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Phonograph Stylus Wear Experiment

morillon

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maybe you should to obtain finer observations, fft thd l and r 192/24, observe just one fixed frequencie..
15khz (or 20khz)at velocities that are not too high, such as 3.54cm or less, so as not to be confronted with the wear of the test disc...
(see coupling with an imd test?..)
fast and easy with virtins multitone or rew...

realize under these conditions times be possible to increase the number of measurements at constant numbers of hours (50 or 100 ?)
(observing the distortion is somewhere "the finality". and in addition a very controlled and quantified measurement)
 
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Balle Clorin

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Truly exiting times ahead for objective vinylists, keep up the good work:)

By the way , what is the 45 degree method when taking cartridge photos?
 
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USER

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Truly exiting times ahead for objective vinylists, keep up the good work:)

By the way , what is the 45 degree method when taking cartridge photos?
Geez, the thread is so long I don't know where I first read it.


My first attempts:


But Ray recently joined ASR and begins to discuss his methods in the thread he just created:

 

Cwopete5

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This is good controlled approach to finally providing some tangible data to support stylus wear figures from phono cartridge manufacturers.

Based on your impeccable test regime, your results may not necessarily reflect real-world customer expectations. For example, I just finished cleaning the album I am listening to at this very moment (Yes - Fragile) in my Spin Clean Record Washer MK II and dried it with a lint-free cloth provided in the kit. I then cleaned the stylus of my AT-VM95SH stylus with a brush. I don't always water-wash my records every time I listen to them. In between washings I use a carbon fiber brush for Turntable Labs to remove any dust before playing. I do brush the stylus after I play every album and once a week use the Audio Technics Stylus Cleaner solvent. I would consider myself an average listener with a modest turntable set up. I don't use a play-time counter but I do switch cartridge head shells every couple of months to get a different sound. Current inventory is the AT-VM95SH I just mentioned, a Goldring E3 and an Ortofon 2M Blue. Overhang is set to 52 mm for all three and VTF set to manufacturers specs and verified with a calibrated digital scale. I use a standard set of alignment tools from Hudson HiFi. Nothing too fancy but it gets the job done.

The proposed test approach of repeatedly playing of the same record for extended periods of time without cleaning the record surface or stylus may actually produce greater stylus and record wear than what could be expected with real-world users like myself. I'm not certain how you could overcome this difference over than provide a caveat within the test results or possible run a micro test in parallel to see if there are any tangible deltas between the two outcomes. Either way, I think you are off to an outstanding start and I will be eagerly watching your progress. Greatly appreciate what you're doing here.

IMG_6038.jpeg


IMG_6037.jpeg


IMG_6040.jpeg
 
OP
B

BendBound

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@Cwopete5,​

You bring up some good points. We know, believe me when I say we have examined all elements of our experiment. Our play of a record is only one side for 12 hours, then some cleaning is done, then on to the next side for another 12 hours of log. @BMRR will conduct that test and record bits of vinyl to help us get to evolution in THD on the stylus and later on record wear from a worn stylus.

Ray has already done one test using the same lp for actually over 1,000 hours, but on a linear TT and low VTF. That test produced very long hours of play with little wear to either the stylus tip or the record, according to simply listening by Ray.

Now we have a more ambitious test, closer to real like, but as you point out, not precisely.

Our goals we hope are straightforward: 1) evaluate change in TDH as the stylus wears, if any, and 2) look for evidence of stylus damage on the records correlated to progressive stylus tip wear.

We are planning on doing recordings, posting those in such a way that folks here can evaluate them using software to identify what is apparent, as our experiment moves toward critical stylus wear as manifest at a minimum on photomarcographic images. Those images will be posted in real time, as will be 44.1kHz or 96kHz/24 bit captures. We can capture from a new record a snippet to begin the test since we have one, and later capture the same track for followup changes. We can reserve that record for the end when we likely complete 12 hours on both its sides.

