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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
Post removed 
fleib
1,124 posts
 

Dover, Interesting comment. The straight zero offset arms available today address lateral torsional forces.  The ViV Rigid Float requires little or no antiskate as a result of this. Skating force is increased by cart offset, that is lateral cantilever angular difference between pointing at the pivot and pointing at offset angle. There is still skating because the cantilever is tangent to the groove at only one null point on an underhung arm, but it's said to be insignificant.

The only arm I've heard of that addressed lateral and vertical torsion is RS Labs. That one had the pivot elevated so the zero lateral offset cantilever would also approximately be vertical zero offset.

The trade off with alignment error is significant, but reviewers say it's worth the trade. Ironically, they also say the shorter version sounds better. This is supposed to be because reduction of length also reduces arm resonances, or something like that. It's conjecture but makes sense. 

My skepticism with distortion figures and alignment error correlations isn't based on these arms. There is necessarily a phase difference between channels with lack of tangency, but it seems to me any other distortion would be cantilever and tip dependent.

Regards,

Ag insider logo xs@2x
rauliruegas
13,101 posts
 
fleib: """ When you adopt a different alignment you're also changing effective length ... """

according with that sentence a tonearm designer first needs to know the pivot to spindle distance to determine the effective length on his tonearm design?

You said that I have to forget Löfgren papers but makes no sense to me because there is the overall foundation on tonearm alignment and from there comes all the know type of alignments as: Baerwald, Bauer, Pisha, Stevenson, etc..

So, please tell me why me or any one must do that?. Don't put examples of nothing and please give a specific answer because through this thread you never give a specific answer with an explanation of why: yes or why: not.

You are reluctant one and again to avoid the Löfgren papers and just post nothing that makes reference to it:

which are your reasons not to do it? what's wrong down there?

The 3 calculations on 3 different type of alignments ( through Löfgren original papers. ) I posted showed that on each calculation the PtS distance was a variable and different on each type of aligment.

In the Löfgren his equations ( and all the other know alignments posted here: B, P, B, S. ) starts with a knowed L ( effective length ) and from here comes all the alignment variables like the PtS one that in there comes from here:

M = L - d    , where L is the knowed ( fix. ) effective length, d the calculated overhang and M the PtS distance.

Please don't just tell me that I'm wrong. Tell me why, give any explanation. This is not a contest as many gentlemans here I want to learn and if you are right then: good for all of us. This is all about.

Regards and enjoy the music,
R.

Btw, forgeret about that 505. It's not the main subject in what we are discussing.
I repeat don't put examples just an explanation and please don't try ( again ) to change the subject taking a different " road ". Stay in the road!

Btw, I'm using the IEC ( not DIN. ) standard for the calculations in the original equations and through it the second solution in Stevenson ( first solution is similar as Löfgren A. ) calculated this null points:

60.325 and 117.417  , not the ones by VE not even if I choose DIN standard. Remember that accuracy is the name of the game: cero tolerance, but the point is that of these null points but about that effective length subject.


There are many internet calculators that as VE ones does not stay in focus.

The original equations are simple ones and by algebra we can do whatever we want ( I already said it 3-4 times in the thread. ).

If we want the PtS distance fixed then we can do it or if we want that the overhang stay the same with different alignments we can do it.
That's what shows all those calculators and create several misunderstood like the fleib one.

Fleib, I already did my job years ago because I had that misunderstood too. 
Now you need to do your job too just from the begining with the foundation of all this subject: Löfgren explanation and equations and I'm sure you will understand it or can confirm your point.

Repeat, forgeret about manipulations of those equations or new dedicated  alignments because no one can hear the level distortions changes in an accurate alignment set up.




lewm
13,148 posts
 
To re-enforce what Dover said regarding the DV tonearms, I had the experience of mounting a cartridge in my DV505 using Baerwald, which requires the cartridge to be twisted inward with respect to the long axis of the headshell.  It was surprising to me that this did not sound good at all, using a cartridge with which I was quite familiar, and I hypothesized that having the cantilever arc at an angle to the vertical arc described by the arm wand was a possible cause of the distortion I heard.  When I re-aligned the same cartridge using Stevenson or the DV recommended parameters, all was well.  This is what I call circumstantial evidence, but it makes some sense.  And I draw the conclusion that it is wisest to use the geometry for which the tonearm was designed, not necessarily one's own preferred geometry, when using typical pivoted tonearms with offset headshells and stylus overhang of the spindle.

I own an RS-A1. It is quite a weird gadget, not easy to set up but at the same time rather uncritical of P2S distance.  It does sound surprisingly excellent with a wide variety of cartridges.

fleib
1,124 posts
 

Raul, My job is being a consultant to you? This is news to me, am I on the payroll? Maybe a flat fee for consultation, or maybe I misunderstand. I thought this thread is about high quality arms around $6K or less. It looks like all the DV arms have the same geometry and the 507 may look a little weird, but I don't care about that.

I thought I was your geometry teacher - remedial 101. I guess not because you're assigning the curriculum.  This is confusing, and to be honest, Griffithds would be a better consultant/teacher. He comes highly recommended and has experience in the aerospace industry. He's practically a rocket scientist. I'm quite sure he's forgotten more than I know about math, the problem is how much does he remember?  Remember his post admitting to brain flatulence? Not much to worry about on that score though, he can consult from home.

You know the bit about feeding the hungry - teach someone to farm and he can grow his own, or something like that?  That was my teaching plan.  Know any algebra? You're supposed to pass algebra before you take geometry. How can you solve an equation without algebra? I think you just push buttons without understanding and want someone to tell you which buttons to push?  Know what an equivalency is - 2 sides of an equation? L = MD + OH   L = 10" = 254mm.

254mm = pivot to spindle + overhang. L is your constant and you need 2 numbers that add to 254 for the other side of the equation. To find those numbers for any standard alignment go back to VE calculator and put in 254 for effective length. If that doesn't work find a 254mm arm in the database and click on the nulls. That will give the other numbers.

That's the best I can do. My specialty is solid geometry and my brain is farting like crazy. They told me I was filling in for Professor Timeltel. I thought he was an English Lit prof. I think I was conned. Did Timeltel retire? I don't know what's going on, but Griffithds is your man.

Regards,

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