Fun with vinyl measurements

[Balle Clorin]

Thanks Did you you put that in the vote?

 

[morillon]

Your approach removes the following from the equation: the actual levels of what you listen to. I hope the test records are only occasional ;-)
(it's interesting to consider a more serious approach to try and estimate it a little)

Or, here's something our colleagues at AT had incorporated:
;-)

 

[dougi]

Thanks Did you you put that in the vote?

Yep, but it only let me vote once I think. Both in the same vote range though.

 

[Thomas_A]

I just made a simple experiment to look at crosstalk effects. I did so using my Shure V15V + JICO SAS/B. This one has a bit poor crosstalk on the CA-TRS1007 record but not so on the Ortofon test record. Using the files of the CA-TRS1007, I figured that mixing the crosstalk signal with the main signal should give hints whether there is any effect on frequency response and also dynamics. Just playing around but here is the first graph where I just mixed the L channel with the signal from crosstalk that went to the R channel (I know - it should be the other channel ideally but here it is. Blue is the left channel as is, red is left channel mixed with the crosstalk. What can be seen is the phase shifts that adds to the main signal either reducing level or increasing level.

This should ideally be made using the right channel data since it is the right channel crosstalk that pollutes the left channel. I tried with some files I had but realised they must be really synced to work. If it is even possible (will see if possible). Using the left channel crosstalk shows however two things. Phase of the crosstalk rotates and may e.g. explain why there is have a dip in the response below 100 Hz, On the other hand if this is true also for high end, there is a boost due to more in phase addition.

Thoughts?

 

[JP]

Check out https://www.audiosciencereview.com/...esponse-measurement-script.41148/post-2439669

 

[narud]

Shure VN5MR broken cantilever re-attachment

In my collecting of vn5mr's over the years, ive received quite a few broken due to improper packing. This has left me with a few usable broken cantilevers. years ago i sent joseph long one of them to be repaired. he used a small piece of aluminum tube to reattach and bridge the cantilever back together. that particular stylus was a clean break with no missing beryllium. this happened way before i was using the script so my only means of comparison was comparing recordings to a stock stylus. iirc, the repaired stylus was a couple dbs brighter than normal. i ended up selling it since it sounded closer to an audio technica.

after the black diamond cantilever transfer was a success on the other shure i worked on, i figured id try to frankenstein together a stylus with a piece of broken cantilever that still had a good micro ridge and a grip i had laying around with a couple of millimeters of cantilever exposed after a break. in this case, there was a good amount of beryllium length missing. i ended up using 3.5 millimeters of aluminum cantilever from a generic m91 stylus. that was the only thing i had that would slip fit over the beryllium.

im sure the results would have come out better if this was done professionally, but it does work. it needs 1.5 grams to perform as expected on the hifinews 300hz tracks. i dont know if thats because of the stylus assembly, an sra change in my graft or something else. there is now a pretty large high frequency lift and im having a crosstalk issue beyond 14k. im imagining the added weight of the aluminum is causing the lift but im not sure whats causing the super high frequencies leaking into the other channel. maybe the epoxy job? it was pretty tough getting coverage on the slip fit onto the stub that was remaining on the stylus assembly.

either way, it was a fun experiment to try.

View attachment 483314
View attachment 483315View attachment 483316

out of curiosity, i tried this in a solid core v15vxmr body thinking the high end peak would be lower. unexpectedly, it ended up being a db higher.

 

[morillon]

Has anyone here tried a very simple and classic method, sometimes recommended in the 70s, of phase-shifting a channel and observing the antiskating settings (on a 315Hz amplifier, etc.)? Better sound cancellation...


(
Approaches that allowed the general public to make observations and adjustments decades before our widespread use of distortion meters, measurements in IMD, W&F (3kHz/3.15kHz), rumble, etc. Listen to the records/research from the 70s and early 80s...
"Listening"... The idea was to use audible approaches... the origin of many of our tests that we listen to, perhaps not so much anymore....

always interesting to observe
;-)
)

 

[GuidoK]

Has anyone here tried a very simple and classic method, sometimes recommended in the 70s, of phase-shifting a channel and observing the antiskating settings (on a 315Hz amplifier, etc.)? Better sound cancellation...

