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Phonograph Stylus Wear Experiment

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BendBound

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Update on the stylus wear experiment since we want to be as transparent has possible.

We have moved from T0 to T24 on wear hours for the stylus on the Audio Technica VMN95E phono cartridge. The removable stylus is en route to be photomacrograph imaged by @ray_parkhurst for the second time, at T24 or 24 hours. For completeness, the cartridge was properly aligned by @BMRR (Vinyl Engine) as well as possible with his tools using a Sanyo jig (Stevenson), double checked on alignment, dialed in on a Sanyo Q50 Plus turntable for VTF, SRA, and azimuth. An initial image of this elliptical stylus showed it’s tip was perfect, no zenith error. To maintain the alignment, the cartridge will not be removed from its OEM head shell until the entire experiment is completed.

We designed this experiment to monitor progressive physical wear of a diamond stylus tip. The worn stylus will be documented by successive photomacrographic images in discreet time intervals. We want this experiment to be as American composer Aaron Copland would write it in 1942, Fanfare for the Common Man. Stereophile’s pages are packed with turntables, phono cartridges and phono preamps that the common man or woman cannot afford. So our experiment employs equipment folks can afford. The point is to offer visual results that 99% of our buddies can appreciate. I’ve seen my friend's systems. The local stereo shops do not have imaging equipment, such as a suitable microscope. Yet folks can appreciate what a worn stylus tip looks like by hours of use, especially if shown in a set of images revealing that evolution from a new stylus to a seriously worn one. Therefore, @BMRR’s system is simply wearing out a stylus on clean, mostly VG++ to mint records.

Nonetheless, attendant with physical diamond tip stylus wear we also wanted to see if we could measure progressive change in total harmonic distortion (THD) or any distortion. JICO, a major cartridge manufacturer, states that a stylus needs to be evaluated for replacement once THD reaches 3% at some high frequency (15kHz±). That company has published data on various styli lifespans based on hours of play, all referenced to 3% measured THD. My buddies can’t identify a 3% threshold THD. So our experiment incorporates making successive 96/24 recordings of a CBS test record at various wear time points, coupled with imaging of the stylus tip at the same intervals.

Based on feedback from several folks on ASR in regard to evaluating THD using a complex developed program with little documentation we understand that supporting analytical work requires tight protocol and numerous copies of NOS test records to even have a chance of seeing the kind of sonic degradation that JICO states. Moreover, the recordings need to use very good and well-calibrated equipment, ideally recordings on pro gear at 192kHz/24 to see 2nd and 3rd harmonics. A 96/24 dub will at least show the 2nd harmonic, but its less than ideal. Finally, the cartridge needs to be nearly perfectly aligned, verified by use of several other test records. From my experience, except for cartridge manufacturers or audio labs, perhaps only a handful on ASR or Vinyl Engine can use a THD marker to evaluate a worn stylus. Folks don't have the gear, programs or the expertise. Even my buddies do not set up their turntables with anywhere near the level of precision required for measuring THD as describe here. We still wanted to explore this angle of stylus wear. We attempted to close this gap by securing NOS test records. Yet we likely do not have the necessary equipment with sufficient precision to reliably measure the evolution in THD if that is essential here.

We absolutely will have a reference point at T0. Our recordings may be deemed inadequate for precision analysis based on feedback from folks on ASR. Nonetheless, we intend to use the same gear to record at T0, T24, T48, T96, T192, T288 and so on, until critical wear is achieved. We expect also to see progressive change on each of these future CBS test record recordings. If our process proves to be inadequate, we will learn from it and apply that to our next experiment. That will be to take a Shibata stylus tip to critical wear. But this is where we are now. This is after all our experiment designed from the beginning to document physical wear of a diamond stylus tip.

We have already laid out our protocol for this experiment. But to be complete, all successive recordings of a NOS CBS STR-100 test record will be made through this setup: Audio-Technica VM95E cartridge ⇒ Sanyo PLUS Q50 stock original head shell and tonearm wires ⇒ Sanyo PLUS Q50 stock original hardwired RCA-type audio output cables ⇒ U-Turn Pluto phono preamp ⇒ Monoprice 3-foot RCA-to-1/8th-inch stereo cable ⇒ ZOOM H1n recorder ⇒ Recorder set to WAVE mode, 24 bits, 96 kHz ⇒ Recording onto SanDisk Extreme PLUS microSDHC card ⇒ WAVE files uploaded directly to Google Drive straight from the card.

