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Fidelity Research FR-64x

 Fidelity Research FR-64x.....(with silver wire ).  Is this arm still considered  viable today ?

offnon57
nandric's avatar
nandric
3,263 posts
 

@sampsa55 , Thanks for enriching my tonearm collection with

FR-64 fx. I own both 64 S kinds in the sense of silver and copper

wire. I also own Ikeda 345 . Alas not FR64 fx. But I need to start with

 my Sumiko 800 (''the arm''). The arm is designed by physicist David

Fletcher and (hand) made by his master machinist Demian Davidson

from 160 parts. The curious things are: The arm looks like a Breuer

twin but while Breuer refused to make any additional counterweight

for his customers Fletcher designed 6 different counterweights for

his Sumiko. The reason being to provide the right weight for the

carts from 6- till 25 g. This way each individual cart could be adjusted

such that the counterweight would be as near as possible to the

pivot. This seems to be relevant for both: arm mass as well for

the inertia. Lew is very fond about Newton while ''mechanics'' is the

 best established  physical science. As lawyer I need to pretend

to know everything otherwise nobody would be willing to hire me.

In this forum and ''among friends'' I don't need to pretend. So I

hope ''our Lew'' will explain ''the mechanics''. This would be more

in accordance with his eloquence then his modest contribution

about silver oxide versus copper kind (grin).

sampsa55
71 posts
 
@nandric Sorry! I meant @chakster. He acquired an FR64fx to use with his FR7 & SPU.

And regarding the mechanics, since you are adjusting both the distance and the mass so that they balance exactly the same thing on the other side, it's not obvious to me why anything important would really be different. If you're moving the same mass to be closer, then you are clearly having an effect, but then you would also need to adjust the mass on the cartridge side to remain in balance. But I'd be happy to be educated on this.


dover
1,165 posts
 
@sampsa55 
For a point mass the moment of inertia I = mass x Radius ( distance from pivot ) squared. The further you push a weight out the moment of inertia increases disproportionately ( by the distance squared ).

sampsa55
71 posts
 
@dover 
Since the torque created by the mass of the cartridge that you're trying to balance is force x distance, a larger counterweight closer to the pivot can have the same torque but lower moment of inertia. Ok. Thanks.


chakster's avatar
chakster
2,482 posts
 
The aesthetics is very important for me, i can’t ignore it, the SME 309 and SME V are the ugliest tonearms in my opinion, every turntable with this arms looks awful. Well, i’m talking about the design, but not the quality of those arm, i’m sure they are high quality tonearms, but i love vintage tonearms not only because they are good, but also because i appretiate design of those classic gear. For the same reason i hate most of the modern turntables and most of the modern tonearms. I can’t deal with expensive stuff if i don’t like the design (color, shape etc). It is not important for everyone, but for me it is very important. Even the old SME are not my kind of tonearms, but they are closer to what i like aesthetically (except the one SME made for high compliance carts).

Yes, my interest in FR64fx is mainly for Fidelity-Research cartridges such as FR-7f and PMC-3 (and also the best SPU Royal with Replican 100 stylus which i am selling).

For "normal" cartridges i’m happy with my Reed 3p "12 Cocobolo - this tonearm is hard to beat, but it’s not good idea to swap the cartridges every week.

The Technics EPA-100mk2 is another one from my arsenal, but damn, it’s impossible to mount it on Luxman PD-444, the vta on the fly mechanism makes this arm too high in the lowest possible position. So i will have to use it on SP-10mkII or on Victor TT-101 later on. Maybe i need tonearm pod.


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