TW-Acustic Raven 10.5 or DaVinci Grandezza??


Seems like a crazy question!
I am getting a Raven one but will have a choice of the Raven 10.5 or DaVinci Grandezza for just $2000 more! Which should I go for? Well I am not sure if Raven one is a good match to this super arm but the 10.5 have got great reviews. Please give soem advice.
luna
Dear Dover, agreed - level of both platter and tonearm board is an issue in a good portion of turntables.
As we are dealing with pretty "small" (quantified in relative ..;-) ..) forces in tonearm alignment, full plane horizontal level is mandatory to ensure the absence of "parasite" forces which will alter the result and thus lead to misalignment.
Anti-skating rarely if ever is applied in any correct form.
Especially so, since skating force itself first is not linear over the groove AND depends on stylus shape, off-set angle and VTF.
Now add an armboard which isn't level ( I would estimate 90+% of all turntables out there ) and/or a turntable which' platter isn't level (talking about speed accuracy ...).

Key problem here is, that really a good bubble/spirit level is both - a bit more expensive but foremost: pretty heavy.
If you are looking for a precision aluminum level with say 0.6 mm/m accuracy for technical purpose, you are looking a something which itself already has a mass in excess of 1 lbs and is 8" long.
If you want to go further/do better - say 0.1 mm/m accuracy and a frame level which you can put nicely around the center of your platter and thus avoid leveling error by the instrument's mass - than we are talking US$500+ and a mass of 2.5-4.8 lbs with precision smoothed contact surface.
That will be accurate, but the sheer mass of the leveling instrument will falsify the result - at least on all turntables which are suspended with pretty low mass.
The spirit levels we see sold for audio purpose are only jokes.
A good way to go is the use of special architectural and measurement laser equipment which "draws" precise leveled lines on objects.
Thus armboards and platters can be leveled without additional mass.
OK, so a few of those incredible Italian industrial designers slipped across the border from Italy into Switzerland. Perhaps politics had something to do with that. One can see many Ferrari's zipping around Alpine roads. I was once overtaken by a 250GT on a downhill heading into Ventimiglia, at a speed never to be forgotten. First, a dot in my rear view mirror, then in an instant passing me, then in another instant a dot on the horizon. Alas, I was driving a rented Fiat.

If armboard is not plane parallel to platter, I would fix that not with azimuth adjust. Even if it made any sense to do it that way, azimuth adjust could only correct for one kind of error in the alignment, along one arc. Whereas, the error in armboard/platter alignment could describe any one of an infinite family of arcs.
Dear Lewm, of course you wouldn't fix a non-plane parallel to platter armboard with azimuth.
But there are enough audiophile who do - by error.
I was referring to this because I have found many situations with "azimuth corrected" cartridges which in reality was not a misplaced stylus but a ledge of the armboard towards the platter.
But as the level wasn't checked - precisely or at all - the "apparent" wrong azimuth was "corrected".
This was mentioned, to illustrate the point that "apparent wrong" azimuth isn't always what it seems on first sight.
DT, I thought it was someone else who actually suggested that azimuth adjustment is a desirable feature, BECAUSE of possible problems related to the spatial location of the armboard with respect to the platter. We don't disagree on this.

However, I do get a sense of security with tonearms that provide for azimuth adjustment vs those that do not. Unfortunately, the sad fact is that most tonearms that offer the feature also change VTA along with azimuth, because to change azimuth, they rotate the arm tube near the pivot, not taking into account the offset angle of the headshell. Best way to do it is right at the headshell, so only the headshell rotates and only in the vertical plane of the stylus tip. Only Reed does it that way, or some detachable headshells offer it as well.

Actually, I was wrong in my geometrical analysis; the situation is even worse than I wrote, if one were to try to correct for armboard/platter disorientation using azimuth. At the very best, you could only restore the proper relationship (platter plane parallel to armboard) at one single point across the entire surface of an LP. And that's assuming the error was within the arc described.
Well, at least SME and DaVinci honored what they think on azymuth and designed according that honest " attitude " and did not corrupted their " feelings " in favor of $$$ or against them " feelings ", good!

R.