Tonearm mounting distance - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th May 2012, 12:27 AM   #1
diyAudio Member
 
Larry365's Avatar
 
Join Date: Apr 2012
Location: London
Default Tonearm mounting distance

Hi,

Is a Linn Lvx tonearm's mounting distance (211mm) critical?

I have searched the web and only seem to find mention of cartridge alignment.

What if my mounting distance is 195mm?

Thanks.
  Reply With Quote
Old 5th May 2012, 12:33 AM   #2
diyAudio Member
 
Join Date: Mar 2007
Location: Canandaigua, NY USA
I don't know anything about that arm, but in general mounting distance is critical. If the mounting distance is wrong there's a good chance you won't be able to achieve the desired alignment because the slots won't allow you to put the cartridge where it needs to be. The pivot to spindle distance is the fundamental dimension that everything else is derived from because it's usually the fixed dimension that you can't do much about.
__________________
I may be barking up the wrong tree, but at least I'm barking!
  Reply With Quote
Old 5th May 2012, 12:34 AM   #3
brianco is offline brianco  Ireland
diyAudio Member
 
brianco's Avatar
 
Join Date: Aug 2005
Location: Scottish Borders - Kelso; on the famous Tweed River!
ABSOLUTELY critical! Google tonearm geometry and read one or two articles on this subject.
  Reply With Quote
Old 5th May 2012, 06:04 AM   #4
diyAudio Member
 
Join Date: Apr 2008
Blog Entries: 1
Yes It is important, but the critical thing is that the overhang of your cartridge is appsolutly spot on. And I mean to 0.010mm or better. If this is not correct the distortion level increase dramatically. Also do not rely on the manufactures general guidlines. Go to VinylEngines Tonearm Alignment Calulator and type in your arm details. You may be suprised to see the best (lowest distortion) is different from what is recommeded by the manufacture.
Cheers
__________________
tabarddn
  Reply With Quote
Old 5th May 2012, 07:46 AM   #5
diyAudio Member
 
Join Date: Feb 2006
Location: Willy, VIC
Quote:
Originally Posted by tabarddn View Post
Yes It is important, but the critical thing is that the overhang of your cartridge is appsolutly spot on. And I mean to 0.010mm or better.
That makes no sense to me. Overhang is simply pivot to stylus length minus pivot to spindle length.

Assuming Baerwald's alignment, a 0.01mm change in overhang will increase the maximal distortion from 1.25% to a little under 1.26%. This is not a dramatic increase.

Last edited by Mark Kelly; 5th May 2012 at 08:08 AM.
  Reply With Quote
Old 7th May 2012, 12:09 AM   #6
diyAudio Member
 
Join Date: Mar 2007
Location: Canandaigua, NY USA
0.01 mm is not achievable. Cumulative bearing slop probably exceeds that and it would take fancy lab equipment to get that close even if the mechanics were up to it. IMO, overhang numbers should be entirely ignored because most tone arms won't go over center to even measure it and very often the published numbers are simply wrong. Better to use a decent alignment template, mine or others, and be secure in the fact that if the cartridge meets the conditions of the template, the overhang is where it needs to be.
__________________
I may be barking up the wrong tree, but at least I'm barking!
  Reply With Quote
Old 7th May 2012, 01:48 AM   #7
diyAudio Member
 
vinylkid58's Avatar
 
Join Date: May 2005
Location: Victoria, B.C.
Quote:
Originally Posted by Conrad Hoffman View Post
0.01 mm is not achievable.
Sure it is.

jeff
Attached Images
File Type: jpg Roy.jpg (7.3 KB, 138 views)
  Reply With Quote
Old 7th May 2012, 05:42 AM   #8
a.wayne is offline a.wayne  United States
Sin Bin
 
