I removed the previous version. This one is correct.
Again same as above in the High setting, but now for the optimal VTA setting.
The weirdest thing to my opinion in the high setting is that the phase of the demodulated right signal has a phase shift of 90 degrees ?
Hans
Again same as above in the High setting, but now for the optimal VTA setting.
The weirdest thing to my opinion in the high setting is that the phase of the demodulated right signal has a phase shift of 90 degrees ?
Hans
Attachments
The image below shows the magnified spectrum around 3150Hz of the signal as recorded directly from the LP with a filter bandwidth of 2.7 Hz.
Left is again VTA High and right the optimal VTA.
Quite remarkable is that in the low position the main lobe and also the sidebands 1x(+/-315Hz) and 2x(+/-315Hz) are almost concentrated in one filter bin, whereas in the High position these lobes are smeared over more than one filter bin.
This is true as well for the left and for the right channel, so it is not an explanation why the FM demodulated signal from the right channel in the high position is behaving so weird.
If this smearing is the result of friction, it's fine to me, but I do not understand the mechanism behind.
Making the lobes as narrow as possible seems almost like a good method to adjust the VTA.
Hans
Left is again VTA High and right the optimal VTA.
Quite remarkable is that in the low position the main lobe and also the sidebands 1x(+/-315Hz) and 2x(+/-315Hz) are almost concentrated in one filter bin, whereas in the High position these lobes are smeared over more than one filter bin.
This is true as well for the left and for the right channel, so it is not an explanation why the FM demodulated signal from the right channel in the high position is behaving so weird.
If this smearing is the result of friction, it's fine to me, but I do not understand the mechanism behind.
Making the lobes as narrow as possible seems almost like a good method to adjust the VTA.
Hans
Attachments
I was thinking about things this evening and wondered if it is possible to create a track that allows stylus wear to be estimated? Ignoring the case of a chipped diamond, the most usual issues as I understand it with wear are a reduction in high frequency tracking as the contact point widens and (more importantly) the stylus sinks down the groove with wear until it starts riding the bottom of the groove.
Now the HF performance can be measured relatively easily and comparisons made over stylus life, although we may not be sure what we are looking for, but the groove positioning I fear is impossible as you can't change the shape of the groove. The only idea I had was a vertical modulation test that goes beyond the Specs and has very shallow peaks. In theory a lightly worn stylus would not stay in the groove whereas a worn one, riding lower might. As a test this is clearly a non-starter but thought it might prompt some ideas.
Now the HF performance can be measured relatively easily and comparisons made over stylus life, although we may not be sure what we are looking for, but the groove positioning I fear is impossible as you can't change the shape of the groove. The only idea I had was a vertical modulation test that goes beyond the Specs and has very shallow peaks. In theory a lightly worn stylus would not stay in the groove whereas a worn one, riding lower might. As a test this is clearly a non-starter but thought it might prompt some ideas.
OK, I'll bite. Audible differences? Measurable differences? Pataphysical differences?
Audible differences, you really think we were going to try and measure something with 7 - 8 audiophiles also there in the room with us?
We played a couple of my strain gauges, broke out the Windfeld and LL1941 SUTs to play with Scott's differential JFET phono stage (nice) and then the Muscovite with Windfeld and SPU A95 so people could get a sense of what they all sound like.
Anyone who thinks analog playback is accurate is deluded, pleasant yes, real sounding yes, but the differences we heard between the various cartridges and the pivoted arm (Schick 12 inch arm) vs linear tracker (Souther Tri-Quartz) should put that notion to rest. What is accuracy in this context, what is the frame of reference, it is certainly no existing arm or cartridge. Absolutely no measurements required, on my system the differences are not the least bit subtle. (Note all of the devices compared are the product of solid engineering design and not made by magic elves in some mysterious never never land.)
I have started using simultaneously released recent high res downloads and their vinyl counterparts to try and assess what combinations seem to provide the most similar presentation. (Punch Brothers Phosphorescent Blues sounds essentially similar on high res and vinyl as an example. There may be differences in the mixes, but differences if present seem quite minor in uncontrolled A/B comparisons I've done.)
