I have written a few posts about this topic in various places and would like to move those posts here for reference. I will delete them from other threads which took some of those discussions off topic. I am always willing to learn more from those with different ideas or more experience than I have. I welcome any comments and information relating to this topic, and please do not hesitate to correct my ideas if they are wrong.
My thoughts on cartridge/arm set up
- Thread starter PeterA
- Start date
Peter,
What is the height corresponding to the exact horizontality of your 12 " tonearm? Are you setting the VTF using the spring system of the SME?
What is the height corresponding to the exact horizontality of your 12 " tonearm? Are you setting the VTF using the spring system of the SME?
Peter
did you do this over the platter of the SME?
are you aware that a 2 mm record will decrease the magnetic attraction between the cartridge and the platter, compared with a 1 mm record ?
did you do this over the platter of the SME?
are you aware that a 2 mm record will decrease the magnetic attraction between the cartridge and the platter, compared with a 1 mm record ?
microstrip, Are you asking how high the arm is above the platter when it is horizontal? Or something else?
I use the dynamic tracking force, or spring dial. I have tried the static balance, but I prefer using dynamic balance.
awsmone, did I do what over the platter of the SME? No, I was not aware that there was a magnet attraction between the cartridge and the platter. How much do you think it affects the VTF measurement? I could weight the cartridge over the platter and again over a wooden table to see if there is a difference. I think my scale's platform is about 3mm above the surface on which the scale is placed. When measuring VTF, I actually raise the arm higher than usual to compensate for the fact that the scale is 1.5mm higher than the thickness of my average LP.
With the SME 3012R, I set the VTA for the cart in question with a 180 gram record. Still sounds great with 150 and 200 gram records with no re- adjustment of VTA. Since there is no VTA option on the fly for this arm, that is what I do. It simply is not worth the time and effort to adjust for every record. If I am playing a record with a Graham arm, I will make the adjustment since it’s on the fly, quick and easy to do and there is a reference spirit level to keep VTA consistent from record to record. For some reason, the Graham is more sensitive to VTA changes on different thickness records and the SME is not.
I'm not surprised, Christian. My SME is not easy to adjust, though it is easier than the 3012R. Arms like the Graham, the Triplanar, the early Durands etc are designed for frequent, repeatable VTA adjustments, and I think some users take advantage of that. I have heard that the 3012R is not as sensitive to adjustments, and that they are less necessary. That is good as it saves you the hassle. Some cartridges seem also to be more or less sensitive to SRA changes. The important thing is to know your gear, use it the way in which it makes the most sense for you, and to simply enjoy the music.
Two facts should be pointed out in discussions like this one.
1. Dynamic balance is a misnomer when applied to tonearms. This is a term used to describe the balancing of a rotating system while under rotational motion, such as balancing a tire/wheel combination. Using a spring to apply VTF metely employs the stored energy in the spring to that end. The alternate way of applying VTF is to use gravity by unbalancing the tonearm with its counterweight. It’s unfortunate that the term dynamic balance has worked its way into the audiophile lexicon over the years.
2. The variation of VTF with respect to height of the stylus is solely dependent on the condition of static balance designed into the arm. Three conditions are possible, and are described as stable, unstable and neutral. In stable balance, a condition of most every arm, the center of gravity of the arm lies slightly below the vertical pivot, i.e., an imaginary line drawn between the centers of mass of the forward (cartridge) and aft (counterweight) portions of the arm passes below the vertical pivot. In an unstable arm, the CG lies above the vertical pivot. In a neutrally balanced arm the CG is exactly coincident with the position of the vertical pivot. Only in this last case is the VTF in such an arm independent of the vertical position of the stylus. I am aware of only two arms having neutral balance - the one designed into the original AR turntable and all variations of Bob Graham’s Phantom tonearms. As I said most tonearms are designed with weak stable balance, that is, close to neutral. If you disturb such an arm vertically when it is balanced with zero VTF it will tend to return to its preferred position. This means that in playing mode, any position of the stylus above the measured VTF point will cause VTF to increase, and any position below the reference point will result in decreased VTF. If you disturb an unstable arm in the same way, it will want to rotate all the way around to find its stable position, so that VTF will decrease for any vertical position of the stylus above the reference point, and increase below the reference point. The only unstable arm I am aware of is the Triplanar, though it is still very close to neutral. Bottom line is that most arms are designed with fairly weak stable balance so that variation in VTF due to thickness of discs and warp conditions are pretty small and would be difficult to discern audibly. One thing to look for when shopping for a tonearm is to notice the vertical position of the counterweight with respect to the vertical pivot, which would be an indication of its state of stable balance, or lack thereof.
1. Dynamic balance is a misnomer when applied to tonearms. This is a term used to describe the balancing of a rotating system while under rotational motion, such as balancing a tire/wheel combination. Using a spring to apply VTF metely employs the stored energy in the spring to that end. The alternate way of applying VTF is to use gravity by unbalancing the tonearm with its counterweight. It’s unfortunate that the term dynamic balance has worked its way into the audiophile lexicon over the years.
