Fun with vinyl measurements

[Thomas_A]

Or the mysteriious crosstalk issue …

https://www.audiosciencereview.com/forum/index.php?attachments/ortofon-catrs1007-sweep-l-png.491537/

 

[melloncolliecat]

Sony PS-X555es and PS-x800 also take normal cartridges. But are also expensive and notoriously unreliable, especially the ps-x800 which is probably the world's most complicated turntable to service (I think there are about 30 trimpots inside, compared to for example 4 trimpots in a technics sl-10....)
Great turntable when it works though...
Lots of linear trackers also don't have VTA (I think the PL-L1000 does have that feature!) so that is something to look out for too if you want to extent your experiments.
But the PL-L1000 also has it's problems and is a bit 'plasticy' in it's construction (the lower half but maybe that can be damped). There's no perfect turntable alas....

A budget choice for linear arms with SME headshells is the Saba PSP-480, a bunch of them for sale in Germany...

 

[Balle Clorin]

Checking this method for Zenith

Electrical Zenith Setup - Intact Audio

and this is my result with current set up.. did not tune the Zenith yet..
The method:
If the distortion increases by a fair amount (1-2%) rotate the cartridge anti-clockwise from the top and repeat.
If the distortion decreases by a smaller amount then rotate the cartridge clockwise from the top.
repeat steps 3 & 4 until you identify and place a null near the end of the test track which coincides with a typical outer null point.

 

[narud]

im open for input on what im doing wrong or a better test. after seeing the measurements of mp-500's and seeing @ray_parkhurst's pics of a stylus with 630 hours showing a narrow enough contact patch for full frequency response, i decided to pull the trigger on one. its got an estimated 150 hours. microscope pics arent leading me to believe differently.

i recorded the first and last track of an album with the nag and a v15vmr with a few hundred hours on it to compare. on the first track, the nag is down about .5 a db at 15k compared to the shure and about .3 db up at 7.5k. theyre both pretty neutral but dont have exactly the same frequency response so i was expecting some minor differences. on the last track the nag is still up .3db at 7.5k but now its down a full db at 15k compared to the shure. am i wrong expecting the differences to stay the same given the well used mp-500 stylus ray imaged had a narrower contact patch than the microridge at 400 hours that theyre currently testing over at vinylengine? this comparison is showing the same thing that happened last time when i compared my 33ptg and 33sa. the shibata cart looked to be rolling off more at the inner grooves. is this just a flawed comparison?

 

[Balle Clorin]

That drop is tha same as Obray show in their documentation , microridge are superior

 

[Thomas_A]

I think you need to compare up to 40 kHz and take the usual MM HF drop into account. Or use MC to compare stylus types.

 

[narud]

That drop is tha same as Obray show in their documentation , microridge are superior

this is where im getting a bit confused. ive seen that graph orbray has comparing the two stylus types, but then theres the stylus wear pictures ray has been posting.

im not sure if hes registered over her, but this is Luca's mp500 after 630 hours

and heres the vm95l is tracking in the wear study thread


shouldnt the mp500 still be able to provide highs without a drop at the end of the side with its contact patch being that narrow? im still trying to understand how all of this works so im sure theres things im missing and variables im not taking into account.

 

[narud]

I think you need to compare up to 40 kHz and take the usual MM HF drop into account. Or use MC to compare stylus types.

is there something inherent in moving magnet/moving iron/moving coil designs that account for high frequency loss at the end of the side beyond stylus geometry?

 

[JP]

It's just geometry, though there may be aspects beyond wear flat dimensions that contribute.

Also, I'd be very careful in attempting to make wear comparisons based on hours of use. Most papers on the subject stress high variability between copies of styli and the significance of factors beyond the styli themselves, along with the need for enough samples to be tested for statistical significance.

Reading general material on diamond polishing can be quite illuminating in regard to how variable the "hardness" can be, even in "grain oriented" or "single grain" applications.

Last, keep in mind that the examples Ray received were suspect, even the one being tested, and that this test setup is exhibiting ~12dB higher resonance than the previous elliptical tests. That's going to increase wear and contribute to other issues (miss-tracking) that will also increase wear.

 

[Thomas_A]

is there something inherent in moving magnet/moving iron/moving coil designs that account for high frequency loss at the end of the side beyond stylus geometry?

Was thinking of the usual inductance/capacitance and cantilever resonance which cause different results in HF among MM cartridges.

