ah I see what you mean. Not really that decadent compared with the price of some new cartridges these days.
Nice link George. I want one of those orsonic SG-1! That paper is a definite keeper, thank you.
ok I realised I needed to do more research on the variables with respect to tracking force vs compliance. Some graphs may be required. there is a correlation within 20% of the two variables, but not sure what else comes to play. Data to follow. But looking at the ortofon expression (11cu 2.6g replicant) you can track fancy profiles at high VTF.
Aside AJ van den hul has a weird mix. high compliance (35) in an 8g cartridge. By my reckoning about 5Hz.
Aside AJ van den hul has a weird mix. high compliance (35) in an 8g cartridge. By my reckoning about 5Hz.
I guess I'm the odd man out, voicing and equalizing win here. At least he picks the right FET.
Well I spent last night reading this, from the days before the vinylengine purges https://www.vinylengine.com/turntable_forum/viewtopic.php?t=24692 . I am none the wiser as to the VTF vs compliance part. It's sad, but I shouldn't be suprised that cartridge manufacturers aren't doing more to explain things. But there several 11cu cartridges out there with 2.6g VTF and line contact stylii with no horror stories about vinyl chomping so I think the concept is good.
Now off to think about how damping troughs reduce need for antiskate.
Now off to think about how damping troughs reduce need for antiskate.
Thank you George, it's good.
Naturally, like all the papers I've seen, it implicitly considers stylus-groove friction time invariant. This works as an average: however my thesis is that the time variant or noise element of stylus-groove friction is the interesting bit, and can also induce significant audible effects, not least crackle-pop surface noise, but I've never seen material written on that aspect.
I might be able to help clear up one enigma raised by the author as to why modulation drag increases for inner grooves.
The author uses an extreme example of 27.1cm/s velocity/equivalent level, so let's stick with that for now, but the same principles apply for any non-zero level.
Instantaneous stylus velocity is represented in the shape of a groove as the instantaneous angle made with with the natural line of the groove tangent. The angle the groove makes with its natural 'line'.
It's everso easy as a concept: instantaneous angle is set by the ratio of distance moved by a stylus laterally versus the distance moved along the groove per unit time. So the angle is set by the ratio of lateral velocity to linear velocity. Linear velocity is constant (except by spindle radius, see later), so groove angle = lateral velocity = programme level. Ta da.
So the author's extreme peak level of 27.1 cm/s would equate to a peak groove angle of about 32 deg on an outer track at a radius of 15cm. The same peak level would equate to a peak groove angle of about 50 deg on an inner track at a radius of about 8cm. In both cases, the same programme level is encoded, but the slower linear velocity of the groove for inner tracks means the peak angle of the groove shape is steeper for inner tracks.
Aside, peak groove angle occurs at a zero-crossing point of the groove shape, where curvature is zero, by definition. It is not the curvature of grooves that is at issue for most trackability limits, it is the instantaneous angle the groove makes with its natural line.
So consider the author's scenario of 27.1 cm/s on an outer track radius 15cm, when the stylus is instantaneously at the locus where groove angle is 32 degrees, its peak. For a sine wave this would be at a zero crossing point, in line with the natural groove line. The force to overcome stylus-groove friction remains constant (as confirmed by the author) but can only be applied via the cantilever along it's line.
So peak friction drag for this modulated outer track versus a silent groove increases by a factor of 1/(1-sin (32 deg)), ie a factor of about x 2.1 , whereas for an inner groove where the angle is 50 deg, the factor is about x4.3.
In this extreme example, there is a factor of about 2 between friction induced peak drag force on inner and outer tracks, and this IMO resolves the enigma raised by the author.
There is also a factor of about x4 between silent groove friction drag force and inner 27.1cm/s modulated grooves. If µ were typically about 0.4, this would mean friction drag applied for inner grooves at 27.1cm/s would be about x1.6 VTF, which when applied via a 45 degree wall would be untrackable. And indeed, it is untrackable on inner grooves but just about doable on outer grooves.
Some manipulation is needed to convert such factors to average values, because the sense of frictional drag is always positive: the rms level would be 0.64* peak for a sine wave.
In practice, the limit of trackability is typically a groove angle of between 30 and 40 degrees. Force required to move suspension compliance is additive to the discussion above, which only considers the effect of stylus-groove friction which IMO dominates.
I hope this ramble makes sense !
LD
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Just guessing. I suppose with high compliance (which may mean low mass cantilever plus more springiness) will resonate more. Right ? That's why some tonearm plus cartridge sound bright and some high mass arms lack high frequency clarity.
Regards.
Regards.
depends what you mean by springiness. high compliance means easy to move, so from one viewpoint less springy.
hmm not sure I can formulate an answer as lucidly as LD could on this as there is a complex interplay. At LF the spring/damping/mass of the system comes into play and you have to match arm effective mass with compliance to keep the fundamental resonance in the right ballpark*. Next up you get into tonearm resonances which are in the 300-1kHz area. With these the lower compliance carts in theory could put more energy in as there is more 'tail' to wag the dog with.
skip a few and you then get to the cantilever resonant modes. With these, lighter is better as it pushes them out of the audio band, although in some cases this resonance is used to prop up a falling top end.