It was quite interesting for me too, I understand even better why I like the strain gauges and have switched back. Two more people in the group are going to make the move to strain gauges as a result. They are however ridiculously sensitive to VTA.
We played a couple of my strain gauges, broke out the Windfeld and LL1941 SUTs to play with Scott's differential JFET phono stage (nice) and then the Muscovite with Windfeld and SPU A95 so people could get a sense of what they all sound like.
Anyone who thinks analog playback is accurate is deluded, pleasant yes, real sounding yes, but the differences we heard between the various cartridges and the pivoted arm (Schick 12 inch arm) vs linear tracker (Souther Tri-Quartz) should put that notion to rest. What is accuracy in this context, what is the frame of reference, it is certainly no existing arm or cartridge. Absolutely no measurements required, on my system the differences are not the least bit subtle. (Note all of the devices compared are the product of solid engineering design and not made by magic elves in some mysterious never never land.)
I have started using simultaneously released recent high res downloads and their vinyl counterparts to try and assess what combinations seem to provide the most similar presentation. (Punch Brothers Phosphorescent Blues sounds essentially similar on high res and vinyl as an example. There may be differences in the mixes, but differences if present seem quite minor in uncontrolled A/B comparisons I've done.)
It was quite interesting for me too, I understand even better why I like the strain gauges and have switched back. Two more people in the group are going to make the move to strain gauges as a result. They are however ridiculously sensitive to VTA.
Thanks for the report, Mr. K!
Having done just that, uh, yeah - don't recommend it.
One nice thing about this test LP is that we can publish the original files in 24/96 for comparison. Pink noise, or even a music recording could offer an audible check as to how close the playback system is.
That may be good for us and out test LP. I could allow us to understand what changes and how best to measure it.
Scott I think mentioned the same idea, it would definitely be helpful since I am already doing this informally when I have the matching recordings.
I will say I think the Schick/465C gets closer than any other combination I have on hand, the difference in performance between the various components evaluated today was quite sobering.
I hate to admit it but I mostly would rather listen than worry about these issues as long as nothing is obviously broken. Maybe I am jaded or lazy, but I am still digesting the results of the day, a rather stronger confirmation of what I had come to suspect over time about the varied personality of vinyl playback.
I will say I think the Schick/465C gets closer than any other combination I have on hand, the difference in performance between the various components evaluated today was quite sobering.
I hate to admit it but I mostly would rather listen than worry about these issues as long as nothing is obviously broken. Maybe I am jaded or lazy, but I am still digesting the results of the day, a rather stronger confirmation of what I had come to suspect over time about the varied personality of vinyl playback.
A couple of the wrong VTA settings I would consider borderline broken, the mistracking/sibilance verged on unbearable (or at least just plain wrong). I'm even more convinced that the STR112 400/4k track would show something dramatic with the Shibata stylus and VTA my stylus simply is not sensitive enough to get clear results.
That seems like a fair assumption.
The importance of VTA tuning seems to depend on the type of Stylus in use.
With my 3x60 um stylus having a long Contact Line with the groove, a VTA change of 1 degrees already showed rubbish for one channel in the FM demodulated signal, where a conical stylus could hardly make a difference.
Hans
The importance of VTA tuning seems to depend on the type of Stylus in use.
With my 3x60 um stylus having a long Contact Line with the groove, a VTA change of 1 degrees already showed rubbish for one channel in the FM demodulated signal, where a conical stylus could hardly make a difference.
Hans
No reason to think that's specific to strain gauge engines, of course: it's widely reported also for magnetic carts, especially for fine line styli. More likely generally follows stylus profile, IME.
The elephant in the room is that such alignment changes can't induce enough geometric harmonic distortion per se to be audible in programme material, and certainly not enough to bring about such profound audible changes. Example and sources already quoted on this thread. So another explanation is needed to explain what can be plainly audible and measurable to an extent way beyond the common-wisdom geometric explanation.
My thesis is that the cause is altered presentation angle of stylus-groove interface mechanics: specifically altered friction interface. And altered tracing/tracking is the consequential mechanism: stylus more closely follows locus of the groove base with lower friction.
