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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
nandric's avatar
nandric
4,086 posts
 

Dear Lew, If there was something wrong with lateral balance or

shape by FR-64 Raul would of course mention this many times

instead of ''damping problem''.  I made a considerable profit on

his recommended MM carts because those increased in price

as result. So I expected the opposite regarding the FR-64 because

I am still looking for the perfect sample. Alas this never happened.

You must be better in mathematics than I because everybody is

better in mathematics. But regarding the shape which I guess has

something to do with geometry (?) I am like this Serbian hunter

and chakster: ''still a goat !'' (aka S shape). I hope your FR-64 is

not mounted on one of your own made plinths? The only way I

know to adjust the lateral weight is to lift the front side for about

10-15 cm and then move the weight in the opposite direction in

which the arm moves ''on its own''. Till you get the arm in equilibrium.

If whatever moves ''on its own'' then there must be some ''will''

present. Why not by inanimate objects? How do some(?)

particles know where the other are (grin)?

lewm
13,174 posts
 
Thank you for that input, Raul.
And thanks for your response too, Nandric.
I don't have the FR64S owners manual.  So I assumed that the lateral weight had to stay mounted on its post; I therefore have shoved it up against the pivot as far as it will go, on the assumption that my turntable is level AND that even in the extreme position, the lateral weight is doing something greater than zero to compensate for the J-shape, assuming that is a good thing to do.
I too wonder whether Raul's opinion of the FR64S has damaged its value, but since I am enjoying mine, I really don't care very much.  I would not want to be one of those who recently paid a premium for the FR66S, however, where the asking prices are up around $6-7,000.  But this is no reason for Raul not to express his honest opinion, his right to which I do defend. Nor do I doubt Raul's sincerity.
dover
2,251 posts
 
rauliruegas
7,976 posts
07-04-2017 6:20am
Dear @lewm : You are rigth, it’s a J shapped design. Now, FR designed that lateral weigth balance mainly to compensate a non-perfectly leveled TT. Normally in the FR design that lateral weigth is not used if the TT is rigth on level. FR explained in its manual.
Raul, you are wrong.

The lateral balance weight should be set 5mm in from the end of the shaft on the arm pillar. This is the neutral position. It explains clearly in the manual ( page 6 ) that that if you adjust the vertical balance to 0 ( floating ), lift the turntable slightly and check whether the arm floats in or out then you adjust the balance in or out from that neutral position to compensate.

By reverse logic, if the arm mounting is perfectly level, then the weight should be at 5mm from the end of the shaft.

I have proven this by placing a gap checker under my arm board, and as expected when I tilt the arm board even a few micron the balance has to be adjusted in or out from that neutral position.

Furthermore when the arm is mounted perfectly level, and the Lateral Balance weight is 5mm in from the end of the shaft, the anti skate force required will be optimised.

It is disappointing that you would spend hours commenting on the merits of the Fidelity Research FR64S tonearm when you have clearly demonstrated that you do not understand how to set the FR64S up correctly. You hold yourself out to be an expert, when clearly you are not, and many folk who make the false assumption that that you are correct will be now setting their FR64’s up incorrectly (with the Lateral Balance removed ).

This is not the first time that you have made big mistakes in setting up your equipment, I previously highlighted to you that you had installed your Dynavector Karat Nova with the cartridge holder mounted on your arm upside down. Please find attached a video demonstrating where you went wrong on that occasion -
https://www.youtube.com/watch?v=x4o-imxZHS8


dover
2,251 posts
 
lewm
5,479 posts
07-04-2017 1:34pm
Thank you for that input, Raul.
And thanks for your response too, Nandric.
I don't have the FR64S owners manual. So I assumed that the lateral weight had to stay mounted on its post; I therefore have shoved it up against the pivot as far as it will go, on the assumption that my turntable is level AND that even in the extreme position, the lateral weight is doing something greater than zero to compensate for the J-shape, assuming that is a good thing to do.
Lewm,
Please read my previous post to addressed Raul.
Like Raul you clearly do not understand how to set up the FR64S correctly. The neutral position for the Lateral Balance weight is 5mm in from the end of the shaft. By "shoving the lateral weight up against the pivot as far as it will go" you are running the arm out of balance and your set up is compromised. In a good quality system this should be clearly audible. I would suggest you review the set up of your FR64S again to ensure that you are hearing the FR64S is it was intended to be used.  


nandric's avatar
nandric
4,086 posts
 

Dear Dover, ''there are many ways to skin a cat'' but this philosophy

does not apply for the lateral balance by FR-64. I have no idea why

this distance of 5mm is mentioned in the user manual. By using the

expression ''Apprrox 5 mm'' the manual is as ''exact'' as this

prescription. Not as curious as Raul's ''leveling the TT'' with the

lateral balance but it is difficult to judge which ''advice'' is worst.

BTW why should anyone use ''approximation'' when the correct

method is describd in the same manual? The possible exception

is our ''exceptional Lew'' because his plinths are exceptional qua

weight. Those can't be lifted (grin).

''The less the better or the heavier the better'' are both curious

rules. Those are probably ''deduced'' from Aristotelian ''essences''.

There is this principle called ''reduction of the complexity'' but this

has nothing to do with Aristotelian ''essences'' because he was

proven wrong by Galileo reg. physics and  by Frege reg. logic.

I also missed your opinion about shape. I like Lew very much but

I think that he and, more in partucular Raul, are/is wrong with

their ''J'' guess. Compare the (old) SME arms with FR-64 so

even blind people will see the difference. Looking at the back

side tube by FR-64 one can see the (slight) deviation to the

right seeing from above. To get the innicial balance between

the bearings the ''S'' shape is needed. The ''J'' kinds always

need lateral weight for this purpose. The later Ikeda arms can

obviously do without.  This to me means ''S'' shape,

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