2. analog
  3. 1332245803

Multiple arms, multiple cartridges and geometry?

I have read the debates regarding the benefits of different tonearm geometries......Lofgren A and B, Baerwald, Stevenson etc....and I appreciate the benefits of choosing where, on the vinyl record, one wishes to have the least spread of distortion.
I also have read where certain arms seem to perform better with one or other of these geometries?

I have two turntables with three different arms on each one and I have a total of over twenty five different cartridges.
Four of those arms have removable headshells and twenty of my cartridges are mounted on their own headshells ready for installation into any of those four tonearms.
How then.......can I have different geometries for each arm if I don't wish to re-align a cartridge within its headshell depending on the arm in which its installed?
Surely......I must select a single geometry for all my arms so that the cartridges fixed to their headshells....are truly interchangeable?
128x128halcro
dover
2,262 posts
 
Henry - for the arms you use that have detachable headshells, surely if you use a headshell that has slots, hence the ability to alter the overhang and alignment, then you can set each cartridge up and the only changeover issues would be tracking weight and VTA. I use to build easy VTA adjusters by tapping a metal block and using a fine thread screw to put under the arm lift. If you recorded the optimum for each cartridge/arm then it becomes easy to adjust.
Failing all this - buy 2 more TT's & enough arms and you can at least get 24 of your cartridges running simultaneously.
halcro's avatar
halcro OP
2,664 posts
 
Dover,
and the only changeover issues would be tracking weight and VTA.
That's what I thought and the principle I have been operating under?
However.....I fear that is not the case?
The effective lengths and overhangs being different for all my arms......means the arm geometry is not easily transferable?

Raul,
I agree that I need to accept the same geometrical alignment for all the arms I wish to use with detachable headshells......say Baerwald?
I can appreciate that I can adjust the P to S distance of each arm so that the 'Overhang' can be the same.......but I don't see how I can adjust the effective lengths between 222mm, 230mm or 295mm to be the same? :-(

Can you possible explain a bit more thoroughly?

Cheers
Henry
dougdeacon
3,338 posts
 
Nandric nailed it.

Get to work, and you might as well enter the S2IG (spindle-to-inner groove) dimension in a searchable database while you're at it.
nandric's avatar
nandric
4,086 posts
 
Dear Henry, Sorry, I overrated my Sliwowitz capacity. My
consideration was: the distance between the lead out
groove to the spindle differ by the most LP's. Depending from this distance Stivenson and Bearwald will give different inner 'O' points which means that one will be
more optimal than the other in (co) relation to the LP
you intend to play. You can estimate the distance or measure and then decide which tonearm (aka geometry) to use. Ie the geometry is primary about the records and only
'indirectly' about the tonearms.

Regards,
ecir38
155 posts
 
Halcro, thinking you may be able to work this backwards. ie allign MA505 to your chosen common allignment. Remove the headshell and put it on one of your other tonearms. Move P2S for that arm so that it follows the arc that the MA505 used then record the new P2S for future referance. Just a thought but not sure if this would work due to the differences of offset and overhang between the arms you use.
More to discover