2. The variation of VTF with respect to height of the stylus is solely dependent on the condition of static balance designed into the arm. Three conditions are possible, and are described as stable, unstable and neutral. In stable balance, a condition of most every arm, the center of gravity of the arm lies slightly below the vertical pivot, i.e., an imaginary line drawn between the centers of mass of the forward (cartridge) and aft (counterweight) portions of the arm passes below the vertical pivot. In an unstable arm, the CG lies above the vertical pivot. In a neutrally balanced arm the CG is exactly coincident with the position of the vertical pivot. Only in this last case is the VTF in such an arm independent of the vertical position of the stylus. I am aware of only two arms having neutral balance - the one designed into the original AR turntable and all variations of Bob Graham’s Phantom tonearms. As I said most tonearms are designed with weak stable balance, that is, close to neutral. If you disturb such an arm vertically when it is balanced with zero VTF it will tend to return to its preferred position. This means that in playing mode, any position of the stylus above the measured VTF point will cause VTF to increase, and any position below the reference point will result in decreased VTF. If you disturb an unstable arm in the same way, it will want to rotate all the way around to find its stable position, so that VTF will decrease for any vertical position of the stylus above the reference point, and increase below the reference point. The only unstable arm I am aware of is the Triplanar, though it is still very close to neutral. Bottom line is that most arms are designed with fairly weak stable balance so that variation in VTF due to thickness of discs and warp conditions are pretty small and would be difficult to discern audibly. One thing to look for when shopping for a tonearm is to notice the vertical position of the counterweight with respect to the vertical pivot, which would be an indication of its state of stable balance, or lack thereof.
Thats actually untrue about the 3012-R, changes of even a couple microns to the VTA has huge sonic impact with most cartridges but I never felt the need need to continually adjust VTA/SRA when it was setup properly from the start.
david
Thank you for the correction, ddk. Do you feel that the huge sonic impact of very small variations of VTA, the kind you get when playing different thickness LPs for example, do not distract you enough from the music to make adjustments to the arm height necessary? Is it something you hear but don't want to be bother with the hassle of making the adjustments with the 3012R? As you know, I am considering adding the 3012R on an outboard arm pod to my turntable, but the lack of easy VTA adjustment is giving me second thoughts now that you say these differences have a huge sonic impact. I had incorrectly assumed that the "natural" tone of the 3012R overrides or glosses over what I thought were slight variations in sound from imprecise SRA.
For me, the adjustments I make on the SME V-12 improve the sonics and let me hear more accurately what is on the recording. I agree, slight variations in VTA are clearly audible, to me much more so than the slight changes in VTF and overhang that may or may not result from the changes in arm height. I often wonder if the usual lack of adjustment accounts for inconsistent enjoyment of a batch of LPs heard in some systems such as those at dealerships or shows where the arm has been optimized for one standard set up LP or is set up as a compromise for, or what sounds best on, a variety of different LPs.
Keith, I'm not sure that people are actually worried about VTA, but I think if someone wants to listen to vinyl, not considering VTA during the initial set-up process would be a mistake. It is one of the key variables affecting proper cartridge/arm alignment. Even if done only once and forgotten, one must pay attention to it during the initial set-up in order to get good results.
Then again, one could always just listen to digital instead and not worry about any of this stuff.
Thank you for correcting my notion of dynamic balance, miniguy. Great information in you post. Have you compared the sonic effects of an arm like the SME while in spring loaded mode and static balance mode? If so, could you describe what you hear and what advantages the manufacture might ascribe to a spring loaded system? I always thought the spring load presents a more stable VTF during sudden changes in VTA like those encountered during the playing of a warp. On a perfectly flat LP surface, I would think there is no sonic or practical difference between the two methods of applying VTF, but I don't really know. Another consideration may be to see which method allows for the counterweight to be more closely located to the arm's pivot point for a reduction in the arm's inertia.
No typo wrong unit of measurement, my bad. What I meant was 0.2-0.3 mm, thank you for catching it!
david
I don’t hear anything off after setting the VTA for use with standard records, going to 200g vinyl would need minor adjustment but I never bought any to care.
david
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In my experience the difference between spring-applied VTF and gravity on not completely flat records is essentially theoretical. The increase in VTF in an arm with stable balance while traversing a warp zenith, for example, would be exactly the same regardless of how VTF is applied. Warp tracking performance, however, could be dependent on the distance of the counterweight from the vertical pivot. But the effect on arm inertia would generally be confined to a small change within, say, a 1 or 2 Hz range, and the change would not be very audible. The advantage of a tonearm designed with inherent neutral balance, like the Phantoms, is that one can spend less time worrying about all these considerations as a source of audiophile nervosa and spend more time enjoying the music. Even with well designed stable balanced tonearms, changes in VTF due to warps and record thickness are just too small to worry about, and IMO there is no need to adjust arm height to compensate for record thickness. One is better off setting SRA for average record thickness and be done with it.
With the SME 3012R, I keep track of the number of playing cards (stack) I use to set VTA on various carts. They are initially set up for mid weight LP’s...180g. If I want to maximize VTA for a 200g LP..I add a card or two to the stack and cram them in the back of tonearm while loosening the VTA hex tower lock to raise it or lower it simply by subtracting cards. It’s a simple and rather ingenious method I learned from David.
