Spin Doctor #17: Paging Dr. Löfgren, ViV Laboratory's Rigid Float 9ha tonearm Page 2

The result is what's known as an underhung arm, where the stylus plays the record in an arc that doesn't reach the record's center. Instead of two null points, an underhung arm can only have one, with tracking angle error that increases to its sides. ViV places the null point about two-thirds of the way into the record, 90mm from the spindle. This design choice biases the tracking angle error so it's greatest at the start of the side, where the linear speed is highest, and the groove modulations are more spread out. In return, you get more accurate tracking at the much tougher-to-play inner grooves. The maximum tracking angle error is about 10° at the start of the side compared to about 2° with a typical 9" overhung tonearm. While that may look bad on paper, how bad is it when you're playing a record?

If the ViV tonearm's pure straight approach was the only thing that sets it apart from more conventional designs, that by itself would make it a pretty radical design, but the Rigid Float's uniqueness runs much deeper. The name—"Rigid Float"—describes the arm's bearing. ViV Labs is kind of secretive about how it's built. My understanding is that there is a ball on the moving part of the arm that sits in a cup-shaped magnet. Between them is a layer of magnetic oil called ferrofluid, which levitates the ball slightly while centering it magnetically. So in some ways it is similar to a unipivot. With the thick layer of oil acting as an interface, the bearing's friction is vanishingly low, moving smoothly and freely with the slightest touch. The oil also acts as a vibration damper, tamping down energy transferred from the cartridge through the armtube.

Speaking of armtubes, the Rigid Float is available in two versions. The 9" HA-9 ($4500 as reviewed) has an aluminum armtube. The CB-9 with a carbon armtube costs an extra $2000. The HA and CB arms are also available in 7" and 13" versions. Seven inches would be extremely short for a pivoted design, but it matters less for a pure straight arm. The 7" version has a spindle-to-pivot distance of 227mm, which is close to that of a typical 9" arm, while the HA-9 sits at 274mm, more like a normal 12" arm. This means that the 7" version will fit on most turntables designed for a 9" arm, while the 9" and 13" arms require more space.

Note that I never used the word "mount" in describing the ViV Rigid Float. That's because you don't actually mount these arms to the turntable; they just sit there on their own base, either on the plinth or off to the side. At more than 4lb, the Rigid Float is a true heavyweight; it will stay wherever you put it. That weight means, however, that it won't work well on top of the plinth of a softly suspended turntable like a Linn LP12. Furthermore, the surface the arm is placed on needs to be between about 2" and 2.5" below the platter surface in order for the arm height to be within a usable range for VTA adjustment. On many turntables—probably most—the height difference between the surface of the plinth and the platter is smaller than that. There's a solution to both of these problems: a height-adjustable platform offered by Sierra Sound, ViV's US importer, called the NAB-1. The NAB-1 allows a Rigid Float arm of appropriate length to be placed off-plinth at an appropriate height.

I used the HA-9 arm with my Brinkmann La Grange turntable. I started off by placing the arm directly on the turntable's round arm pod. After adjusting the null point correctly, the Rigid Float's base was uncomfortably close to the edge, so I pressed the NAB-1 platform into service, sitting it directly on the Zoethecus Z-Slab that supports the Brinkmann and using its longest adjustable spikes to raise the arm to the appropriate height.

Accurate leveling is critical with the Rigid Float; it has a very sensitive level built into the top of the arm, which makes dialing it in with the three spikes supporting the NAB-1 quite easy.

The Rigid Float uses the popular "SME-type" H-4 headshell connector. However, the ViV "Nelson Hold" headshell that comes with the arm is far from conventional. Instead of having a large, flat cartridge mounting area, the Nelson Hold has a long, fingerlike backbone onto which a cartridge mounting bracket is attached. This backbone extends beyond the cartridge position to form a finger lift for manual record cueing. In the center of the bracket is a knurled knob ViV calls the press screw, which can be tightened down to apply pressure to the top of the cartridge immediately above its generator. By adjusting the tightness of the press screw, you can fine-tune the resonant behavior of the cartridge body.

