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Tonearm recommendation

Hello all,
Recently procured a Feickert Blackbird w/ the Jelco 12 inch tonearm.
The table is really good, and its a keeper. The Jelco is also very good, but not as good as my Fidelity Research FR66s. So the Jelco will eventually hit Ebay, and the question remains do I keep the FR66s or sell that and buy something modern in the 5-6 K range. My only point of reference is my old JMW-10 on my Aries MK1, so I don't know how the FR66s would compare to a modern arm. So I'd like to rely on the collective knowledge and experience of this group for a recommendation.

Keep the FR66s, or go modern in the 5-6K range, say a Moerch DP8 or maybe an SME.

Any and all thoughts and opinions are of course much appreciated.

Cheers,      Crazy Bill
wrm0325
fleib
1,124 posts
 

The unipivot  has some advantages which are undeniable. Those advantages are reflected in the number of top performing unipivot designs.  One advantage is damping, a feature so highly touted in this thread. When SME came out with the model V, many design features were to control resonance. That included the tapered armtube and the fixed headshell. High end "contenders" in the '80s were Zeta and Alphason 100S - fixed headshells.  The advantage of a fixed headshell is to eliminate the physical boundary and its tendency to reflect vibrations back to the cartridge. This might not be an insurmountable advantage, but an advantage nonetheless.

By its nature, a fluid damped unipivot can easily be critically damped.  The potential to over or under damp a unipivot should not be considered a fault. Any arm can be set up improperly.

Most of the mechanical energy from the cartridge does not get converted to electricity. That's why top cart designs today use exotic materials and design features to dissipate energy. An elegant solution for excess mechanical vibrations from the cartridge is to dissipate down the armtube and convert to heat by the mass of the arm or plinth, or run it out of a foot.  The contention is, this is more easily accomplished by a unipivot; one clear path for vibrations to exit, while conventional bearings are a two way street.

The task of a tonearm seems impossible and contradictory, to be a stable platform while completely free to move laterally and vertically. Two dimensions of movement is an oversimplification. If an arm is moving laterally and vertically at the same time, the movement is angular or three dimensional. Are conventionally pivoted arms necessarily more detailed and exact?  I think performance defies that generalization.

Our Mexican friend likes to use the word distortion.  This is meaningless without supporting evidence. The Dynavector 507 II is a bi-axis design with intentionally high inertia laterally, and low vertically. This type of  inertia scheme is used by the DP8, apparently to good effect.

I'm not writing this in support of arms I haven't heard, but an arm designer shouldn't be expected to answer ignorant, unintelligible assertions.

Regards,

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rauliruegas
13,101 posts
 
Dear asvjerry: Nothing is perfect. Tangential, unipivots and pivoted non-unipivot tonearms designs has its own trade offs.

In theory tangential tonearms must be the best alternative but as always in audio when that theory goes to reality during playing that theory can't be confirmed because unfortunatelly the analog experience is way imperfect and theory comes and has foundation on perfect world.

That's why no single tangential arm I heard it can gives us the right bass range with the definition, precision, tightness and transparency that a well damped non-unipivot pivoted tonearm shows us.

As  I said the name of the game are those trade offs with tonearms designs and whcigh of those trade offs do lees harm to the cartridge needs for it performs at its best.

I'm for the well damped pivot tonearms and from this kind of design my choice is for the non unipivots.

The real and main subject here is: which are on each one of us the prefered trade offs?, sounds easy but way hard task we have.

regards and enjoy the music,
R.
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rauliruegas
13,101 posts
 
fleib: Unipivots works during playing in continuous desequilibrium, its bearing damping is not to really damp the whole tonearm but, mainly, trying to put at minimum that unstability during playing and that’s all.

What is your " sientist " relationship between that high inertia and high tonearm bearing friction in that tonearm design?

I own the 505 and I bougth it because I like it that design and looks " diferent " but the reality is that cartridge after cartridge, with diferents headshells and using Stevenson, L/B set up geometries I never achieved in no one of those top cartridges what those cartridges shows me in other tonearms and not only because is not a well damped tonearm, high bearing friction too but that high very high mass that looks the cartridge when it’s ridding the LP surface. I like the tonearm but not its overall performance, it does not really helps to the cartridge task.

It does not matters your " scientist " opinion unipivots are unstable during playback and till today no one can change it yet.

What did it some tonearm manufacturers to " hide " in some ways that critical stability problem?: choose better tonearm build materials as VPI and Duran gone with is blend material choice to damp in better way everykind of distortions but unstability is there does not disappears.

One point dissipate better that 2-3 way street: your opinion, not mine.

I remember carefully when appeared for the very first time the tip-toes by ( I think ) Mod Squad that works exactly as the unipivot bearing. All the high end community jump of hapiness and maybe there were no single audiophile that did not use it.
The tip-toes were designed to dissipate vibrations and convert it on other kind of energy and for the electronics or TT been stables with the 3 point configuration instead 4 footers.

I bought several sets of those tip toes and learned through many years that in reality are not in favor to " eliminate " those generated distortions but in some way amplify it or changed in other that still does harm the quality reproduction and because the feedback of those " vibrations " that pass trhough those tip toes never disappear the problem, are very uneffective but thank’s to tip toes todays we have all those and diferent kind of footers/dampers to use it in almost all our system links.

You can test in easy way what I’m saying ( and you don’t have to be a scientistific that certainly you are not. ). Take 3 tip toes and put under your CD player or TT or preamp or even your amps and see what happen against the damping " tools " you are using today and what you experienced is exactly what happen with unipivots on that regards. Additional the unipivots has that unstability " problem ".

Fleib " I’m inocent till the prosecutor can prove I’m guilty ". It’s not me who must prove anything. I made and make my posts and if you disagree with then you have to prove " I’m guilty " and certainly till now you showed and proved nothing at all.

Btw, do you know why you can’t do it and never will?.

Regards and enjoy the music,
R.
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