Discuss The Viv Lab Rigid Arm

Dear @intactaudio : Here are your main posts to me in even you talk about calculation where what I posted were all about LÖfgren A alignment calculations.

 

It’s really weird that in no other of your posts but only in the last one mentioned about " null points in LP surface existence ". Read carefully your first post to me with that Whaaa. From there came all other posts between you and me:

 

"

@rauliruegas

Null points calculation it not depends of any other parameter, not even tonearm EL.

Whaaaa???

you need to specify at least four parameters which typically are alignment type, inner groove diameter, outer groove And Pivot to spindle (P2S). The math then returns you two null points, effective length (EL) and offset angle. The overhang (OH) is then found by subtracting P2S from EL. The knowns and unknowns can be reworked based on the information available. Effective length can be substituted with a known overhang and the P2S returned.

dave "

 

""

Without overhang which requires an effective length to calculate the two null points cannot exist.

dave ""

 

""

I doubt Løfgren would suggest it possible to get two null points without the addition of overhang no matter how much you point him to his math.

dave """

 

What is all about?

 

Don’t you think that your last post should been the first one?:

 

"" those null points on a record surface and being able to trace through to them with a cartridge.....to get existence ""

 

Instead that you followed talking of calculations/math as me.

 

That’s is my stupidity.

 

R.

 

 

 

 

 

 

Dear @frogman  : You are rigth but the owners of that tonearm just posted that they like it and in reality no one gone in deep detail in their tonearms comparisons with selected LP tracks.

 

I even posted to intactaudio if he could share the LPs tracks that was using in his tests and his answer was:"dead silence ".

 

Such is life.

R.

I put my 9" HA arm up for sale a few easy-to-find places if anyone is interested. I’m still somewhat agnostic as to the discussion surrounding the fine details. Kind of tempting to try to put the arm to the test, but I’m mostly a 78 collector. Although I’m constantly exploring the frontiers of 78 sound engineering and restoration, I don’t have much interest in trying to break into the field of tonearm testing as a relative novice--I think I’ll stick with mysteries of the Soundsmith Strain Gauge for now along with the hot debate (in 78 circles anway) concerning digital IIR EQ curves and comparing them to their analog equivalents. That’s enough to keep me busy for months or years. For my second arm, I’m going to stick with something a bit more fixed--a few of the Viv’s adjustments were kind of troublesome with my particular plinth. I may regret selling it.

@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.

 

 

 

 

 

Dover, as you know, the single null point will lie on the radius of the LP and hopefully somewhere on the playing surface. I’ve been trying to visualize the setup you propose. Seems to me if you move the pivot forward of the null point but still short of the spindle ( pivot to spindle distance still greater than pivot to stylus) you just change the location of the single null. As soon as pivot to spindle = pivot to stylus, you’ll have no null point. And when pivot to stylus is greater than P2S, also no null point. I hope I’ve understood you correctly.