 

[Balle Clorin]

Finally a clear sign on a null point in my search for correct horisontal tracking angle HTA/Zenith

In the 33 rpm VTA/Zenith track on AnalogMagik my main table is improving towards the 120mm null point at the end of the track

 

[GuidoK]

To me it's not quite clear what you're doing. I mean, if I understand correctly this is just 1 measurement. As in 1 hta alignment (not clear which one for that matter), and not a bunch of them (preferably one with a linear tracker too).
So if it's just one measurement, how do you know that you're measuring your system (or hta setting), and not the record?

Also not clear what kind of test signals they are, if the one goes up at 120mm with imd and the other one goes down with imd at 120mm.
And what is V1 and V2? Are they totally different test records with totally different tones/signals? And is 120mm the radius from center or diameter? Because most alignment with the first null point vary between 123mm (radius) and 112mm (radius) but your drawn line in your diagram seems to indicate that the test tracks end at roughly 122mm.

So I have no idea what you're measuring and where you're measuring it

 

[Balle Clorin]

He he quite poor explanation from my side . A copy of another discussion post from what is best forum AnalogMagik thread.

The test is a two tone inter modulation test vs time . Suppposedly suitable for VTA and zenith check , using AnalogMagik software. But the tracks are not vertical mod or horizontal but stereo which makes them less suitable, if not unsuitable.

But I made my own script to analyse the track. The VTA is not changing so we see only the effect if zenith/horisontal tracking variation

You are correct that the record cutting will vary and obscure the actual alignment, It is hard to know what is the record and what is the cartridge contribution. V1 and V2 are different records made for first and second generation Of AnalogMagik. The set includes 33 and 45 rpm records They give different results for the same TT which indicate difference in cutting/pressing , so kind of hard to know what direction to adjust.

But it show that the effect of alignment on IMD % is there even for stereo tracks…I have plots for the CBS STR 112 to , the plots makes it much easier to get a value , rather than looking at a jumping IMD number in REW or other program

The interpretation is that at a given radius/time the IMD is lower and that is when the VTA or Zenith is the same as the record.. but which recor is perfectly correct? None…

The tracks above is from two different records with the same two tone test at different radius.. but combined they seem to make sense , the trend is going the same way at least. Other records are more contradictory ( I had 3 sets and could compare)

See post 2283 above and

Thread 'Setting Zenith/Horisontal Tracking Angle by test record'
https://www.whatsbestforum.com/thre...risontal-tracking-angle-by-test-record.41580/

And in this thread
Post in thread 'Analog Magik'
https://www.whatsbestforum.com/threads/analog-magik.25735/post-1092660

 

[Balle Clorin]

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

Jico SAS-B for Shure V15-iv, I get 29 degrees VTA at 1.25gram VTF so that fits with the above

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

 

[Thomas_A]

Did you ever try shimming the Shure/JICO with some paper bits between headshell and cart to tilt the VTA?

 

[Balle Clorin]

Hardly room for both a Azimuth and VTA shim,, but I will try one day..

 

[Thomas_A]

Hardly room for both a Azimuth and VTA shim,, but I will try one day..

Yes, if you cannot twist headshell or arm for azimuth, then you have a lot of work. My ShureC15V/JICO SAS is at around 25° with shims installed.

 

[GuidoK]

If your ideal VTA is 28deg on the test record, that'll be almost impossible to correct with a normal tonearm vta correction. It's like 4mm per degree so you have to raise the base with 24mm or so (to get to say 22deg...like being 20deg +2deg SRA cutting angle). (most vintage turntables that have VTA control only allow like +/-6mm or so)
Making a custom wedging shim like wallytools does would be more practical I imagine.
Can you see that difference in angle also with a microscope/macrolens when the stylus sits on the record? Can you see it sitting not straight from the side view?

Compared to your at-oc9 the shure/jico one still looks to have quite a bit more IMD on the ideal setting (the scale is not that precise but that AT-OC9 seems to hoover around 0.3% whereas the shure/jico seems to stay well above 0.5%, so that's still about 100% difference, but that could also be in the test record or different wear on the stylii.

 

[ElectricWarrior]

If your ideal VTA is 28deg on the test record, that'll be almost impossible to correct with a normal tonearm vta correction.

I guess it's just misleading that most people call tonearm hight adjustment VTA correction. It's there to level the tonearm. If your VTA or SRA is so bad that it needs fixing, tonearm height will not make enough of a difference. Wedges are the way to go. Or you could try VTF—not as effective as wedges, but more effective than tonearm height.

 

[GuidoK]

Or you could try VTF—not as effective as wedges, but more effective than tonearm height.

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 style 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.