achieved when using the supplied overhang gauge. This protractor offers an extremely accurate way to align your cartridge using the Technics null radii of 58.8 and 113.5MM, resulting in an overhang of 15MM and an offset angle of 22 degrees, exactly as specified by Technics. When aligned, your cartridge body should be parallel to the headshell, with the distance between the tip of the stylus and the rubber washer at the rear of the headshell exactly 52MM.
Technics Lofgren A (Baerwald) Protractor
Another protractor for the Technics, this time aligning to the Lofgren A or Baerwald alignment, with IEC standard null points of 66 and 120.9MM. When aligned, the cartridge will sit further forward in the headshell, angled slightly inwards. This alignment offers less RMS and peak distortion than the factory Technics alignment, though you may find the difference to be subtle at best. I prefer the Technics alignment. This protractor will work with any tonearm with a mounting distance of 215MM.
Rega Lofgren A (Baerwald) Protractor
A Lofgren A protractor for Rega arms mounted at 222MM, aligning to the IEC standard null points of 66 and 120.9MM. Most Rega arms follow the 222MM mounting standard, including the RB300, 301, 303, 330, 808, 2000 and many others.
Universal 2-Point Protractor
A universal protractor can be found at EnjoyTheMusic.com and is a simple 2-point protractor which can be used with virtually any cartridge combination to achieve a baerwald alignment. While a little crude, this protractor works well if you don’t know the specific pivot to spindle mounting distance of your turntable and if your turntable wasn’t provided with an alignment gauge.
Other protractors can be downloaded from the Vinyl Engine. The vinyl engine also hosts a database of nearly every turntable, cartridge and tonearm ever manufactured along with their specifications and in many cases both instruction and technical manuals, as well as a range of tools for calculating optimal cartridge alignment, tonearm mounting position and tonearm / cartridge resonant frequency.
Creating Your Own
If you know the pivot to spindle distance if your arm, creating your own protractor is a simple task. This Arc Template Generator will calculate an arc protractor like those above based on your tonearm mounting distance, desired null radii and any of the 3 common alignment families.
These discs will allow you to check the speed of your turntable. Again, they should be printed to scale, and be sure to use the disc suitable for the electricity supply in your country (50Hz in the UK). Better results can be attained using the Turntabulator app for iOS.
This article is part of our Guide to Turntables and Vinyl series. Continue reading: Part 14, Addendums, glossary of terms and Conclusions.