The press screw is one of several tweaky fine-tuning features of the arm. A pair of elastomer damping rings fitted around the armtube provide another opportunity for tuning; they can be moved along the arm's length to apply vibration damping in specific areas of the tube. The armtube can also be rotated on its own axis to adjust the cartridge for azimuth. In a straight arm, in contrast to an armtube with an offset headshell, rotating the armtube will not cause a change in the stylus rake angle.

I auditioned the Rigid Float using a wide range of cartridges including a Benz Micro LP-S, a Shure V-15 Type V MR, a Lyra Atlas λ Lambda—even a vintage Ortofon SPU. The Lyra seemed especially appropriate considering that designer Jonathan Carr's comments were the original incentive for this review.

When I set up cartridges for my clients, I take great care to align them for the lowest possible distortion, so I really didn't know what to expect as I lowered the Atlas to play "I've Seen That Face Before (Libertango)" from the Grace Jones album Nightclubbing (Island ILPS 9624). Would there be obvious distortion and mistracking? Would the Lyra's sharp-edged line-contact stylus carve slivers of vinyl from the grooves? Happily, the answer to both of those questions is an emphatic no! Instead, I heard clear, dynamic sound, with excellent, detailed bass and a well-focused soundstage. Grace's vocals stood forward, in clear relief from the band, while Robbie Shakespeare's bass bounced along cleanly with plenty of power and extension. Uziah Thompson's clackity-clack percussion line had excellent definition and bite.

After the arm passed the Grace Jones test, I went out of my way to find the arm's Achilles' heel, playing some of my favorite torture tracks for tracking, such as Montserrat Caballé singing Verdi's Aida (EMI Electrola 1C 195-02 548/50), and Rondo Lapponico (Proprius PROP 7797), a recording of an unaccompanied Swedish choir. Neither Caballé nor the Swedes could evoke any kind of cartridge misbehavior. I eventually heard some obvious coarseness and mistracking when I played "Blue Bayou" from Linda Ronstadt's Simple Dreams (Asylum 6E 104), when Linda started to belt out the line "I'm going back some day, come what may to Blue Bayou." This track is a challenge for any cartridge and arm, and as the first song on side 2 of the album, it sits right where the tracking angle error on the ViV is at its most egregious. I don't consider that a fail.

Once I stopped searching for problems and just played some records, the strengths of the Rigid Float became much clearer. Dynamics and what the late Hiroyasu Kondo of Audio Note Japan would describe as "non-mechanical sound" are what the Rigid Float revels in. This is best heard using relatively simple recordings like Hugh Lawson's Colour (Soul Note SN 1052), a jazz-trio record. On "The Tinkler," Lawson's piano has a wonderfully natural attack and a rich sense of harmonic color (colour?) that highlight Lawson's fine touch. The sound of Calvin Hill's bass was equally impressive, with plenty of grunt when he dipped into his lower register. Each note remained precise and tuneful.

The ViV Rigid Float tonearm is one of the most unusual tonearm designs I've encountered, violating many rules of tonearm design that I had long assumed were sacrosanct. It makes a compelling argument for its alternative approach, and it has some practical advantages not found on other arms. These include the ability to switch between cartridges easily and to quickly add or remove it from a turntable with no need for physical mounting.

The ViV Rigid Float is a tinkerer's delight that presents music in a wonderfully natural, unfussy way.

ARTICLE CONTENTS

COMMENTS
orfeo_monteverdi's picture

"Over the years, there have been many linear tracking tonearms that do this with varying degrees of success, including models from Clearaudio, Eminent Technology, Goldmund, and Bergmann"

Not to be forgotten: Polish manufacturer Pre-Audio offers what could be the most affordable silent air-bearing linear tracking turntables on Earth.