We have the CBS STR-100 laboratory test record, also sealed. It would be good to know now from this community what track(s) to capture as we begin the test. We can use this same record to record the same suggested track(s) on our hour intervals as noted in the initial post (i.e., 0hrs (i.e., the new stylus), 48hrs, 96hrs, 240hrs, 360hrs, and 480hrs, with timing adjusted based on observations).

What we are trying to achieve is a bench experiment, and we plan to use our experiences here to frame future stylus wear tests.
 
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BendBound

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maybe you should to obtain finer observations, fft thd l and r 192/24, observe just one fixed frequencie..
15khz (or 20khz)at velocities that are not too high, such as 3.54cm or less, so as not to be confronted with the wear of the test disc...
(see coupling with an imd test?..)
fast and easy with virtins multitone or rew...

realize under these conditions times be possible to increase the number of measurements at constant numbers of hours (50 or 100 ?)
(observing the distortion is somewhere "the finality". and in addition a very controlled and quantified measurement)

The cartridge manufacturer JICO uses the 15kHz benchmark to suggest that once THD at that frequency reaches 3%, its time to think about replacing the stylus tip. Of course, the problem is that most humans older than 40 cannot hear that frequency as seen here, Absolute Threshold Of Human Hearing and Human Hearing Range. Even if they could, its unlikely they are trained well enough to sort out a 15kHz signal. Regardless, many vinylphiles claim they hear zero distortion from a worn stylus or from a record well into thousands of hour of use. So from that perspective, the 15kHz threshold (or even 8 to 10kHz) requires the kind of measurements performed on Python or some other software program. We know numerous folks here are experts on that program.

We used already a Tascam DA-3000 to capture three side of vinyl (two of the same title on two copies of the record) at 96kHz/24 bit. Our turntable operator has the ability to record also at 96kHz/24bit. He will be capturing most of the samples, likely by playing sections of a now sealed copy of Technical Series Professional Test Record LP Vinyl CBS Laboratories STR-100. We intend to operate with two copies.

Knowing the track to record from this community would be useful, so if you wish to weigh in, please do. We also know that repeated play of a single track with a progressively worn stylus will degrade the vinyl of the test record. Those the second copy. I expect for baseline, both copie need that selected track to be recorded first as new vinyl. That way, calibration of the two but same tracks can be achieved. If some other procedure is advised, please again mention it in response here.

As far as sampling frequency, the routine noted above is not as you say linear. Ray Parkhurst who is doing the photomacrographic imaging believes this schedule will show indicative and progressive wear on the stylus tip. That does not mean we are locked in on the same sampling schedule for audio tracks, something I will bring up to the team.

Our main goal is to see in successive photomacrographic images the progressive wear on the stylus on a known hourly basis. We also want to see wear on vinyl, and Ray has gained insights into how to do that. Please see this link on Vinyl Engine in Stylus Evaluation Imaging thread: By ray_parkhurst » 23 May 2023 10:09.
 
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morillon

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if the signal is not too high velocity ... even at 15k it should not be too "using"
on the other hand if you are a little at the limit in capture at 96k...
for 15k..ok f*3 45k ..but you can't observe observe at f*4 f*5...
i know..it seems like a lot...but good for a thd.. not that much..
at 20k...96k won't even pass f*3 etc...
explain my advice as a precaution to go to 192k...

maybe would be good to look if not two or 3 copies of a 6605....
in fixed frequencies ... etc (from memory in 3.54)
 

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Knowing the track to record from this community would be useful, so if you wish to weigh in, please do.
As I have already told you in our private messages, it is the first track. It is comprised of two sweeps, one each of the left and right channels. I'd advise you record the whole thing in case the right channel becomes useful. It can help you see if your channel balance and this set-up is way off, though don't rely on it for channel balance measurements. Please make sure to go over my notes and the instructions on the script thread carefully.
 

morillon

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a capture in fixed frequencies like 10k-15k(-20k) in thd with rew multitone or virtins etc allows fast ,realtime , efficient and simple measurements.
some discs like the 6605 ( another ? ) offer it easily (see the 30k with 6605)

or classically imd... ? 2 tons , (or 3 tons like the last shure 200-2100-17k)
 