No EQ, except for the RIAA equalization built into the U-Turn Pluto phono preamp. The U-Turn Pluto preamp is MM only, and has no user configurable settings. Input capacitance: 100 pF. Input impedance: 47,000 Ohms. Gain: 36 dB. RIAA accuracy: within +/- 0.2 dB. According to U-Turn, the preamp has a rumble filter intended to filter out turntable bearing noise and warped record noise (“rumble") below 20 Hz.

We don’t know the capacitance of the turntable’s audio output cables, but most turntables built in the late 1970s had low capacitance cables because CD4 quadraphonic records were still relatively popular, so we've assumed these cables are around 100 pF to 150 pF, which was typical then. The instruction manual and the service manual don’t specify, unfortunately. Nonetheless, total line input capacitance is assumed to be ~225 pF,

See below charts showing the recorded signal from the Audio Technica VMN95E phono cartridge though the system at T0.

Phono Cartridge Wear Test - VMN95E - Sanyo PLUS Q50 - ZOOM H1n - 0 Hours - 1.png

Phono Cartridge Wear Test - VMN95E - Sanyo PLUS Q50 - ZOOM H1n - 0 Hours - 4.png

The CBS STR-100 audio recordings were also made available on Vinyl Engine. Board mail comments from @spunkerboybr to @BMRR regarding the initial CBS STR-100 recording at T0 are as follows:

Back onto the test now: the files came through easily, and all the recordings are fine. The Zoom H1n is definitely working at 24-bit/96kHz, as I can see ultrasonic content and 24-bit resolution by inspecting the samples. Volume is fine as well.

The VM95E seems to be pretty good with its as-new performance. I've given a rough check on the sweep test and the overall results seem pretty nice for a bonded elliptical at first glance. Definitely a good evidence that the stylus is in good shape, that everything was carefully set up (I wouldn't expect anything different from you!).


We are looking for someone to assist us by creating similar charts for the remainder of our experiment. We will not know if this tactic works until comparative analysis is performed on the sequence of test record recordings beginning with T0 here. We might be surprised; this approach may work.

Our next imaging and recording point is T24, followed by T48 and T96 and so on until we have achieved critical stylus wear.
 
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ray_parkhurst

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So it appears the cartridge/stylus is showing a peak of ~10% H2 at ~6kHz on blue channel, and ~5% at 15kHz on orange channel. FR is -5dB at 20kHz on red channel.
 

JP

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Is there a TLDR version?
 
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BendBound

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Is there a TLDR version?
Message received:

While, our primary goal is to show progressive physical wear on the phono stylus tip, our secondary objective is to detect changes in total harmonic distortion at the same sampling interval. The stylus wear experiment has reached its second imaging point at 24 hours. Images will be posted shortly. Attendant with stylus imaging, are recordings of a CBS test record, Side A Track 1. T0 frequency sweeps have been posted. We will post the T24 recording relatively soon, we hope someone here will post the frequency sweep, similar to that shown above. While we don't have a pro kit to record the test record, we expect that progressive change will be evident in THD as the experiment moves on.
 
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JP

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I thought the test record files were going to be made available?
 
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BendBound

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I thought the test record files were going to be made available?
They are. The first one dropped (T0) in a post I made on July 14, Friday at 3:11 PM. See it at the bottom of the page. You have to expand the post to see it.

Not sure how I messed up that post, but somehow I embedded my response to @Digby within his inquiry. If ASR has a site moderator, perhaps they would be willing to clean that up.
 
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Icewater_7

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When you get back from vacation, could you do a private transfer of the whole set of digital files the way we have been doing for music sharing? I’d like to do some analysis with some of my software tools for curiosity sake.
 

morillon

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Update on the stylus wear experiment since we want to be as transparent has possible.

We have moved from T0 to T24 on wear hours for the stylus on the Audio Technica VMN95E phono cartridge. The removable stylus is en route to be photomacrograph imaged by @ray_parkhurst for the second time, at T24 or 24 hours. For completeness, the cartridge was properly aligned by @BMRR (Vinyl Engine) as well as possible with his tools using a Sanyo jig (Stevenson), double checked on alignment, dialed in on a Sanyo Q50 Plus turntable for VTF, SRA, and azimuth. An initial image of this elliptical stylus showed it’s tip was perfect, no zenith error. To maintain the alignment, the cartridge will not be removed from its OEM head shell until the entire experiment is completed.

