Tone arm length

Hi @rauliruegas,

Long time ;-)

This exercise got me started as I’ve been handling quite a few vintage Japanese tonearms recently, and I’ve been wondering why they specify the same overhang for various effective lengths (15mm for both the 245mm FR 64, and 229mm Jelco for example).

Well, I still don’t know why they fixed the overhang, but when I modeled the FR64 and 9" Jelco, I realized that if you play with the offset angle, you can get reasonably good distortion characteristics with these specifications.

Of course, the problem is that you’ll have difficulty finding a protractor for their geometry (unless you have a factory protractor), which is why I tend to recommend mounting them for Baerwaald or Löfgren when possible ;-)

So down the rabbit hole I went, thinking of various scenarios to model.

After viewing the subtle differences, I don’t want to get into heated discussions about Baerwaald vs. Löfgren vs. Stevenson vs. (dare I say it?) Uni-DIN. Life is too short

Be well!

Thom

Probably many of us have experimented with Baerwald vs. Lofgren vs. Stevenson until we were so frustrated we wanted to take up a less challenging hobby...like chess. :-)  I suspect most of us concluded eventually that the difference between Baerwald and Lofgren was so difficult to detect that it becomes a coin toss for most practical purposes as to which to choose.  For new comers, unless you are very certain that you will only be listening to certain types of classical music (i.e. loud passages occurring near the inner grooves) , Stevenson is not as versatile and will result in greater tracking distortion over a broader arc of play for every record every day.  FWIW, I find Stevenson can be annoying particularly on piano, classical or otherwise.  As to the many excellent points made in this quite erudite discussion I find merit in the majority.  Yes it is true that a 12" arm that is properly set up will have less tracking error and distortion than a 9" arm.  Yes a 10" offers a useful compromise between the two.  My best current VPI HW-40 has a 10" arm.  Yes a 9" arm has lower mass all else equal and offers many advantages due to lower inertia.  What needs to be said is that all of these differences are subtle and any of these sizes works splendidly if set up correctly and if the user cares for the equipment properly.  In the end set up and care are at least as important as which equipment you choose.  One of my TTs is 40 years old this year (VPI HW-19) and the 9" SME Tonearm underwent a rebuild by SME Canada last year and the whole set up works and sounds very good indeed. 

Chiming in just to say I’ve been following the thread and learning, thank you.

I’m about to set up my 12” on as I have a new cart coming. 
 

I have some Wally Tools arriving soon.

Dear @thom_at_galibier_design  :  " I still don’t know why they fixed the overhang "

Overall the japanese vintage tonearm manufacturers really did not care to much about or had a misunderstood on the alignments subject.

I owned/own over 12 of those tonearms and after took in count that the specs can't " even " the Lögren alignments I just took the EL specification and set up with either of those Lögren alignments.

@macg19  : " 

I’ve been following the thread and learning, thank you.

I’m about to set up my 12” "

I can see not really " learning "  .

R.

The Japanese have throughout the 20th Century produced innovative designs in all areas of Technology, to the point where they were a World Leading Authorities.

Like all Business Models based on Technology there is the High Turnover Market and the Bespoke Market, Japan pretty much had both Markets sewn up and was proved to be very difficult to penetrate.

They did also contribute to a rise in Home Grown Markets cashing in on the Trends that Japan was so successful at bringing to the Mass Market Arena.

Questioning the design intent behind a range of Japanese TA's is futile as a activity, these designs are secure in their roles and very special to their owners or alternatively witnessed to be endlessly resurfacing as the option that proved to be better than many many others experienced.