I've done something similar with a mono record (mono music), inverting 1 channel and adding them ( so a null test). (I'm really more interested in dialing in antiskating on music signal than a single test tone signal as I think that's not really representative for the acutal situation and will give a different result)
But the results of those are just very inaccurate (poor resolution) and therefore pretty useless.
So in a situation with 1.75 antiskating needed (verified with my orsonic skate-o-meter), you only started to hear a significant difference at say antiskating set at 1.0 and at 2.5.
And that was not really measureable in say measuring signal strength of the null signal, but you could hear in the null signal some slightly stronger 'S' sounds and cybal/hihat sounds, so the difference was made where tracking is generally most difficult.

But if you use this method, you get a result like: "when your VTF is set at 1,75gr, the AS should be set somewhere between 1.0 and 2,5. That is not really useful information, anyone can predict an answer like that.
It only shows that a system without antikskating (like an arm on an ar-xa or so) will perform worse on that aspect.
But it's not useful to dial in AS to minimize stylus wear or something like that.
A orsonic/dual skate-o-meter is really the way to go.
The only thing I don't understand is that Dual advises in their service manuals to use a specific dual test record to dial in antiskating with their skate-o-meter, but that test record has silent grooves.
The groove modulation has a significant effect on the occurring skating forces.
Maybe the dual skate-o-meter version performs worse with variable modulation (I don't have that one and have never played with it), as the orsonic one has a completely different design, especially when it comes to how they act at their balance point, which is the most difficult part to read with a variable modulated signal (music)

 

[Balle Clorin]

@GuidoK
It would be really useful if you could use/ post your Orsonic based AS setting needed for 50-100um on the Ortofon test record , and then measure the side force for those settings using a VTF scale on the side. For a given VTF you have . Then the % antiskate of VTF vs modulation will be known to the vinyl world. If you also measure the side force for music track the debate can be settled .

 

[morillon]

I've done something similar with a mono record (mono music), inverting 1 channel and adding them ( so a null test). (I'm really more interested in dialing in antiskating on music signal than a single test tone signal as I think that's not really representative for the acutal situation and will give a different result)
But the results of those are just very inaccurate (poor resolution) and therefore pretty useless.
So in a situation with 1.75 antiskating needed (verified with my orsonic skate-o-meter), you only started to hear a significant difference at say antiskating set at 1.0 and at 2.5.
And that was not really measureable in say measuring signal strength of the null signal, but you could hear in the null signal some slightly stronger 'S' sounds and cybal/hihat sounds, so the difference was made where tracking is generally most difficult.

But if you use this method, you get a result like: "when your VTF is set at 1,75gr, the AS should be set somewhere between 1.0 and 2,5. That is not really useful information, anyone can predict an answer like that.
It only shows that a system without antikskating (like an arm on an ar-xa or so) will perform worse on that aspect.
But it's not useful to dial in AS to minimize stylus wear or something like that.
A orsonic/dual skate-o-meter is really the way to go.
The only thing I don't understand is that Dual advises in their service manuals to use a specific dual test record to dial in antiskating with their skate-o-meter, but that test record has silent grooves.
The groove modulation has a significant effect on the occurring skating forces.
Maybe the dual skate-o-meter version performs worse with variable modulation (I don't have that one and have never played with it), as the orsonic one has a completely different design, especially when it comes to how they act at their balance point, which is the most difficult part to read with a variable modulated signal (music)

Ultimately, it was mostly the very demanding, difficult-to-reproduce "classical" piano recordings that were used for adjustments and checks... VTF, anti-skating in mono, and of course W&F.... The idea here is also to look towards the end result... the music and a more evident audibility....

 

[morillon]

"I you also measure the side force for music track the debate can be settled ."

Nosens

The "music" isn't limited to DR 3/6...

;-)

 

[GuidoK]

It would be really useful if you could use/ post your Orsonic based AS setting needed for 50-100um on the Ortofon test record , and then measure the side force for those settings using a VTF scale on the side. For a given VTF you have . Then the % antiskate of VTF vs modulation will be known to the vinyl world. If you also measure the side force for music track the debate can be settled .

