Discuss The Viv Lab Rigid Arm

@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.

From a review by Roy Gregory

Cartridge setup and the RF7 CB: an extended exercise in patience

When it comes to cartridge alignment and tuning tonearms, it’s always a long, intricate and tedious process that demands considerable patience and benefits from considerable experience. In one respect, the RF7 CB and other Rigid Float 'arms are no different. However, they do bring a new level of frustration to the exercise, partly as a result of their mechanical execution and partly through their very nature.

For once, actually aligning the cartridge is simplicity itself. But challenges start when you try to set azimuth and tracking force. Despite ViV Lab’s claim that the pivot point of the bearing is fixed, there is a small amount of play in any given direction. When it comes to setting tracking force, moving the counterweights is enough to displace the 'arm (albeit very slightly) backward or forward. The movement is tiny, but it is enough to affect the downforce. Even cueing the 'arm will influence fore and aft location and hence the measurement of tracking weight. What this means is that those tiny adjustments in downforce are not repeatable -- because the displacement of the 'arm invalidates the resulting reading. Check the tracking force; raise the 'arm using the cueing lever; drop the 'arm again and you’ll get a different reading. If you are using a stylus balance that measures hundredths of a gram, the chances of getting any sort of consistent reading are almost nil. That wouldn’t be a problem except that the thread on the counterweights is coarse and the fit of the weights themselves is quite loose, so making small, angular adjustments of the multiple weight stack is also extremely difficult and imprecise. Now factor in the adjustment of azimuth, which suffers from the same geometrical variation and arm-height adjustment which, with no threaded adjuster or scale can be described as crude at best, while also risking displacement of the ‘arm’s base, and you have exactly the kind of moveable feast that makes setup a potential nightmare.

Question? Is the setup very frustrating? Can VTF be dialed in accurately and consistently?

Dear @rsf507  : I could think that you already know that the recording/playback overall process is full of imperfections and trade-offs.

Could you share which is your target doing that question? or maybe you already have the answer.

R.

@rauliruegas I thought it was a simple question. Since I’ve never used or seen a ViV arm and in the review Mr Gregory said it was difficult to get an accurate repeatable VTF, the question was aimed at those with direct experience, is getting repeatable and accurate VTF with this arm?

rsf, In my opinion, the pivot point should be fixed in space.  I do not view Roy Gregory's report that you cite as a good thing.

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.  Also, I disagree with the Viv website, if they say that the combination of zero headshell offset angle and underhung-ness has the net effect per se of reducing the skating force.  What it does do is create a smoother more linear transition in the magnitude of the skating force as the stylus traverses the LP surface.  Maybe this factor makes the high TAE at extremes of travel more benign than it would be in a conventional pivoted tonearm.  Just guessing.