Fun with vinyl measurements

[ElectricWarrior]

I don't 100% agree with that (apart from wedges having a greater control over vta correction in large numbers). The ~6mm up and down motion most tonearms in vintage turntables allow equates to roughly 1,5deg.
If you take a cartridge with a fairly normal static compliance of 30mm/N and a 6mm cantilever (which is standard), you have to raise or lower the VTF with 0,5gr tracking force to get the same correction (if my calculations are correct), which I think is quite a lot and can certainly impede tracking performance on a lot of cartridges.

Oh, interesting. I had tried it and thought it was more effective than that. Next time I'll make sure to document the changes in SRA/VTF.

Why would you want to have your tonearm absolutely level if not for VTA? I know it slightly changes effective length (therefore alignment with some protractors or gauges) and it could change vtf sligtly but you can easily compensate for that by doing the alingment with a different protractor and adjust the VTF to the correct amount.

Not sure, I guess it can make an audible difference? I keep reading that setting it higher will make things brighter, lower will make it muddier—if SRA was causing this, there would be a sweet spot that is the brightest, lower and higher would roll off the high end.

 

[Balle Clorin]

I don't 100% agree with that (apart from wedges having a greater control over vta correction in large numbers). The ~6mm up and down motion most tonearms in vintage turntables allow equates to roughly 1,5deg.
If you take a cartridge with a fairly normal static compliance of 30mm/N and a 6mm cantilever (which is standard), you have to raise or lower the VTF with 0,5gr tracking force to get the same correction (if my calculations are correct), which I think is quite a lot and can certainly impede tracking performance on a lot of cartridges.
Why would you want to have your tonearm absolutely level if not for VTA? I know it slightly changes effective length (therefore alignment with some protractors or gauges) and it could change vtf sligtly but you can easily compensate for that by doing the alingment with a different protractor and adjust the VTF to the correct amount.

That said, if a stylus needs so much adjustent that it apparently has a tracking angle of 28deg, I would call that stylus defective and shouldn't have passed quality control at the factory. That also raises the question of that track on that test record: is that track's purpose to fine tune/adjust VTA of which some say is very critical especially with line contact siontyle stylii (wheter or not that is true remains to be seen) or is the purpose of that track to filter out defective stylii that are just way off?
That's why I'm so keen to know if anything can be seen (with a microscope or macro lens) when that stylus sits on the record, so how apparant it is that it's off.

Jico wrote to me an confirmed that the Jico SAS and non SAS has different angles for the Shure V15-iv, and that at the increased imd distortion could be elimited by using a higher tracking force. The close to 30 degree seems to be normal for the SAS B- a strange choice i think...especially when they use a 20 degree end cut cantilever
updated post..with pictures

Fun with vinyl measurements

Or the mysteriious crosstalk issue … https://www.audiosciencereview.com/forum/index.php?attachments/ortofon-catrs1007-sweep-l-png.491537/

www.audiosciencereview.com

 

[Thomas_A]

There are many cartridges with wrong VTA. I shimmed my Shure/JICO SAS 7 degrees.

Fun with vinyl measurements

the purpose remains the music if it is not heard what is the point? ;-) (on very demanding music and trained and demanding listeners for example... for many factual reasons, the piano often comes back ;-))

www.audiosciencereview.com

 

[Thomas_A]

Test of VTA by DIN 45 542 record, low IMd% show match with VTA, Shure V15-iv JICO SAS-B for and AT OC9MLii
View attachment 494009


Jico SAS-B for Shure V15-iv, I get 29 degrees VTA at 1.25gram VTF so that fits with the above
View attachment 494197View attachment 494206
Since the tip tilt is about 20degrees on my Jico it ie probably Obray, looks like one too A 20 degree VTA would then give SR of 90, but since my Jico has a VTA of 29 degrees,,,,the SRA is more like 99 degree, a wedge should be used I think

The problem is also the tip exension. I never measured 99 degree SRA, more like 94. Shimming 7 degree gave 86-87 degree SRA

 

[Balle Clorin]

But is not that too low? , goal is 90-95=92? I have returned styli with SRA of 85

 

[Thomas_A]

SRA can

But is not that too low? , goal is 90-95=92? I have returned styli with SRA of 85

I did not get any odd measurements though. My current V15V JICO SAS is shimmed around 5°, so SRA about 90°, and about 25° cantilever angle.

An interesting issue is what VTA or SRA does to azimuth (if anything) and what the VMA is for the Ortofon test record andof the CA-TRS1007.