Similar profound audible changes correlate with other ways of altering stylus-groove friction, IME.
Equally at issue are other axis angles, such as lateral offset angle, and azimuth. Pragmatically, a test record that can help align a stylus for minimal harmonic distortion of sidebands we are discussing here could provide a great way of finding the 'sweet spot' of alignment that can be so audibly important for fine line styli.
LD
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The patent briefly touches on the quadrature nature of mistracing versus geometric FM, arising because the point on the 300Hz wave at which the locus of the stylus deviates from 'ideal' is different. Also, geometric distortion should arise in both channels..........
Thesis is that smearing arises due to increase in random headshell motion consequential to increase in random stylus-groove friction stimulus. FM scrubbing. I don't know a better explanation, and it sure is otherwise odd......
Maybe there's some support for this in the lf spectrum of the demodulated signals ?
LD
That's probably the most important reason why I called it weird.
As you can see in posting #459 it occurs at this changed VTA setting only in one of the two channels.
The other channel is still behaving perfectly.
In posting #461 with the "correct" VTA setting both channels are O.K.
I don't know whether right or left is defined to be on the inner circle of the groove. But it could very well be that the more sensitive channel to VTA changes happens to be on that inner circle.
I already experimented with the lateral angle with no change, and the Azimuth also seems to be perfectly adjusted.
So the only remaining parameter left is the adjustment of the overhang which should be zero for a tangential arm.
And raising the arm from its horizontal position to change VTA, will also alter the overhang, not much but anyhow !
Hans
I completely agree, I have had a number of MC cartridges with line contract styli, currently own a Windfeld with a Replicant 100 LC stylus and if anything the Shibata seems even more sensitive to VTA/SRA. The differences a few degrees seems to make is not that subtle, so some not well understood mechanism seems to be at play if I understand you correctly.
I am at least sold on the idea that on the fly VTA adjustment is useful and will get a VTAF soon for the Schick.
I must re-read the strain gauge thread to see when the conversion came. Early on you thought they were good, but your Winfield was better! clearly you found some magic somewhere!
I need to double check as there are various errors around but the shibata appears to be 6x75um so similar major axis to most of the extreme profiles but larger minor radius. I don't have a minor radius figure for the replicant, but assume it's based on a Gyger/vdH profile so IIRO 5um and major is clearly 100.
On inspection you would think the major radius made the most difference to the twitchyness to VTA so will be interesting to find out more about that.
I wonder if amongst those posting here we have a fairly complete cross-section of current production extreme stylii to compare?
Aside: looking at the pics of your Schick I had to smile as I'm going to be going to the other extreme mass wise with a new puchase. I now have (but not faced the music with the boss) an SME3009 SIII with the ortofon wand. Total effective mass including cartridge is 4.5g. Should allow my stylus40 to perform at its best.
I need to double check as there are various errors around but the shibata appears to be 6x75um so similar major axis to most of the extreme profiles but larger minor radius. I don't have a minor radius figure for the replicant, but assume it's based on a Gyger/vdH profile so IIRO 5um and major is clearly 100.
On inspection you would think the major radius made the most difference to the twitchyness to VTA so will be interesting to find out more about that.
I wonder if amongst those posting here we have a fairly complete cross-section of current production extreme stylii to compare?
Aside: looking at the pics of your Schick I had to smile as I'm going to be going to the other extreme mass wise with a new puchase. I now have (but not faced the music with the boss) an SME3009 SIII with the ortofon wand. Total effective mass including cartridge is 4.5g. Should allow my stylus40 to perform at its best.
I may have realised the answer to my own question. I believe that the strain gauge carts track at somewhat higher VTF than the winfield, so even though the shibata is fatter any alignment inaccuracy will show up more due to the increased contact pressure (assuming the friction model is the correct one).
If this is correct then we should be able to test by wet playing and adjusting VTF? Small differences in VTA should then make little or no difference?
If this is correct then we should be able to test by wet playing and adjusting VTF? Small differences in VTA should then make little or no difference?