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Thomas_A

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The cartridge manufacturer JICO uses the 15kHz benchmark to suggest that once THD at that frequency reaches 3%, its time to think about replacing the stylus tip. Of course, the problem is that most humans older than 40 cannot hear that frequency as seen here, Absolute Threshold Of Human Hearing and Human Hearing Range. Even if they could, its unlikely they are trained well enough to sort out a 15kHz signal. Regardless, many vinylphiles claim they hear zero distortion from a worn stylus or from a record well into thousands of hour of use. So from that perspective, the 15kHz threshold (or even 8 to 10kHz) requires the kind of measurements performed on Python or some other software program. We know numerous folks here are experts on that program.

We used already a Tascam DA-3000 to capture three side of vinyl (two of the same title on two copies of the record) at 96kHz/24 bit. Our turntable operator has the ability to record also at 96kHz/24bit. He will be capturing most of the samples, likely by playing sections of a now sealed copy of Technical Series Professional Test Record LP Vinyl CBS Laboratories STR-100. We intend to operate with two copies.

Knowing the track to record from this community would be useful, so if you wish to weigh in, please do. We also know that repeated play of a single track with a progressively worn stylus will degrade the vinyl of the test record. Those the second copy. I expect for baseline, both copie need that selected track to be recorded first as new vinyl. That way, calibration of the two but same tracks can be achieved. If some other procedure is advised, please again mention it in response here.

As far as sampling frequency, the routine noted above is not as you say linear. Ray Parkhurst who is doing the photomacrographic imaging believes this schedule will show indicative and progressive wear on the stylus tip. That does not mean we are locked in on the same sampling schedule for audio tracks, something I will bring up to the team.

Our main goal is to see in successive photomacrographic images the progressive wear on the stylus on a known hourly basis. We also want to see wear on vinyl, and Ray has gained insights into how to do that. Please see this link on Vinyl Engine in Stylus Evaluation Imaging thread: By ray_parkhurst » 23 May 2023 10:09.
I followed @ray_parkhurst interesting wear experiment at the time, and the HF loss was there but tiny. Looking at his LP wear picture, it does not look like a normal stylus would have caused that, due to its limited contact patch. There is a chopping pattern that goes well to the top of the groove. Perhaps a very worn or chopped stylus or mistracking. Wear is usually visually seen as a stylus trace at mid-distance of the groove and that the fine HF modulations are worn down, effectively loosing level.

Comparison of the 1-2 dB HF loss of Rays experiment, blue is the "worn" record. There was no effect looking at new and old stylus.

test%20left%20ch.gif
 
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ray_parkhurst

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I followed @ray_parkhurst interesting wear experiment at the time, and the HF loss was there but tiny. Looking at his LP wear picture, it does not look like a normal stylus would have caused that, due to its limited contact patch. There is a chopping pattern that goes well to the top of the groove. Perhaps a very worn or chopped stylus or mistracking. Wear is usually visually seen as a stylus trace at mid-distance of the groove and that the fine HF modulations are worn down, effectively loosing level.

Comparison of the 1-2 dB HF loss of Rays experiment, blue is the "worn" record. There was no effect looking at new and old stylus.

I think this was the case since there was very little wear on the stylus at 500hrs, and it was just barely broken-in IMO at 1000hrs, so I would not expect a lot of degradation.

With many more records being played, I'm expecting more and faster wear, and it will interesting to see how that correlates to both THD and record wear.
 

Cwopete5

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Regardless, many vinylphiles claim they hear zero distortion from a worn stylus or from a record well into thousands of hour of use.
I just replaced a badly worn out elliptical stylus. The reason I knew it was shot:
  1. When lowering the cartridge onto the record, the stylus was having trouble catching the first groove, just making some scratchy noise. I'm sure that did some damage.
  2. Inner groove distortion became very obvious.
  3. The usual clarity was gone and it sounded "fuzzy".
Unfortunately I don't have any way of seeing how bad the stylus really was worn. I doubt it had more than 500 hours on it. So it was more than just the sound that cued me into the stylus being worn out.