 

[Balle Clorin]

Maybe the lateral and vertical sweep on CA TRS-1007 can be used for zenith and VTA evaluation?

 

[Thomas_A]

Maybe the lateral and vertical sweep on CA TRS-1007 can be used for zenith and VTA evaluation?

It would be good to know the vertical modulation angle of the CA-TRS1007. If it is a true copy of the JVC it should be the same, but I do not know the VMA from any of them.

@Balle Clorin can you look at distortion of the mono and out-of-phase sweep of the Shure and the AT?

 

[sqrl]

Oh, interesting. I had tried it and thought it was more effective than that. Next time I'll make sure to document the changes in SRA/VTF.


Not sure, I guess it can make an audible difference? I keep reading that setting it higher will make things brighter, lower will make it muddier—if SRA was causing this, there would be a sweet spot that is the brightest, lower and higher would roll off the high end.

I had a cartridge with rolled-off treble and found that each millimetre increase in the VTA adjustment led to a 0.05dB increase in amplitude at 20 kHz.

 

[Balle Clorin]

It would be good to know the vertical modulation angle of the CA-TRS1007. If it is a true copy of the JVC it should be the same, but I do not know the VMA from any of them.

@Balle Clorin can you look at distortion of the mono and out-of-phase sweep of the Shure and the AT?

AT OC9MLii 48K RECORDING, Lateral then vertical, som low end filter must hav been active here

 

[Thomas_A]

AT OC9MLii 48K RECORDING, Lateral then vertical, som low end filter must hav been active here
View attachment 494464

RIAA pole?

 

[Thomas_A]

I reread Yosh paper about VTA. Clearly VMA angle at cutting affects crosstalk if not matched with cartridge, and explains why crosstalk will vary between cartridges, ie not be minimum at +/-45 degree but perhaps +/- 42 or +/- 46 degrees with the Merolemez test record (also with unkown VMA cutting angle). The reason why Ortofon and Clearaudio records gives different crosstalk values for the same cartridge is most probably due to different VMA at cutting. What the values are is unknown but my guess is that the Clearaudio is cut with a lower VMA. This is base on my findings when lowering VTA with shims getting lower crosstalk with the Clearaudio and higher with the Ortofon. Not only stylus VTA affects but also generator VTA which complicates things. Perhaps also the SRA angle affects.

My guess is that Ortofon is cut with 24-25 degree VMA and Cleraudio with 18-22 degree.

From Yosh paper and if I get it correct. VTA/VMA angle difference and crosstalk:

 

[Thomas_A]

AT OC9MLii 48K RECORDING, Lateral then vertical, som low end filter must hav been active here
View attachment 494464

Don’t really get the graphs. Why is distortion level like that? Can you split L and R (empty track in the other channel) and run it in the SJplot?

 

[Balle Clorin]

For som reason the SJ plot fails in the file, max 48 k samples, that cause the drop in distortion

 

[Thomas_A]

For som reason the SJ plot fails in the file, max 48 k samples, that cause the drop in distortion

Hm, don’t get it. The L and R sweeps work at 96k but not the L+R or L-R? Or did you just make 48k for these files?

 

[Balle Clorin]

Strange this works ,

But not this

USING MY TIME SERIES SCRIPT i GET THIS

Spoiler: WITHOUT SILENCE

Manual extraction of file works.

 

[Thomas_A]

Strange this works ,
View attachment 494478

But not this
View attachment 494479

USING MY TIME SERIES SCRIPT i GET THIS
View attachment 494480

Spoiler: WITHOUT SILENCE

View attachment 494481

View attachment 494482

Did you clean up the L+R and L-R? I split R and L and the silence one channel bfore scripting. You loose crosstalk but not relevant anyway.

 

[Thomas_A]

Strange this works ,
View attachment 494478

But not this
View attachment 494479

USING MY TIME SERIES SCRIPT i GET THIS
View attachment 494480

Spoiler: WITHOUT SILENCE

View attachment 494481

View attachment 494482

Manual extraction of file works.
View attachment 494484

Is it L+R or L-R?

 

[Balle Clorin]

See track listing
(1=L 2=R)
(3=L+R 4=L-R)

 

[Thomas_A]

See track listing
(1=L 2=R)
(3=L+R 4=L-R)

So blue is L, dashed blue R, for R+L. And red is L, dashed red is R, for R-L? Problem is that distortion will not be seen for both.

I take the R+L and split channels, empty the R channel, make stereo again and save as L. For right i flip channels, split, empty the R channel, make stereo again and save as R. Run the script and you get L+R with distortion both channels. Same procedure fro L-R.