We designed this experiment to monitor progressive physical wear of a diamond stylus tip. The worn stylus will be documented by successive photomacrographic images in discreet time intervals. We want this experiment to be as American composer Aaron Copland would write it in 1942, Fanfare for the Common Man. Stereophile’s pages are packed with turntables, phono cartridges and phono preamps that the common man or woman cannot afford. So our experiment employs equipment folks can afford. The point is to offer visual results that 99% of our buddies can appreciate. I’ve seen my friend's systems. The local stereo shops do not have imaging equipment, such as a suitable microscope. Yet folks can appreciate what a worn stylus tip looks like by hours of use, especially if shown in a set of images revealing that evolution from a new stylus to a seriously worn one. Therefore, @BMRR’s system is simply wearing out a stylus on clean, mostly VG++ to mint records.

Nonetheless, attendant with physical diamond tip stylus wear we also wanted to see if we could measure progressive change in total harmonic distortion (THD) or any distortion. JICO, a major cartridge manufacturer, states that a stylus needs to be evaluated for replacement once THD reaches 3% at some high frequency (15kHz±). That company has published data on various styli lifespans based on hours of play, all referenced to 3% measured THD. My buddies can’t identify a 3% threshold THD. So our experiment incorporates making successive 96/24 recordings of a CBS test record at various wear time points, coupled with imaging of the stylus tip at the same intervals.

Based on feedback from several folks on ASR in regard to evaluating THD using a complex developed program with little documentation we understand that supporting analytical work requires tight protocol and numerous copies of NOS test records to even have a chance of seeing the kind of sonic degradation that JICO states. Moreover, the recordings need to use very good and well-calibrated equipment, ideally recordings on pro gear at 192kHz/24 to see 2nd and 3rd harmonics. A 96/24 dub will at least show the 2nd harmonic, but its less than ideal. Finally, the cartridge needs to be nearly perfectly aligned, verified by use of several other test records. From my experience, except for cartridge manufacturers or audio labs, perhaps only a handful on ASR or Vinyl Engine can use a THD marker to evaluate a worn stylus. Folks don't have the gear, programs or the expertise. Even my buddies do not set up their turntables with anywhere near the level of precision required for measuring THD as describe here. We still wanted to explore this angle of stylus wear. We attempted to close this gap by securing NOS test records. Yet we likely do not have the necessary equipment with sufficient precision to reliably measure the evolution in THD if that is essential here.

We absolutely will have a reference point at T0. Our recordings may be deemed inadequate for precision analysis based on feedback from folks on ASR. Nonetheless, we intend to use the same gear to record at T0, T24, T48, T96, T192, T288 and so on, until critical wear is achieved. We expect also to see progressive change on each of these future CBS test record recordings. If our process proves to be inadequate, we will learn from it and apply that to our next experiment. That will be to take a Shibata stylus tip to critical wear. But this is where we are now. This is after all our experiment designed from the beginning to document physical wear of a diamond stylus tip.

We have already laid out our protocol for this experiment. But to be complete, all successive recordings of a NOS CBS STR-100 test record will be made through this setup: Audio-Technica VM95E cartridge ⇒ Sanyo PLUS Q50 stock original head shell and tonearm wires ⇒ Sanyo PLUS Q50 stock original hardwired RCA-type audio output cables ⇒ U-Turn Pluto phono preamp ⇒ Monoprice 3-foot RCA-to-1/8th-inch stereo cable ⇒ ZOOM H1n recorder ⇒ Recorder set to WAVE mode, 24 bits, 96 kHz ⇒ Recording onto SanDisk Extreme PLUS microSDHC card ⇒ WAVE files uploaded directly to Google Drive straight from the card.

No EQ, except for the RIAA equalization built into the U-Turn Pluto phono preamp. The U-Turn Pluto preamp is MM only, and has no user configurable settings. Input capacitance: 100 pF. Input impedance: 47,000 Ohms. Gain: 36 dB. RIAA accuracy: within +/- 0.2 dB. According to U-Turn, the preamp has a rumble filter intended to filter out turntable bearing noise and warped record noise (“rumble") below 20 Hz.