All of which needs to caveat'd as there are an awful lot of 'it depends' and I'm still only scratching the surface.
As for me, still being tempted with an SME 3009 S3 or improved (fixed headshell) to see if I can get a combo with the LF resonance at 14Hz or above to test what B&K measured back in the 70s
skip a few and you then get to the cantilever resonant modes. With these, lighter is better as it pushes them out of the audio band, although in some cases this resonance is used to prop up a falling top end.
All of which needs to caveat'd as there are an awful lot of 'it depends' and I'm still only scratching the surface.
As for me, still being tempted with an SME 3009 S3 or improved (fixed headshell) to see if I can get a combo with the LF resonance at 14Hz or above to test what B&K measured back in the 70s
It does and thank you for taking the time to elaborate.
Lucky, what is the formula you use to come to this? (if you have explained it in the past, please link me to that post).
Acc to the equation Ff = Fv • µ this is not possible.
I looked closely at Fig.2 and Fig.3 for to find out what is the mu on those curves (see attachments).
The surprise (*) was on Fig. 3, where on 30cm/s modulated grooves, mu lowers when tracking force increases.
(*) well, it's counter intuitive but seems to agree with the anecdotes that higher tracking force seems to lower surface noise.
George
Attachments
A rare finding
http://www7a.biglobe.ne.jp/~yosh/images/Mechanical%20Impedance.jpg
Found as a link in this page from Yosh site
ƒeƒXƒgƒŒƒR�[ƒh
(translated through Google translate)
https://translate.google.com/translate?sl=ja&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww7a.biglobe.ne.jp%2F~yosh%2Ftestrecord.htm&edit-text=
Happy New year to all
George
http://www7a.biglobe.ne.jp/~yosh/images/Mechanical%20Impedance.jpg
Found as a link in this page from Yosh site
ƒeƒXƒgƒŒƒR�[ƒh
(translated through Google translate)
https://translate.google.com/translate?sl=ja&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww7a.biglobe.ne.jp%2F~yosh%2Ftestrecord.htm&edit-text=
Happy New year to all
George
It is only 🙂D😀) an extract from the technical 8 page sheet that accompanied Denon Vinyl technical test record XG-7001 (PCM Recording for Nippon Columbia, Made in Japan, 1976)
See also an extension of the above in the design considerations for the commercialised DL-103
DENON Museum - Model History -�@1970 - DL-103 - •ú‘——pƒJ�[ƒgƒŠƒbƒWDL-103‚Ì�«”\
https://translate.google.com/translate?hl=en&sl=ja&tl=en&u=http%3A%2F%2Fwww.denon.jp%2Fjp%2Fmuseum%2F
May the vinyl recording/playback technicalities warmly embrace you in the upcoming year 🙂
George
See also an extension of the above in the design considerations for the commercialised DL-103
DENON Museum - Model History -�@1970 - DL-103 - •ú‘——pƒJ�[ƒgƒŠƒbƒWDL-103‚Ì�«”\
https://translate.google.com/translate?hl=en&sl=ja&tl=en&u=http%3A%2F%2Fwww.denon.jp%2Fjp%2Fmuseum%2F
May the vinyl recording/playback technicalities warmly embrace you in the upcoming year 🙂
George
Attachments
Just been reading the linked page on tonearm building. The literal translation makes it tricky to follow, but some interesting stuff and a nice discussion at the end about various damping methods with patent references where he could find them.
Happy new year to you and all here too, George.
Like yourself, George, Yosh's compiled resources are most excellent and very well researched, plus he is a very generous and helpful guy, I have found.
This link is definitive about the significance of mechanical impedance and its relation to trackability, and the meaning of compliance@100Hz as specified by Japanese manufacturers: essentially a restatement of trackability performance at a given VTF, or what VTF is required to obtain a certain trackability if one prefers.
This is the definitive on the relationship between compliance and VTF.
When mechanical impedance is measured this way, all aspects that contribute to impedance are wrapped up together: suspension spring and damping, inertia, and friction. If trackability is measured across a frequency sweep, different aspects dominate performance.
I think it's worth noting the waveshapes during mistracking, especially at different frequencies, which show the different points on the physical grooves where the stylus loses contact. Especially that onset of mistracking is always on the inner groove wall first, for a sine wave, unless perfectly compensated by anti-skate force. This is because drag force is applied via the arm offset angle, effectively the groove angle is about 20 deg steeper when the inner wall presents its face and angles.
LD
You don't really more than 20cu. Compliance is only one parameter that determines VTF required. The definitive info on what's required is in various SHURE papers and summed up in
Holman, Dynamic Range Phono Preamplifiers, Audio July 1977.
I pontificate a little on that thread. If you remove the RIAA EQ from the pic in the thread, you sorta get the Denon curves but Holman has more complete info.
