Vinyl Asylum Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ.

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ Vinyl Asylum ]

---

[ Alert Moderator ]

---

I have discovered what I believe to be a more accurate method of measuring arm/cartridge resonance....

Posted by John Elison (A) on February 1, 2007 at 09:10:15

If you read my previous post on the inaccuracy of the resonance test tracks on the HFNRR test record, you will understand my disappointment with that test record. Because of this I took another look at the Cardas test record and I discovered something interesting.

Tracks 8a and 8b on side one contain 49-Hz test tones recorded both laterally and vertically. I decided to use these tracks to measure arm/cartridge resonance by removing the belt to my platter and spinning the platter by hand. As the platter slows down and finally stops, the arm/cartridge resonance is displayed quite distinctly as is evidenced in the following picture from Sound Forge 7.0 of the vertically modulated groove.

Another picture shows the laterally modulated groove, which I've spread out a bit so you can see the oscillations more clearly.

I can spread the signal out even further around the point of resonance and actually count the samples of a waveform to determine its frequency. Sound Forge 7.0 has a statistics function that allows for this.

These pictures represent the arm/cartridge resonance of an AT33PTG mounted in a SME V tonearm. I think it's interesting to note that the two channels have different resonance frequencies. I'm not exactly sure why that is because I expected both channels to have the same lateral resonance and also the same vertical resonance, although perhaps different lateral and vertical resonances. Anyway, here are the results.

Left Channel Lateral = 6.875-Hz
Right Channel Lateral = 8.125-Hz
Left Channel Vertical = 6.942-Hz
Right Channel Vertical = 7.914-Hz

Average of all four = 7.464-Hz

Cartridge weight with fasteners = 7.70-grams
Tonearm effective mass = 10.5-grams
Calculated Cartridge Compliance at resonance = 25-cu

Specified Cartridge Compliance Static = 40-cu
Specified Cartridge Compliance Dynamic @ 100-Hz = 10-cu

Conclusion: The AT33PTG seems to be a high-compliance cartridge that would perform most optimally in a low-mass tonearm.

Best regards,
John Elison

This post is made possible by the generous support of people like you and our sponsors:

Parts Connexion

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---