SME V arm: dynamic VTF or straight weight

Dear Axel, damping is always used to minimize the (always negative...) effects of unwanted vibrations sourced by resonance or torsion. Cartridge sourced vibrations are the result of too low compliance for the given effective mass of the tonearm. A hard (= low compliance ) cartridge can cause the tonearm and its bearings to vibrate to a degree which will have very pronounced effects on the sound. Damping is always used to reduce these unwanted vibrations (better: - to minimize their sound degrading effects).
But - these vibrations are the of a missmatch to begin with. Its not only a matter of the resonance frequency - its a matter of energy handling abilities and too small tires on a car with lots of torque and power......... now you ask the motor-management to reduce from 300 PS to 135 so that you can keep the car on the road.

The heavier carts do add another problem, as they do enlarge the effective moving mass quite considerably (as they are located at the farest point of the stylus-bearing distance) - a big problem with many of todays top-priced cartridges (good example: Koetsu's w/ stone bodies) which do feature too high "body mass" with comparatively high compliance. Thats why so many of the old Koetsu Black are cherished and still fetch new sale prices - they have by far the lowest compliance of all Koetsus and a "normal" weight. They do perform very well in almost all tonearms.

Damping may and will better the sound if your tonearm is matched with a cartridge which is not really ideal suited to be mounted in that particular tonearm.
But still - this particular cartridge would perform better in other tonearms, more suited to match its technical parameters.

In other words - damping is never needed and the sound will never benefit from its use IF cartridge and tonearm do mate well with each other.

We sometimes need damping, if you want to use a specific cartridge in a specific tonearm........ but it is never a happy wedding and not an ideal marriage.

Cheers,
Daniel

Hi DerTonarm,

cart compliance is a major input parameter in the calculation of arm / cart resonance, yes?

So, I'm trying to figure were we are regards the maths part of it.
Unless you are saying, a medium mass arm with a higher weight cart becomes a (sort of) higher mass arm. If that is so, then we are actually making things better, considering a medium compliance (12 ~ 16CU), or?

If, as you suggest the cart is heavy (stone body etc.) and the compliance is high (24 ~ 36CU) than the maths should again show, that resonance is out of the acceptable band as mentioned earlier (7.5Hz ~ 12Hz). Or do we have here the first case were the maths/facts do not tell the full story?

Interesting is, to my current understanding and assuming a 'reasonable' cart weight (5.5 ~ 8.5g), a high compliance cart with a light-mass arm, such as was the rave was in the 80s for a while, actually creates lesser IGD issues, YMMV.

There are of course other factors why compliance 'generally' has moved back from that dizzy height (very soft) of e.g. 36CU, to something in between to the other extreme, the VERY stiff (low compliance SPU, DECCA, EMT, etc.) of the 60s.

Now, will the maths tell it, or not?
If not, we all would be relinquished to try lots of different arms, or as I also said, not be able to listen to some marvellous carts.
Makes you think, doesn't it?

Greetings,
Axel

Well said, Daniel. As some have said on this forum, the arm and the cartridge and their 'marriage' are often more important than the platform they sit on.

Hi Axel, well - usually I did not get very sympathic comments here whenever I refered to math/geometry in analog playback set-up.

Maths would tell the story here too, but I will put it in more general words:

- the heavy cartridge body does add to the effective mass of the moving system (tonearm + cartridge + generator - NOT stylus) in a very special way. The body mass of a heavy cartridge can - and will - alter the effective moving mass extremely. Thats why the "regular" calculations (middle-mass tonearm + medium to high compliance cartridge ) are all a sudden null and void. One of the reasons why so many audiophiles aren't thrilled with the sonic performance of the high-priced (and heavy....) stone-bodied Koetsu's.
These cartridges are almost impossible to mate well with ANY tonearm.

High compliance - low compliance - medium compliance - these are are results of special requirements in the design of a given cartridge. This has to do with interaction between magnetic force, suspension material, cantilever stiffness, moving mass of cantilever/stylus and several other factors.

Jonathan Carr could write you a 2 pages post about these.

Coming back to this topic here, - and to concentrate the output.... - the cartridge bodies weight has such a big influence (if of considerable mass) on the behaviour of the tonearm and on its effective moving mass, that it can make it impossible to mate a particular cartridge with ANY tonearm.

A stone-bodied Koetsu will perform well in a very few tonearms. In these tonearm it does so, because these arms do feature outstanding energy transfer abilities and are extreme stiff and rigid. But even in these tonearms it is still a missmatch because the combination of high compliance PLUS high body mass is a NO GO for any tonearm. (God, - the Koetsu-lovers will kill me..... hey there! I like Koetsu's too, but would always go for the RSP....).

IGD - has nothing to do with compliance or mass alone.

Usually you are better off, if your cartridge is a good "tracker".
IGD can most likely be avoided, if your alignment goes for the 2 zero widely spread and the 2nd close to the run-out grooves.
IGD is a question of geometry and trackability. Many high compliance MMs do feature extreme trackability - but this alone does not mean low IGD.
Align a Shure V15VMR with IEC-geometry and play a DECCA SXL with Ravel Daphnis & Chloe conducted by Monteux:

You will get IGD even with the 100µm+ trackability of the Shure.
Because your Shure's stylus will already be close to its maximum error with the big crecsendi on the sides end.

An ultra hard 5-6 compliance FR-7 will easily go through those inner grooves without any distortion if mounted in a FR-60-series and aligned with a Denessen tractor.

Greetings,
Daniel

Hi Daniel,
let me get used to this now --- and welcome once again "In der Loewengrube"

>>> A stone-bodied Koetsu <<<
Yes, I hope you'll survive that one. I get your point, and if only for one reason: the other end of that spectrum the DL-103 i.e. a light body with a very low compliance.
This will need some heavy mass arm, end of story.
But now go to the resonance calculation it will confirm this (I bloody well hope so!)
Daniel do us a favour, go check: http://www.resfreq.com/resonancecalculator.html
and let us know if you're findings will be different. And if so - why?

>>> Usually you are better off, if your cartridge is a good "tracker". <<<
Well, right on the money I say --- BUT trackability was the very reason why folks like vdH went to the extreme of 36CU, right? And the Shure V15's (I owned one ages ago) also. Yet again a BUT, the problem I recall was, the EXTREMLY low VTF used in order not to bottom it out in the first place!

Now lets look at some of the low compliance carts. There is not a single ONE, that can claim better than 60µm, yes? Which is a pretty poor showing --- just looking at the maths :-)
Now one more BUT, they also use humongous VTF! 4g and more! If that needle (almost all had a round type, conical stylus then) dropped on the vinyl it made some sizeable pit mark. So it didn't track too badly because it used VTF like a ton of bricks.

So let’s have your take on that resonance-calculator's findings please. And we'll watch out for those lions not get us chewed up over Koetsu and Denon...

Greetings,
Axel