I could not afford the big names. So I bought a $4850 Pre-Audio DE1800. Magnetic platter bearing, granite base, air-bearing linear tracking arm, silent compressor.
Excellent value for money. I couldn't be more happy.
(carefully choose a matching cartridge and phono preamp though, as that deck can sound extremely detailed)

DE1800

Glotz's picture

I need to hear and see this!

Doug in CT's picture

Dear Michael -
You write that "...the ViV Labs arm simply gets rid of the skating force by eliminating the offset angle and making the arm straight."
Unfortunately, a straight pivoted arm will skate just like a pivoted arm with offset, because it's not the offset that causes skating. J.M. Boisclair and Andrzej Malewicz of WAM Engineering demonstrated this convincingly several years ago.
Michael Fremer gave a summary of their analysis, with links to videos that help visualize the concepts, in a 2020 article for Analog Planet. It's still available at (https://www.analogplanet.com/content/everything-you-know-about-skating-wrong).
In short, pivoted arms exhibit skating --both inward at the beginning of a side and outward toward the end of the side-- because they are essentially similar to a pendulum swinging back and forth across the low point of an arc. Instead of gravity being the force that pulls the arm/pendulum back toward the low point, it is the surface drag of the vinyl.
Skating also occurs on blank record sides, in the same way, so it is likewise unrelated to groove modulations or other such features.
One further point: I haven't watched the talk by Jonathan Carr of Lyra that you mention, but I doubt that he envisioned tracking error of 10% (as with the ViV) when he said that minimizing tracking error is less important than other aspects of cartridge setup. Any halfway-decently aligned cartridge will have tracking error no higher than 4% and probably less than that. That level of error is in fact less than the typical sample-to-variance between cartridges from a single manufacturer.

Trenton Carr's picture

"so the ViV Labs arm simply gets rid of the skating force by eliminating the offset angle and making the arm straight."

So wrong, it's funny.

Skating force is a geometry problem, and this tonearm has it.

SF is a result of effective length tangent to groove error, not over/underhang or headshell offset.

I'm flabbergasted a designer would lead with that in marketing.

Show the behaviour on a blank disc and let the results speak for themselves. My bet is it will settle 2/3 in. If it is not stable at every drop point, it skates. Easy to prove right or wrong, yet no designer will show that.

sierrasound's picture

https://youtu.be/Jzd0jNgf_q8

You're right that the skating isn't at zero across the face of the record. Only a linear arm could achieve that. But the skating force is miniscule compared to an arm with overhang, which leads to better lateral stability.

Trenton Carr's picture

In your video, you mention the higher friction due to groove modulation, however, the difference in magnitude is minimal. You can FEM simulate this minor difference with a textured surface corresponding to the information in the groove.
Your video effectively demonstrates that the arm skates, which is a crucial point and contradicts the text of the article.

A major issue with your demonstration is that the coefficient of friction is only one component of skate force. Increasing the friction when the arm is already at the tangent to groove point, where there is no skate force, will result in no skate force. Even if you ran your stylus over a brick at that point, there would still be no skate force. For transparency, you should have placed the sticky note near the start or end of the groove and observed the stylus behaviour, which would likely be very similar to that of the Technics.

In fact, if you install the cartridge on the Technics with a similar tangent to groove position and ran it over the same sticky note, the behaviour would be identical, and it could also claim AS is not required.

A no-skate tonearm is impossible with a fixed effective length pivoting tonearm, and you can make the Technics behave exactly the same.

All high-end audio products suffer from perception and bias issues, even if an effect from an underlying truth cannot be perceived, it will still have an effect on the purchase decision. I build and design pivoting tangential tonearms for a singular customer, and although it is not perfect, it is still loved.

Please do not take this as reason that no one could love and enjoy your tonearm.

sierrasound's picture

However, I don't see a big contradiction between your points and what is illustrated in my video. We are not claiming the ViV Lab arm achieves zero skating force along the entire record surface. We are claiming that it is zero at the null point, and the rest of the time it is so diminished as to become insignificant, to the point where a counteracting anti-skate force is not required.

