Tonearm Geometry and Setup


While this subject matter seems to be of 'crucial importance' for our hobby our discussion about this issue is fragmentary and split over different threads in our forum. As if we are talking about some 'abandoned child' that nobody wants. I thought that this 'child' needs its 'own home' in metaphorical sense or its own thread in the
usual sense. While tonearm geometry seems to be very 'simple' in mathematical sense there are many unresolved questions in the actual sence.
My question for the start of this thread is:
'why are we not free to choose the zero points on the record radius independant of the tonearm used?'

Regards,
128x128nandric

Showing 7 responses by nandric

Dear John, Thanks for the x time . 'As skating force is
always there...I feel comfortable that the forces on the stylus are equilized AS BEST THEY CAN BE'. You are of course refering to the fact that (anti)skate force is variable across the LP radius. To my knowledge only Sony
provided for a 'varible force' depending on the radius(?).
There are also some claims for the Triplanar (which I own) reg.
variable skate force but I can't see that, so to speak.
Is the variable anti-skate in this sense so difficult to design? The ususal 'solution' is just a (small)'hang'- weight.

Regards,
I am of course not (pre)supposed to answer my own question
but considering Stanwals comment I need to put my question more clearly. The context is this: 'we', or at least I, got the impression that I can choose the 'zero points' depending on which part of the LP I want the least distortion. Baerwald is about the best solution for the whole record radius (aka 'the average') while the other provide better solution for specific part(s) of the record. Ie Stanwals 'least destortion' in general will not
do. This thread as well as the question of 'choice' is caused by some remarks by Dertonarm in the 'Copernican thread'.

Regards,
Dear John, If the designer is free to choose between Lofgren and non-Lofgren geometry than he obviously will do this according to his own preference or assumptions regarding the (potential) customer.But this way he already preselected the 'optimal adjustment' for the customer?
Kessler&Pisha stated in the context of 'Overhang' that many
Japanese designers 'overlooked' the dependance from or correlation with the eff. lenght. So, for exapmle, Dyna 505 has 15mm overhang while 17.164 should be optimal. Ie
the eff. lenght corresponding with 15mm overhang is 274mm
(10.787 in.). This lenght will not fit the turntables disigned for 9" tonearm ( Tonearm geometry and setup; Audio, January 1980). My 'intuition' is : you can't have
it both ways; the choice for the designer as well as the choice for the user. Ie the choice of the designer limits the choice of the user. As far as I know our choice for
Bearwald means the least distortion for the whole record
radius (aka 'avarage') while Stevenson means the least distortion near the lead out 'part'.
This means to me 'one way or the other' and this precludes
our 'free choice' or at least limits our choice. Otherwise
I am not able to make any sense of 'different tonearm geometry'.

Regards,


.
For those who think to be good in math but also think to
have good nerve there is an article from Stereophile by
Keith Howard on the net: ARC ANGELS; Optimizing Tonearm Geometry. Look for : tonearm geometry.
I myself should keep my promisse to myself made after
my high school : 'never ever mess with math '.

Regards,
Dear Gordon, Thanks for your explanation. In some earlier
thread you refered to my 'point' about different tonearms
each of them adjusted to the 'needs' of the LP's in our
possession. Your arguments in this thread assume just one
tonearm in correlation to the 'best' possible adjustment.
I have no intention whatever to spare you but on the contrary will try to get as much info from you as I can . We are allowed to ask questions in this forum I think.
My first is reg. those max distortions. You forget to mention how 'bad' 1% or more is. Then there are many of us with two or more tonearms. My quess is that they all are adjusted in the same way. Ie with the same geometry. From what I think that I can deduce from your arguments we should adjust them differently. Dependig on the records we
own.

Kind regards,
Dear John, There is this hilarious English phrase for the
German tourist: 'Don't mention the war!'
Well you deed mention the anti-skate...The most controversial subject in our forum according to my knowledge. My 'Solomon' solution is 'in between'. I use my test-records to get some idea about tracking ability but never push above 60 micron. Ie if there is no 'buzz' from the R.channel at 60 micron I live the anti-skate 'there'. I come a warning from Van den Hul across not to try to get,say, 80 microns which the cart can 'perform' because
one need to increase the anti-skate to get this 'result'.
Something like : better no anti-skate at all than to much.
What is your method?

Kind regards,