Clearaudio Alignment Gauge vs Dr. Feickert Protractor NG

[Josquin des Prez]

Re-reading the article I linked above, and the comments about the Rega setup, it looks like I confused inner null points with innermost recorded groove points, so some of my original points are wrong.

On the Clearaudio scale, the r=60.325, 65, 70, and 75 represent innermost recorded groove, not inner null points. The inner null points actually vary according to arm mounting distance. For my Magnify arm, with a mounting distance of 222mm, the inner and outer null points are as follows:

r=60.325: 67.67, 117.90
r=65: 72.40, 120.68
r=70: 77.39, 123.38
r=75: 82.32, 125.82

For Baerwald null points are 66.0 and 120.9 mm, so the Clearaudio r=60.325 (IEC) is nearly the same.

For Lofgren null points are 70.3 and 116.6 mm. Clearaudio's r=65 seem to correspond most closely to that. For Stevenson null points are 60.325 and 117.42 mm, similar to what Rega favors. There is no close counterpart on the Clearaudio.

[MyPal]

Originally Posted by Josquin des Prez

[Edit: some of my original points here are wrong, confusing inner null points with innermost recorded groove. I have not corrected that here. See post #11]

I have been using the Dr. Feickert Protractor NG with my Clearaudio Ovation/Magnify/Talisman with the Baerwald geometry, and that has worked well for me.

This weekend I borrowed my dealer's Clearaudio Alignment Gauge (protractor) and it has different geometries. It includes the IEC standard (r=60.325mm) inner null point (Stevenson), but also has alternate geometries for r=65, r=70 and r=75mm (which Clearaudio calls their 3rd, 2nd, and 1st recommendation, respectively). The r=65 corresponds roughly to Baerwald (r=66.0). There is an article at VinylEngine that analyses the Clearaudio protractor and they give it a thumbs up.

The argument for the 70 and 75 mm inner null points is that most audiophile records are not cut that close to the spindle and a larger inner null point renders better geometry overall. However, if you do get closer than the r=70 or r=75 inner null point, the increase in distortion from tracking error rises more dramatically.

I decided to try a compromise and align my cartridge with Clearaudio's 2nd recommendation of r=70mm. That brings my cartridge just a bit more forward in the headshell, which I like for the unrelated reason that it provides a little more room behind the cartridge body for the very delicate and fragile leads of my arm cable.

I listen to all classical and jazz, and have a mixtures of old recordings and newer reissues. I have been listening to my altered setup with r=70mm and so far I like what I hear. From the beginning of the record side to at least the middle I think it sounds better. I believe I notice an improvement in imaging and resolution, but I can't say for sure. I set it back again and thought it didn't sound as good, so now I set it back again to r=70mm. I like what I hear.

Anyone else using alternate geometries for cartridge alignment? Thoughts?

Dean... When I mounted the GFS on the MT10's 222mm radius, I went with the CA 1st recommendation, r=75. On the most part, I am happy with the choice. I have noted some minor distortion on some LPs on the last 5s or so of play. I may give r=70 a go at some stage but am loathed to touch the screw torque because azimuth is spot on!

[Josquin des Prez]

Originally Posted by MyPal

Dean... When I mounted the GFS on the MT10's 222mm radius, I went with the CA 1st recommendation, r=75. On the most part, I am happy with the choice. I have noted some minor distortion on some LPs on the last 5s or so of play. I may give r=70 a go at some stage but am loathed to touch the screw torque because azimuth is spot on!

I have been going back and forth between r=65 and r=70. Right now I am at r=70. Both sound good to me.