One point I disagree with though, you said "you should have placed the sticky note near the start or end of the groove and observed the stylus behaviour, which would likely be very similar to that of the Technics"

If I did this on the ViV arm, the skating force would become temporarily increased from the friction and move toward the null point faster. However it would not behave like the Technics, which oscillates laterally as the skating force constantly fights against the anti-skating force. The ViV would simply settle toward the null point and stay there.

A traditional arm with overhang and anti-skate encounters 2 opposing lateral forces simultaneously, skating and anti-skating. They fight each other constantly as friction varies and one force overtakes the other.

With the Rigid Float there can only ever be skating force in one direction- toward the null point. And this force is tiny compared to an arm with a big overhang. So that's where we feel that this design has an advantage.

Thanks for engaging and discussing. You've obviously given the issue a lot of thought and I hope our discussion, regardless if we agree or not, will be enlightening for those who read it.

Trenton Carr's picture

Apologies, I did not get that, "We are claiming that it is zero at the null point, and the rest of the time it is so diminished as to become insignificant, to the point where a counteracting anti-skate force is not required." from the article.
And every tonearm with a tangent to groove point, does not require AS, as you claim then.

Also, the Technics should not be oscillating as the spring acts as a constant load and there is no fight between the 2 forces, if it's oscillating, there is a compliance problem. The force you think is making the Technics oscillate is this big --> 0.0009N, yep, small enough to be sunk by the tonearm's inertia from the effective weight, counterweight and the compliance in the stylus. I suspect you are overestimating the effect the degree of modulation the groove has on the skate force. These forces are tiny.

"The ViV would simply settle toward the null point and stay there."
True for all tonearms with a tangent to groove point, and all the music is not at that point as well as being locked in groove.

"With the Rigid Float there can only ever be skating force in one direction- toward the null point. And this force is tiny compared to an arm with a big overhang. So that's where we feel that this design has an advantage."
You can set up any tonearm the same way, and it will behave the same, and if that works for you, Great!

Good Luck!
I wish for you all the best for your tonearm, I want more tonearms on the market, not less.

Glotz's picture

I wanted to see the tonearm in situ, but from a distance.

Love the design approach. This arm is very intriguing and thanks for this comprehensive look and the column once again.

Oh, and the proof is in the listening- as you found!

sierrasound's picture

I uploaded a few more photos showing the arm's complete form:

www.sierrasound.net/downloads

I have some photos of the arm in action on different turntables as well, email me if you'd like to see them.

mike@sierrasound.net

Glotz's picture

Thanks, Mike!

Ortofan's picture

... Yamaha GT-5000 turntable, which has a straight tonearm.
He can query Yamaha about their rationale for excluding anti-skate compensation.

https://usa.yamaha.com/products/audio_visual/hifi_components/gt-5000/index.html

https://www.hifinews.com/content/yamaha-gt-5000-turntable

directdriver's picture

https://youtu.be/fQeut0__a_4?t=1110

sierrasound's picture

and thanks to all who read it. I love this tonearm and everyone who hears it has nothing but good things to say, and I'm glad Mike feels the same.

I see in the comments that there is still some skepticism and misunderstanding, so I made a video that will hopefully clear up a lot of questions about skating, anti-skate, and the pros and cons of traditional geometry. Here is the link:

https://youtu.be/Jzd0jNgf_q8

There is much more to this arm than the unconventional geometry. The ferro-fluid bearing is a totally unique element and creates a near-zero amount of friction while still providing excellent energy damping. This, along with the free-standing nature of the arm, has as much to do with the tonearm's performance than the geometry. And by the way, the sound is clear as a bell, you will not hear distortion even if you think you should...

Finally, for those who asked for more pictures, they have been uploaded to our website:

www.sierrasound.net/downloads

Thanks again to all who have taken the time to learn about this special tonearm.

Sincerely,

Michael Fajen
President, Sierra Sound

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