I'd say anyone who says they're hearing zero distortion from a worn out stylus likely has worn out ears as well!
 

ray_parkhurst

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I just replaced a badly worn out elliptical stylus. The reason I knew it was shot:
  1. When lowering the cartridge onto the record, the stylus was having trouble catching the first groove, just making some scratchy noise. I'm sure that did some damage.
  2. Inner groove distortion became very obvious.
  3. The usual clarity was gone and it sounded "fuzzy".
Unfortunately I don't have any way of seeing how bad the stylus really was worn. I doubt it had more than 500 hours on it. So it was more than just the sound that cued me into the stylus being worn out.

I'd say anyone who says they're hearing zero distortion from a worn out stylus likely has worn out ears as well!
If you still have that stylus, I'd be happy to image it to see how worn it is.
 

morillon

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(

thinking a bit...
I apologize for having forgotten that if personally I imagine that the observation of a simple thd at 15k for example will allow a sufficiently tangible measurement...
the real question remains to associate this measurement with the subjective appreciation of wear.
and then we come back to a bottomless well...

it is the subjective approach that is the real difficulty...

ps
I will see if a sufficiently curious friend, not old, demanding and listening to a lot of type of music (on very neat and very well cleaned discs) accepts that I now quickly measure his editing (new cartdrige with just a few tens of hours)... and the days when this expensive cartdrige has several thousand euros, very recent, he will be, to his ears, tired... that is interesting...

all the more interesting since like a lot of friends around me using very expensive mc cells.. he has the culture of the hour meter..

but you will have to be patient... very
because he's not going to intensify his use of lp for that..
hihi
;-)

)
 

Thomas_A

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I think this was the case since there was very little wear on the stylus at 500hrs, and it was just barely broken-in IMO at 1000hrs, so I would not expect a lot of degradation.

With many more records being played, I'm expecting more and faster wear, and it will interesting to see how that correlates to both THD and record wear.
Nice to see you here Ray. Your pictures are really amazing. Did you continue the investigation the wear and 3D rendering of the grooves?
 

ray_parkhurst

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Nice to see you here Ray. Your pictures are really amazing. Did you continue the investigation the wear and 3D rendering of the grooves?
I am still dabbling with how best to do the groove photos. It's an interesting problem to shoot a tiny area of a large object.

For folks who have not seen it, I've started a thread on groove imaging here:

 

LTig

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The cartridge manufacturer JICO uses the 15kHz benchmark to suggest that once THD at that frequency reaches 3%, its time to think about replacing the stylus tip. Of course, the problem is that most humans older than 40 cannot hear that frequency as seen here, Absolute Threshold Of Human Hearing and Human Hearing Range.
I seriously doubt that any human being is able to hear 15 kHz harmonic distortion at any level because even the first harmonic (f2) is at 30 kHz and hence far above human audibility.

However measuring 15 kHz THD is not straight forward either. You need a preamp which follows the RIAA deemphasis curve far above 20 kHz (until 45 kHz for f2 and f3, and higher for the higher harmonics). This is not a given as it depends on the design of the gain stages. A typical single opamp based non inverting gain stage with active RIAA cannot have less gain than 1 (0 dB) and hence has more gain than RIAA requires above a certain frequency. The harmonics above this frequency then are amplified too much and will lead to higher measured THD as there really is. I'm not sure how relevant this is for your tests but you should measure FR of your phono preamp to make sure it leads to proper THD results.
 

ray_parkhurst

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The curves of H2 and H3 from a swept measurement should tell us if the system is reproducing the harmonics with reasonable fidelity. Ultimately we may not be able to trust the absolute values of H2 above a 10kHz fundamental, and H3 above a ~6kHz fundamental, but if the curves look reasonable we may be able to trust deltas in the readings versus wear. In any event, we'll have the data available for analysis and interpretion.
 
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