I can only post a 50µm with confidence.
A side force checker is a bad tracker, although it has a line contact stylus (the 1L at least). (there's no suspension latereally so no damping)
I'm not gonna track higher excursions as I'm afraid it might damage the device. Obviously it doesn't amplify (it's not a cartridge), but to the ear it almost sounds like it might already be mistracking above 50µm (I once did a 70µm and the sound coming from the stylus didn't gave me a lot of confidence). 50µm gave me 18%vtf and 70µm gave me almost 20% vtf (19,7%), but I can't verify if this value is correct. (this is on my dual 721 so with 25deg offset angle if you want to work out the friction coefficient to transpone this value up to other tonearms)
These values were measured at 1,75g VTF with the 1L (so the line contact skate o meter version)
With mistracking who knows what values you get and whether or not they're right (I expect them to be potentially higher than non mistracking)
I also don't really see the point of measuring at those high excursions at a single tone; it has nothing to do with music levels and frequencies where the antiskating should be set.
Antiskating is imho a pretty big rabbithole for engineers that expect one value to be correct
What matters most is that you're somehwat in the correct region and not way off. So if you're at 11% vtf, 13% vtf or 15% vtf, that's all correct. Just don't be at considerably higher or lower to that range. In that sense, measuring silent grooves would be more useful than those high modulated test tracks.
And measuring sessions at differnt VTF would also be more useful I think. In the past I've done that for 2 music tracks.
That looked like this: (sorry, I used my native language in this spreadsheet)

Here you can see that the correct amount of AS force also isn't 100% constant across the vtf range. Lower VTF tends to need lower AS percentage wise.
However I don't know how much bearing stiction (or other phenomena that I don't know/understand yet) is messing up these results. When measuring the antiskating force with my scale setup, I need to take those measurements in such a way that I have the tonearm bumping against the scale sensor, so a motion so to speak. If I rest my arm against the sensor and just gradually turn up the antiskate, the results are just very irratic. Antiskating is just a big rabbithole because the forces are so low.

 

[GuidoK]

BTW does anyone have a system (based on measurements) to determine what the ideal VTF is for a cartridge?
And does that yield repeatable results?

 

[Balle Clorin]

I have this Cleararudio record with a 15 minute mono 3150hz track, and thought it would show the expected tracing distortion across the record. -two minima and 3 peaks..

One manual test gives this result,distortion vs position

An automated python script gives me this,, distortion vs time.. Not exactly what I am hoping for, is my HTA so far off??
With antiskate on

some random files I had

 

[Thomas_A]

HTA distortion drowns in remaining distortion. Can you script the L-R phase diff?

 

[Balle Clorin]

phase difference.. her we go L R distortion on top, phase difference below

another very cheap turntable and AT95E

 

[Thomas_A]

One cross zero but never goes up again , about 5 degree diff total, the 95E shows a parabolic shape but is positive all the way, and 2 degree diff total.

Don’t know what it means in terms of zenith or HTA someone did this however.

Tonearm tracking error and distortion

In the last posting, I reviewed the math for calculating the tracking error for a radial tonearm. The question associated with this is “who cares?” In the March, 1945 issue of Electroni…

www.tonmeister.ca

 

[dennis h]

One cross zero but never goes up again , about 5 degree diff total, the 95E shows a parabolic shape but is positive all the way, and 2 degree diff total.

Don’t know what it means in terms of zenith or HTA someone did this however.

Tonearm tracking error and distortion

In the last posting, I reviewed the math for calculating the tracking error for a radial tonearm. The question associated with this is “who cares?” In the March, 1945 issue of Electroni…

www.tonmeister.ca

thanks for the above Thomas...

 

[Thomas_A]

phase difference.. her we go L R distortion on top, phase difference below
View attachment 489428





another very cheap turntable and AT95E

View attachment 489432

Have you measured the tonearm pivot to centre of the turntables as well?

Tonearm alignment and tracking error

The June 1980 issue of Audio Magazine contains an article written by Subir K. Pramanik called “Understanding Tonearms”. This is a must-read tutorial for anyone who is interested in the …

www.tonmeister.ca

 

[Balle Clorin]

Nice article . The first phase plot is from my SME V . Values virtually same as in article Donot have a Feickert protractor but pivot to spindle is 215 mm using a ruler. - error introduced by angle would be less distance. Set up arm using SME sjablong for sliding base.

The second plot is a Sony PS212, set but using Tonearm collar to tip if xx specified mm, looks OK on project protractor disk.