SME V arm: dynamic VTF or straight weight

Dear all, does anyone like to answer and clarify the 2nd question raised by Peterayer's very interesting thread?

***Is there a sonic difference and what is the theory behind one versus the other?

I would think that using the latter method moves the counterweight closer to the arm's pivot point and effects how the bearing is loaded and possibly also the moment of enertia of the arm. ***

Because there is a very special dynamic behaviour involved here - one which goes far beyond counterweight vs. spring loaded VTF.

I just do not want to go ahead and being the "theoretical / math guy" again.

But there is a detail here, which has a very significant influence on the sound of the cartridge.........

I've talked with the SME people who say they cannot hear a difference. Maybe their hearing is not as acute as some on this forum........

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