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Curved and Straight Tonearms

Over the last 40 years I have owned 3 turntables. An entry level Dual from the '70's, a Denon DP-52F (which I still use in my office system) and a Rega P3-24 which I currently use in my main system. All of these turntables have had straight tonearms. I am planning on upgrading my Rega in the near future. Having started my research, I have noticed that some well reviewed turntables have curved 'arms. My question: What are the advantages/disadvantages of each, sonic or otherwise? Thanks for any input. 
ericsch
hiho
451 posts
 
What brf and Lewm said is correct... and now add helomech. 

No manufacturer would make a curved arm if the industry did not adopt the SME style headshell that has no offset angle. The ONLY reason to make a curved arm is to have the offset angle at the armwand since the headshell is a straight geometry. The SME 3 has detachable armwand instead of detachable headshell so they have to make the offset at the arm. Curved arm is a result of geometric necessity. If a curved arm sounds good, it is good not because is curved. The curved Alphason tonearm is made of one piece tube so they have to bend the arm to have the offset angle. Rega is also one piece but straight because the armtube is cast aluminum. Much of it is the result manufacturing process. Many curved arms with detachable headshell also have a side weight at one side of the bearing is because the uneven mass of curved arm needs to be balanced. Again, form follows function. Hey, I use curved arm with detachable headshell because I like having the option of changing out cartridges not because curved arm sounds better. 



nandric's avatar
nandric
3,263 posts
 

The J and S shape tonearms (need to) use the so called ''lateral

balance'' weight in order to get equal pressure on both horizontal

bearings. The J kind is difficult to balance while the S can be

balanced by lifting up the front side of the TT and then moving the

later weight till the arm reach equilibrium postion. From this it  

follows (?) that stright tonearms can't be in equilibrium position

because one side of the bearings  get more pressure than the

other.

helomech
766 posts
 
@nandric,

How does that apply to straight tonearms? Because of the slightest weight bias on one side of the cartridge end? 
nandric's avatar
nandric
3,263 posts
 

helomech, The Germans have this curious opinion: ''if theory and

practice coincide than both are probably false''. I own the  FR-64

designed by Ikeda san but also Ikeda 345 . Both have the same

'S' shape but the later is without the lateral weight. So, it seems,

Ikeda was not convinced about  (theoretical ?) advantage of this

''lateral weight'' by his previous arm.  

Your own ''bias'' is obvious because you used the expression

''the slightest weight bias''  with intention to belittle the issue(grin).

I would say ''it depends''  , among other, from the weight of

the headshell as well the cart. I own ''some'' which are above 30 g. 


lewm
6,770 posts
 
Nandric, I was just recently examining the shape of my FR64S.  Would you say it is more "J"-shaped than "S"-shaped?  That's what I concluded, J.  An S-shaped tonearm generally has two curves in it; the FR64S has one bend.  Either way, we know Raul hates it. He hates it with an intensity that seems inappropriate for an inanimate object.  I, for example, only hate certain politicians.  And yet, they pass for human.

How do you set the lateral weight?  I just have mine in close to the pivot.
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