Discuss The Viv Lab Rigid Arm

Personally I'm not interested in pursuing the Viv, but for all the naysayers, if you find the Viv concept so egregious, why are you still running any pivot arm.

A linear tracker has 0 tracking error, no skating forces to contend with, and if accurate alignment is your primary goal, then any arm other than a linear tracking, or tangential tracking, is a failure.

 

 

 

 

 

I hear no problem that I can relate to the extreme TAE, with my RS Labs RS-A1. " , fine with me.

Doesn't the RS Labs RS-A1 have a rotating headshell - therefore its like comparing apples and oranges with the Viv Lab

@intactaudio 

Thanks for the explanation - I did pick up that if the pivot directly above the stylus, then it cannot be self aligning. They claim that the pivoted headshell deals with needle chatter.

It is important to note that in both of the above cases the "design" of the underhung arm had the ability to absorb the energy caused by mistracking.  

If we accept that angular error causes mistracking, it seems entirely plausible that how the arm deals with and recovers from a less than ideal situation could play a large role in the sonic signature of the design.

This is of more concern to me - mistracking damages records. This would be a high price to deal with the vagaries of anti-skating, even though In my experience most folk apply too much anti-skate, resulting in offset cantilevers over time.

Most interestingly during an audio hiatus I ran a high compliance MM in a linear tracker for 10 years with the same stylus - cantilever was still dead straight despite the highish horizontal mass. Of course there are no skating forces with a linear tracker.

Is it possible to reverse the headshell 180 degrees with the RS and run a trailing pivoted headshell ?? Could be interesting.

 

@intactaudio 

That said, when eyeballing it I have always picked the slots that error on  trailing side since the thought of the stylus leading the pivot terrifies me. 

My gut feel is the opposite.

If the pivot trails the stylus tip the cantilever suspension joint is closer to the pivot point,

compared to

if the stylus tip trails the pivot point ( as you run it ), then the cantilever suspension point is further from the pivot point and therefore any directional correction driven from the stylus tracking the groove will result in a higher lateral force on the cantilever - more mass swinging around behind the pivot point too

 

@lewm 

There are 2 elements to the VIV Lab arm -

1. Zero offset headshell
2. Underhung geometry

What would be interesting would be to set the VIV Lab arm with 2 null points and straight headshell and compare that to the underhung geometry with straight headshell. Then we would get a more accurate picture of the "underhung" vs 2 null point impact on sound.

From my reading of the VIV Lab notes It would appear that the zero offset headshell has more impact on reducing skating forces than the underhung geometry.

From the posts thus far in this thread we have no idea of whether 1 or 2 above is the major factor in the VIV Lab sound.

 

 

@lewm 

Dover, I have to think about this some more, but off the top of my head, I do not think it is possible to set up an underhung tonearm so as to achieve two null points on the surface of an LP, no matter what you do with the headshell offset angle. 

You have misconstrued what I am suggesting.

I am suggesting keeping the headshell offset at 0 ( straight ) move the arm mounting point forward in order to set 2 null points. The 2 null points could be anything, for example 1/3 & 2/3 across the record. The 7 inch arm is probably not possible, but certainly the longer ones could be set up this way.

My gut feel is that the straight headshell has more impact than the "underhung" geometry.

With the "underhung" claimed by VIV I don't get it. If you look at their set up template their null point is in the middle of the record playing area, which means that irrespective of the "underhung" set up, skating forces are going positive and negative as the cartridge tracks across the record.

If they set the null at the end of the record, then the skating forces would always be in 1 direction only, and therefore much easier to control.

@intactaudio 

@lewm 

 

Earlier in this thread I mentioned setting the zero offset arm with 2 nulls.

What I really meant was as follows -

With a zero offset tonearm generally it is recommended to set a null point somewhere between the start and end of a typical LP.

You could set it halfway to minimise the maximum tracking angle distortion, or you could choose closer to the end of the playing area to minimise tracking angle distortion in the inner grooves for example.

What I surmise would be interesting to try would be to move the arm mounting point slightly forward so that the stylus is slightly forward of the single null point. You would then be able to reduce the maximum tracking angle distortion, the arm would be under and over hung, but you would still have the reduced skating force due to zero offset.

What say you.

 

 

 

 

 

@lewm

Its a bit hard without drawing a diagram -

If you draw a line from the spindle to the edge of the record.( call it line A )

Then choose a null point on that line

Now draw a line ( call it line B ) at 90 degrees to line A intersecting the null to the armboard or mounting point - so you now have a T.

Normally I assume you would position the arm mounting along that 90 degree line such that the stylus swings an arc where it touches the null, but both sides of the null are underhung.

What I am suggesting is now move the mount forward so that when the stylus is forward of the null point.

Now when the stylus swings through the arc it should intersect line A twice.

So now the arm starts off underhung, then crosses line A and goes to overhung, then crosses line A again and goes to underhung.

In this set up the maximum tracking error is reduced, but you would still have the advantage of no skating forces due to offset.

Alternative Explanation 2

Alternately if you take your existing Rigid Float move the arm across the record.

The stylus draws an arc.

Draw a line through the spindle that crosses that arc at one point.

Now with the stylus positioned at that point, move the arm mount forward along a line 90 degrees to that point..

Instead of 100% underhung either side of the null you will now have both under and overhung. You should if I have my head right have reduced the maximum tracking error - potentially you could halve it - by having a mix of underhand overhung instead of 100% underhung.

Hopefully you can follow this.

By the way here’s another example of a 0 SideForce arm. Fidelix have been around forever.

https://exclusive-audio.jp/en/products/0-sideforce

 

 

 

 

@lewm 

Yes underhung with respect to the spindle, but when I say under and over hung with respect to a line at tangent to the null point

Have a look at the diagram here  ( figure 2 ) -

https://theaudiobeatnik.com/review-viv-lab-rigid-float-ha-tonearm-part-1/

With the arm in the middle position on the diagram, the stylus is at a null.

Now if you move the arm mount forward so the stylus is now forward of that null point, you can reduce the tracking error at the inside and outside of the record, increase the tracking error through the middle, but overall reduce the absolute maximum tracking error.

 

 

I’ve been using a zero offset headshell for 38 years - the arm is a linear tracker.

Superior tracking, most accurate soundstage and lowest distortion of any tonearm I have heard or set up ( including several highly vaunted pivoted arms in my toolbox ) by a country mile.