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As I've said earlier, the SHURE papers deal with both the cantilever modes as well as vinyl. Don Barlow certainly didn't just analyse static vinyl.luckythedog said:
I'm dredging up 30+ yr old memories but IIRC, elastic vinyl is necessary to explain how a low tip mass spherical stylus can have low distortion. The 'modern' example of this is Denon 103.
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My most successful foray into cartridge design was transplanting a (very low tip mass) ADC XLM stylus into a (less compliant) VLM body. The VLM compliance was more than sufficient for LF trackability even at 1gm but it also allowed increasing VTF to 2gm.
It moves one of the 2 HF resonances you normally see even further up. (The other remained the 'same' .. more evidence of wobbly vinyl 🙂 )
A bit of extra capacitance flattened the response to go with the better HF trackability 😀
You may need to have a low mass cantilever too. What is a S-120 ?
BTW, the resistance (not compliance) of the little rubber bung also provides most of the (effective) damping for the arm/cartridge. The V15-IV damper brush adds to this damping without requiring a more lossy (resistive) bung .. which would reduce MF trackability. I'm in two minds about this brush. It IS audible but provides so many benefits.
Damping at the arm pivot like the SME is the wrong place. see the Holman paper.
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The SHURE M24H cantilever adds a 3rd HF resonance to complicate things ... but if done right, helps HF trackability & response with sorta cheapo stuff.
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If tip mass is small, high VTF does NOT cause record wear ... Walton bla bla
2gm is a sensible value even with a Line Contact stylus. It's all SHURE's fault. Popularizing Trackability led to a race to have the smallest VTF to track various torture test tracks. This led to user expectations of 1gm VTF in day to day use.
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This thread is bringing back all sorts of Jurassic memories .. eg Acetates being quieter than vinyl 😀
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I'll end with 2 pts from Jurassic experience of ticks & pops
- Wet playing is really good
- 2gm is better than 1gm for ticks & pops.
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What I mean is that average stylus-groove friction force along the groove remains constant no matter what speed and direction the groove moves in. But tonearm drag it induces is subject to a mechanical disadvantage for a modulated (angled) groove, because the angled groove creates a lever.
Therefore if µ is 0.4 and mechanical (dis)advantage is 4, instantaneous drag force induced would be 4*0.4*Fv I think. When applied to an angled groove in this case, there apparently is an associated upforce which exceeds VTF: it's probably untrackable because the stylus would lift upwards momentarily, which is mistracking.
Same applies to drag induced by cartridge suspension movement. If the groove-stylus interface were frictionless, it doesn't matter to trackability what groove angle is presented, apart from mechanical impedance provided by the cartridge suspension and stylus inertia as the stylus follows the groove locus. If stylus-groove friction is present, the drag it induces depends on the angle the groove makes, ie programme material level, as well as the vinyl itself. This is why some vinyl tracks better than others, and it tends to correlate with surface noise and µ, IME.
I think it's very odd that µ is as low as 0.4 at 30cm/s when measured that way, for the reasons above but also because of cartridge suspension induced drag is bundled in when using that method. That is hardly altered from a silent groove, which can't be right I think.
I suppose that increasing VTF might affect µ inversely; what really goes on as to tribology at the stylus-groove boundary is unknown, at least by me ! Increasing VTF might help to reduce crackle-pop surface noise, perhaps for the reasons already mentioned: VTF sets the threshold which momentary variation in friction has to overcome in order to induce micro-mistracking and produce crackle/pop/tick noise, but don't write home yet because average friction, at least, scales with VTF in the first place. I suppose it's quite possible that tribology is such that noise variation and/or average value of µ can vary with VTF........
LD
Nice link, thanks will add that to my list to digest now that xmas is over and normality is returning.
I don't know anything about the ADC models but a quick google suggests XLM and VLM are same body, different stylus. As with most MM the compliance is in the stylus assembly. Am I missing something?
Ortofon S-120
There is a paper that argues both ends is the correct answer. I really must buy a copy sometime. I think Hans posted the link.
There are a lot of line contacts out there with compliance around 11 and 2.6g VTF. Is that not sensible?
No. You have it right. I should have said "XLM cantilever/stylus in a VLM bung" Both rubber bung & cantilever are in a replaceable stylus assembly.
The ADCs are interesting as the later ones (different magnetic circuit in the old body) had some of the best noise figures for MMs ... nearly as good as an Ortofon MC. (MCs may have low voltage output but they usually have high power output.. but you need a very LN matched preamp to see this. If you match it properly, the Ortofon MCs will have LESS noise than a MM.
Yes. That's sensible. I would want a bit more compliance .. maybe up to 20cu but matched to the tip mass for best HF trackability.
The old HiFi Choice books looked at many stylii and concluded Line Contact diamonds often weren't as well shaped as a good elliptical. A re-tip elliptical diamond from Expert Pickups would be as good as the most fancy LC.
Not sure if they are still in business.