Home Vinyl Asylum

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

RE: Null points for 7" discs?

> Consequently it is of greater importance to minimize the distortion at the innermost grooves

You used the plural form of "grooves" meaning multiple grooves. In other words, you seem to be talking about minimizing distortion across the inner groove area and not just at the innermost groove. You can accomplish this more effectively by placing the inner null-point in the middle of the inner groove area rather than at either end of it. This is what Lofgren's alignment does. This is why Lofgren's "A" alignment has the lowest distortion possible in-between a given modulated groove envelope whereas your alignment with the inner null-point placed exactly on the innermost groove will have greater RMS distortion throughout the inner groove area as well as throughout the entire modulated groove envelope.

On the other hand, it probably doesn't make that much difference since the modulated groove area on a 7-inch record is so small anyway. When you compare the distortion curves for a 12-inch record with a 7-inch record, you can see that a 7-inch record has much lower tracking error distortion as result of its smaller size. However, Lofgren's "A" solution for a 7-inch record still has slightly lower distortion than your solution.

Lofgren's "A" Tonearm Alignment for a 12-inch Record

Lofgren's "A" Tonearm Alignment for a 7-inch Record

Flood2's Recommended Alignment for a 7-inch Record

Edits: 07/08/17

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

Follow Ups Full Thread
Follow Ups


Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.