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Time to choose: Baerwald, Lofgren, Stevenson ?

I’ve managed Dr.Feickert Analog Protractor for a decent price (build quality is superb, such a great tool).

Time to play with Baerwald, Lofgren, Stevenson alignments on my Luxman PD444.
Need advice from experienced used of the following arms:
Lustre GST 801
Victor UA-7045
Luxman TA-1
Reed 3P "12
Schick "12

Baerwald, Lofgren, Stevenson ? What do you like the most for these arms?
Manufacturers recommend Baerwald mostly. 

Dedicated "7 inch vinyl playback deserve Stevenson alternative, maybe?
Since it's a smaller format than normal "12 or "10 inch vinyl, it's like playin the last track's according to position of grooves on '7 inch (45 rpm) singles. RCA invented this format, i wonder which alignment did they used for radio broadcast studios.   

Thanks

chakster
fleib
1,124 posts
 

Lewm,

If the RS-A1 headshell doesn't rotate, then the only other unique feature the ViV brings to the table is the floating pivot. I'm not sure how significant this is, but I suspect you already have the better sounding arm. If the goal is to reduce torsional affects on the cantilever, your RS-A1 also does this in the vertical plane which might be more important than lateral. Vertical angular error is more noticeable and more readily heard, IMO. This might also apply to vertical torsion?

I've read a couple of reviews about the ViV and they both said the 7" arm sounds best. Conjecture was, this is due to reduced resonances. It's a little hard to imagine how 10° alignment error could sound better than a lesser value, but conventional wisdom doesn't seem to work here and it would be interesting to compare these two to the Grado Signature.  That one has vertical displacement and an SME type headshell with conventional alignment.


http://www.vinylengine.com/turntable_forum/gallery/image_page.php?album_id=1572&image_id=8766

Regards,


sampsa55
73 posts
 
Lewm:

I've been looking for that RS-A1 white paper. Do you have a link to it?


lewm
13,805 posts
 
Sampsa,
Somewhere I have or had a hard copy.  But I will also check my other computer to see if I have an e-copy.  It's one of those almost laughable translations from the Japanese, but one can make sense of the main points.  I see this problem with my son.  He thinks and dreams in Japanese. When he speaks to a Japanese person, he does not stumble for the correct words. He is a real scholar in this area. But if you ask him to translate a document from Japanese to English, I can tell that there is effort required, and it takes time.  In the RS-A1 white paper, you would see one claim that does not hold up; the paper states that "side force" (skating) is eliminated by the design, when of course it is not; it is only eliminated at the point of tangency to the groove.

Can you, in turn, point me to a review in which anyone compared two different versions of the Viv, so as to be able to say the 7-inch one was preferable?  I did not find that review in my search.

Fleib, Can you explain to me how the RS-A1 tonearm reduces or eliminates torsional effects on the cantilever in the vertical plane? I guess you are referring to its other structural oddity, which is that the unipivot bearing is above the plane in which the headshell operates.
sampsa55
73 posts
 
Lewm:
I recall seeing that white paper online, but have not been able to find it again. If you have a PDF, I'd appreciate it.

The RS-A1 unipivot it supposed to be positioned so that the cantilever and tonearm are parallel or ideally on the same straight line. Since not all cartridges have the same angle for the cantilever (I think they range from ~15 to ~22), this will be an approximation. The limited design info I've found doesn't mention torsion, but speaks of "downforce":
http://www.eifl.co.jp/index/export/rs-a1.html

When we usually talk about skating force, we assume that the cantilever is tangent to the groove and pulled along this tangent (only true at those null points naturally). Since the resulting force is at an angle to the line going from the stylus to the pivot, a sideways force results. If the cantilever is not tangent to the groove, the friction force would still be tangent to the groove and thus straight arms would also have a sideways force proportional to the angle between the stylus and the groove tangent.

I've seen reviews of the Viv Lab in The Ear, Stereo Times, and Audio Beat. All reviewed the 7" version and none of them complained about distortion. Audio Beat said they also had the 9" version, but just mentioned that the 7" and 9" sound different "and not in the ways you might predict". Also Audio Beat mentions that the order was the opposite you mentioned: The designer started with the very long version to reduce tracking distortion and then realized that the shorter ones sound better.

Fleib:
I'd appreciate links to those comparisons of Viv Lab versions too.
fleib
1,124 posts
 

Lewm, Sampsa,

The only reason to elevate the pivot is to have the cantilever aimed there vertically. It's not beneficial for tracking like an underhung counterweight. That's the only plane where that happens on the Grado arm. The VE photo was supplied by Werner and the arm is said to sound great.

There was no direct comparison of the three ViV arms. It was mentioned in Stereo Times that the shortest version reduced resonances. There was another review/comparison which I can not find now. It stated the 7" sounds better - for the same reason.

Regards,

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