Home Vinyl Asylum

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

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Vinyl Asylum ]
[ Alert Moderator ]

RE: Does speed stability even matter?

Well, to my thinking and experience, movement of the disc, especially since force is being exerted upon it by the cutter of the lathe, must be an issue. I experience this on playback with felt TT mats and am a strong advocate of a clamping system.

You certainly don't want any slippage of the lacquer as you are cutting it. I am assuming you have seen pictures of a cutting lathe. The cutter head has a heated blade and a vacuum attachment, but the lacquer itself does not seem to have a clamping mechanism. I wanted to rule out any speed variations of the lacquer/platter interface, and I, apparently, seemed to have glossed over that fact. My apologies.

Since some manufacturers employ DMM processing (Direct metal mastering) The cutting blade is actually cutting metal directly and there will be considerable resistance to the blade.

In doing a bit of research, I found this on the Neumann AM-32 lathe. The motor is a synchronous type with a "gear like armature about 10 inches in diameter, rotating inside a similar inside gear." The quotes are because I can't quite picture what they are describing. The wow and flutter is spec'd at +/- 0.035 % RMS. The platter weight is given at 65 pounds, and is coupled to the motor via an oil filled coupling to lower motor noise. This is from "the Handbook for Sound engineers": Glenn Ballou, ed. The oil coupling seems to be a sort of automatic transmission to me.

According to the Neumann article in Mix magazine, Neumann invented direct drive cutting lathes in 1931, so I guess the boom in DD TT's in the 70's came about from the Japanese manufacturers emulating the cutting lathedrive systems. It also means that their lathes had a pretty heavy duty motor if it was 10 inches in diameter. The torque produced by an armature of that size can be tremendous and the oil coupling would smooth out motor noises.

Most Scully lathes have a gear drive, and I would guess a hyploid drive would give the smoothest power transmission and speed stability, but I am totally unfamiliar with the underpinnings of a record lathe having only seen pictures and a description from the top exterior point of view. They did have a gear box from what I can research. Considering they were made in the 40's, I would guess that they use straight cut gears.

But since these common cutting lathes feature things like direct drive and gear drive, my guess that speed fluctuation would be minimal.

I believe, in playback, motor EMF field proximity to the magnetic cartridge, belts stretching while in play, suspension twisting, cartridge design probably all have greater effects on the sound than the original cutter lathe speed. Just consider how much laser cutting of styli have affected sonics, even on LP's pressed at the beginning of stereo. The issue has always been more on the playback side, rather than the manufacturing side.

Of course, YMMV.

Stu


Edits: 08/02/07
This post is made possible by the generous support of people like you and our sponsors:
  Kimber Kable  

Follow Ups Full Thread
Follow Ups
FAQ

Post a Message!

 Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
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.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]