Join Date: May 2008
Location: Front Row Center
Quote:
Originally Posted by Conrad Hoffman View Post
0.01 mm is not achievable. Cumulative bearing slop probably exceeds that and it would take fancy lab equipment to get that close even if the mechanics were up to it. IMO, overhang numbers should be entirely ignored because most tone arms won't go over center to even measure it and very often the published numbers are simply wrong. Better to use a decent alignment template, mine or others, and be secure in the fact that if the cartridge meets the conditions of the template, the overhang is where it needs to be.
+10 and i can vouch your's work, been using it for awhile now ..
  Reply With Quote
Old 8th May 2012, 09:43 AM   #9
diyAudio Member
 
Join Date: Apr 2008
Blog Entries: 1
Default Record overhang

Hi, Yes 0.01mm is not achievable, I just slung that figure in the emphasize the importance of achieving the correct overhang. If you cannot achieve the correct overhang with the recommended spindle to arm length then move the arm, because overhang together with cartridge offset is the most important figure to get right.
I can assure that bearing play in any modern arm is a lot let than 0.01mm, and then again if you are using a uni-Pivot there is no bearing play at all
Yes setting correct overhang is quite difficult, because the spindle gets in the way of making the correct alignment. Some turntables allow the centre spindle to be removed to allow correct overhang to be set, the one that comes to mind is the TemaadAudio range. They have a precision removable brass centre pin, the only other way I know is to buy an expensive overhang gauge like Dr, Finckle (but I think to DIY people this would be sacrilege).


Max Distortion
0.5mm over : 1.0270
Correct : 0.6210
0.5mm under: 0.8360

If people set by eyeing down over the spindle they could be as much as 1.5mm out or more because the arm is acting in a arch and eye alignment is normally very, very poor. So you have to get the cartridge stylus down onto the record surface. Of cause then the problem is do you use a standard record or 200 grm as the record thickness will again change the desired result!! Such is life with playing record, so many variables but still great sound!!
Cheers Tabard
__________________
tabarddn
  Reply With Quote
Old 8th May 2012, 02:03 PM   #10
diyAudio Member
 
Join Date: Mar 2007
Location: Canandaigua, NY USA
Note my word "cumulative". That includes the platter bearing too. Just for fun, put a dial indicator on the edge of your platter and then rock the platter gently from each side. Pinning down the location of things to even 0.1 mm in 3-D space is harder than most people realize. Machinists think I'm nuts when I say even a good Bridgeport mill is only about a 0.003" (0.076mm) machine when talking about points in space. It's fun to track down error sources!

I agree about eyeball measurements. Most people can't get a cartridge body or stylus lined up with a reference nearly as well as they think they can. Given a good cross hair or better yet, a parallel pair of them, the eye can center and align things quite well. The longer the baseline the better. OTOH, if you think you can get a cartridge rotated to better than 1/4 degree, you're probably fooling your self; that's about .005" on a 1" baseline. If aligning to the stylus, the baseline is so short that the method is highly questionable. My odd shaped Ortofon is even harder to figure, so I usually tape vertical paper "gates" to the template to help.

The reason I did the arc template the way I did was because the one dimension you can usually pin down with sufficient accuracy is the spindle to arm pivot distance. Once you have that, the rest is easy- follow the arc, then rotate to a single grid. No iteration between two grids, which doubles any error.
__________________
I may be barking up the wrong tree, but at least I'm barking!

Last edited by Conrad Hoffman; 8th May 2012 at 02:09 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
FS: Calrad SV-16 16" Transcription Tonearm (Grace Oil Damped Tonearm) dnewma04 Swap Meet 1 24th November 2011 01:45 AM
Linear tracking tonearm vs. Pivoting tonearm Don Nebel Analogue Source 1 4th November 2007 11:49 PM
KT88 Minimum Mounting Distance Rob11966 Tubes / Valves 12 22nd October 2007 01:44 AM
DIY Tonearm Mounting Template ??? PlatterMatter Analogue Source 8 13th September 2007 07:01 AM
ADC LMF-2 tonearm mounting info Herb1 Analogue Source 12 8th October 2005 06:39 AM


New To Site? Need Help?

All times are GMT. The time now is 06:08 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2