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Fidelity Research cartridges

Any FR cartridge experts out there? Raul? Dertonarm? Syntax?
I have had an FR-7 which I bought a while ago. I tried it ever so briefly when I got it on an arm I now recognize as not being able to handle that weight (close, but no cigar). I just now pulled it out for kicks and after getting it adjusted with the big counterweight, I am VERY pleasantly surprised. Actually, I'm feeling kind of bubbly. It does not dig out the utmost in detail, but it just sounds very right.

Are there any other FR carts out there which are real steals if still in good condition? I know the MC-702 and the FR-1Mk2 and Mk3f by name, with good reps being assigned to the Mk3 and the MC-702. Given that the MC-702 and the FR-7 look quite similar, and they were offered at about the same time, what is different? And is the FR-7 just an integrated headshell version of the FR-1Mk3?
t_bone
chakster's avatar
chakster
6,144 posts
 
@bukanona

if tonearm is FR64 S version FR-7f will be better match.
in case of FR 64 fx both are good match.

What do you mean? Could you explain in details why do you think one FR tonearm is better for certain FR-7 series cartridge than another ?

For FR-7f or 7fz we must have optional W-250 counterweight for 64fx toneam for optimal performance in terms of tonearm effective mass. As you can see in this catalog the compliance of both FR-7f and FR-7fz is the same, tracking force is the same too.

The 64s has a higher effective mass and made of steel while the 64fx has lighter effective mass and with default (smaller) counterweight was designed for cartridges like PMC-3 for use on conventional headshell, or any other cartridges with higher compliance and lighter weight.

bukanona
174 posts
 
Question was about Benz and FR.

7f and 7fz looks the same from compliance point of view. 

Although do you believe in these compliance figures?

If to multiply compliance of given for 7f roughly by 2 in order to get 10 hz data we are getting 14 cu.


chakster's avatar
chakster
6,144 posts
 
ohh, i see
not sure why we discuss benz in Fidelity Research thread ? 
Completely different cartridge! 

Yes i do believe in the compliance figure given @100Hz 
It will be about 11 cu @ 10Hz which is pretty low compliance

nandric's avatar
nandric
4,086 posts
 
Confusion about effective mass by FR-64 s is caused by
assumption of ''given eff. mass''. But eff. mass depends from
the used headshell as well  the used counterweight. Not
to mention carts weight. 
bukanona
174 posts
 
S4 headshell with which FR 4S was sold weights 14,5 g (or it was supplied with 19 g headshell???)
So if roughly  to evaluate FR-64S + 7f :
35-14,5+30=50,5 eff mass, g
So if to go further and to compute desired  resfreq [Hz] 9 - we are getting if to use 11 cu --> 28,4 g  tonearm (Total)Effective Mass needed[gr] ; or roughly 35 grams tonearm eff mass needed in case of 8  desired  resfreq [Hz]

It seems that there are owners here in Audiogon of 64S + 7f or 7fz --> have you tested with test record lateral resonance frequency in your system? Could you please post here results?



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