SME V arm: dynamic VTF or straight weight

Hi DerTonarm,
if you read my post you will find that I have addressed the point from a sound response point of view.

I have tried counter weight as close as can be, in the middle and pretty much at the extreme end of the weight adjustment.

There is NO difference in sound between the middle and very close up. Someone with 'bats-ears' MIGHT just make a case for not using the very outer end of the adjustment (I'm sure I have said as much i.e. what looks good works good...

Here again we run into an issue of maths vs hearing.
Let me hasten to mention, that I have just done another upgrade step on my crossover and I can hear VERY DEFINITAVELY a change from a 5R6 5watt Kiwame (carbon film) resistor to a Mills MRA5 5R6 (5watt) in the tweeter resonance compensation, which is NOT in the signal path as such. So, I guess my hearing is jolly good to be able to hear this (it was the right thing to change the R BTW :-)

So, I say NO discernable difference between dynamic and non-dynamic, and also no discernable difference between middle or close to the pivot post counterweight. The maths would surely come up with something other than my hearing, so be it.
Greetings,
Axel

Hi Axel, the difference between the dynamic balanced status and the static balanced (.... I will not bore you or anyone else with the maths here - promised!) status will not be heard on "first sight". However - if you play a record which is warped, you will notice the difference much sooner.

The sound is more relaxed and more stable (reason why so many people address the dynamic balanced status as being less dynamical, less lively). Opera-recordings with large soundstage and a lot of action on stage will give another good example. The "picture" is more stable there too. The focus of the individual voices is better and the timbre always stable.

In the static balanced tonearm the moving mass of the tonearm puts a very dynamic force on the cantilever/suspension system as soon as the stylus begins a hill-and-valley rally on a warped LP.

In other words: - in a static balanced tonearm the VTF is always changing if there are ANY vertical differences in the surface of the LP (and there are in EVERY LP - to a larger or lesser degree).
It may sound more dynamic to some - but is in fact just "unstable conditions".

This applies to a dynamic balanced tonearm to a MUCH lesser degree. Thats why a given cartridge/tonearm combination does always sound comparatively "quiet" and more "relaxed" in dynamically balanced status.

Thats the reason why most of the top-of-the-line tonearms from the "big" companies of the 1980ies did feature dynamically balanced designs.

From the pure technical point of view the working conditions for the cantilever/suspension (...VTF) are much better (read: more constant VTF) if mounted in a dynamically balanced pivot tonearm.

This must NOT mean however, that all audiophiles will find the sound in their specific set-up better with dynamic balanced status. Some may prefer static balanced.

Hi DerTonarm,
(I feel a bit silly to keep calling you that name --- is your first name a secret, if so, so may be it. I'm surely not talking to Juergen Eggers :-)

Back to the subject on hand. I do agree, whow! with EVERYTHING you state above (must be the maths that out of the way of hearing.

In a lesser, more affordable design e.g. RB300 there are possibly other factors at work also, that make a case for using it static as a preference --- never has one so i can't tell for certain. My friend has a Thorenz 'RB250' and a J. Raeke 'RB300' both ARE dynamic designs, and in his rig a Z-3 I can not make out any difference. That said, it is actually quicker (in general) to set-up a dynamic arm, if the scale can be trusted. I do trust SME, correct me if that is wrong.

One know exception to easy set-up is the new 12" Ortofon. I think a dynamic 12" tends to be more tricky in this respect in any event though. Furthermore, not my own experience and you might be able to comment on this some more, is the preference for 12" arms to run just static ---- it's got something to do with the maths? Not that I can see it, so it might just be the set-up issue and a subsequent variability due to the much longer lever compared to a 9".

Furthermore, I found that having used a Technics analogue VTF force gauge, that it was not as accurate as I would have liked it, and in particular when having to set-up 2.6g as is required according to spec. for a PW.

Best,
Axel

Dear Peter: Maybe the today SME dinamicaly balanced design already fix ( through damping ) that string vibration/self-resonance and this can be one of the reasons why some SME owners can't hear any differences even than the counterweight in the static way is close to the pivot and that in very tiny way that improves a better moving mass control and very tiny too change in the tonearm effective mass.

About the theory of dynamic against static way ( letting out the string resonance subject ) there are some interesting things: if the record is totally flat the cartridge performance is almost the same and certainly extremely difficult to say which is one, but the perfect world does not exist so in real conditions both tonearm designs suffer of almost the same " problem ": changes in VTF due to the gravity force, that's why between other things is so important/critical the bearing quality design in any tonearm.

It is almost imposible to make a bis a bis ( same tonearm/cartridge combination and same everything but the dynamic/static subject design. ) shoot-out in our own systems to find out what we like it ( that at the end is a subjective an unique opinion ) and even if we can/could do it there will be several different opinions.

This whole dynamic/static tonearm design subject is something like the one " geometry tracking distortions that we all analize through other hreads " that when some ask about the threshold where the tracking distortions could be hear/heard and we can't had an absolute and precise answer.
If we make the distortion measures ( in a scientific way ) and kind of it and where happen and translate those measures to what we hear this could be great but IMHO even if we can do it it will be extremely dificult to co-relate those single distortions with what we heard because it is almost impossible to have over control all the factors that are involve in the record playing exercise.

I think that in the tonearm case a critical factor is the quality execution ( between others. ) of the tonearm design it is here in the quality excecution where there are more important differences between different tonearms than in the dynamic/static subject. IMHO both approaches/designs could and can work with exeptional precision and great results even with its each differences/trade-offs.

Regards and enjoy the music.
Raul.

Dear Axel, 12" to 9" in dynamic balanced status - well, there a a few points to be taken into account. First of all the 12" tonearm is - due to his higher mass and to the longer lever - more stable (= his tendency to leave balanced mode is slower.....). One the other hand the counterweight has either to be heavier or has to be moved further away from the bearing. I have compared my FR-64s, MAX-282, MAX-237 and FR-66s for their behaviour in static vs. dynamic balanced mode. All were used with 3 different FR-cartridges (FR-702, FR-7f and FR-7fz). All were aligned with the Denessen tractor which does result in more effective length on all 4 tonearms and the 2 zeros fairly wide spread and the 2nd zero close to run-out-grooves.

I personally do prefer the dynamic balanced mode due to a more relaxed sound and a more stable soundstage. The sound has a kind of "inner ease" compared to the static balanced mode. The static balanced mode gives however - on brief listening - a sense of more excitement, more dynamic sound. This is uncovered after a few record sides rather as "exaltation" and "over nervous". In a system with rather low efficiency speakers this may however be desired and will add some "life" to the sound of the system.

If your music-system is already rather on the "fast side of life" (= high efficiency speakers etc.) the dynamically balanced mode will show its sonic virtues.

To my ears the sound of the dynamic balanced mode does support the theoretical background.

Have a nice evening,

Daniel H. Kurt