We don’t know the capacitance of the turntable’s audio output cables, but most turntables built in the late 1970s had low capacitance cables because CD4 quadraphonic records were still relatively popular, so we've assumed these cables are around 100 pF to 150 pF, which was typical then. The instruction manual and the service manual don’t specify, unfortunately. Nonetheless, total line input capacitance is assumed to be ~225 pF,

See below charts showing the recorded signal from the Audio Technica VMN95E phono cartridge though the system at T0.

View attachment 299982
View attachment 299983
The CBS STR-100 audio recordings were also made available on Vinyl Engine. Board mail comments from @spunkerboybr to @BMRR regarding the initial CBS STR-100 recording at T0 are as follows:

Back onto the test now: the files came through easily, and all the recordings are fine. The Zoom H1n is definitely working at 24-bit/96kHz, as I can see ultrasonic content and 24-bit resolution by inspecting the samples. Volume is fine as well.

The VM95E seems to be pretty good with its as-new performance. I've given a rough check on the sweep test and the overall results seem pretty nice for a bonded elliptical at first glance. Definitely a good evidence that the stylus is in good shape, that everything was carefully set up (I wouldn't expect anything different from you!).


We are looking for someone to assist us by creating similar charts for the remainder of our experiment. We will not know if this tactic works until comparative analysis is performed on the sequence of test record recordings beginning with T0 here. We might be surprised; this approach may work.

Our next imaging and recording point is T24, followed by T48 and T96 and so on until we have achieved critical stylus wear.
in the end, what antiskating adjustment bias was adopted?
this is the main source of dysimetric wear often heavily observed by re-tip and manufacturers ....... the subject which can only be without a real solution remains a compromise that can be constantly discussed
 

ray_parkhurst

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I've been running LT for so long that I've forgotten about the impact of AS on sonic performance. Other than increased wear on one channel or the other, what impact does AS have on sonics? Is it possible to set proper AS simply by measurement of a test record, and what objective parameters would be affected/optimized by AS adjustment? Is it possible to determine from the STR100 recording at T0 if the AS is set correctly?
 

Icewater_7

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I've been running LT for so long that I've forgotten about the impact of AS on sonic performance. Other than increased wear on one channel or the other, what impact does AS have on sonics? Is it possible to set proper AS simply by measurement of a test record, and what objective parameters would be affected/optimized by AS adjustment? Is it possible to determine from the STR100 recording at T0 if the AS is set correctly?
BendBound and I both use a commercial vinyl record (Johnny Winter, “2nd Winter”) to check and adjust for AS because it has a blank 4th side. I’m not adjusting for AS specifically because my arm is a linear tracking type with a near frictionless compressed air bearing (Eminent Technology ET-2A). After setting up my table with a bubble level so the platter is level right angles to the arm tracking direction, I adjust the table so the stylus has zero motion front/back in the tracking direction when needledropped into the blank record side. My TT has an excellent clamp to get the vinyl very flat against the platter. I know the best way to adjust for azimuth is with an o-scope but I didn’t care to buy a used one just for that. Finally, a test record came on line that allowed me to test and adjust for that (Analog Productions (“The Ultimate Analog Test LP”). Two tracks contain 1kHz tones only on each channel so I digitally record them with a tight 1kHz bandpass filter, de-click the files, and tweak my azimuth adjustment on the arm until I get tightly matched crosstalk RMS levels between L&R. Spent about 3 days to get equal channel levels into my A2D converter inputs and azimuth crosstalk matched to within 0.3dBFS. Not a fun exercise. Can’t scientifically say the audio was improved on my LP digital recordings from then on, but it did give me peace of mind that my setup was proper and less likely to impart extra wear on my stylus.
 

Balle Clorin

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Is the FR plot in post 181 made with the correct EQ? Seem strange in the low end,,,,
 

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Is the FR plot in post 181 made with the correct EQ? Seem strange in the low end,,,,
It's strange at the top end as well, lol. I've never seen an Audio-Technica cartridge like this and would not expect what is the defacto standard option to behave this way. This is all part of the reason I dropped out of the experiment. Not much effort to do things right. It is hard to say what exactly is off, whether it is the preamp or the ADC, a Zoom H1N (essentially voice recorder), or even the turntable. They could have checked to see if it was the Zoom by using another ADC that was available but chose not to for some strange reason. I had also advised them to measure a control cartridge--any cartridge--which could have also helped here and would be useful at the end of the experiment to know if the distortion is related to the cartridge or test record. Luckily we have plenty of wear data already and can be fairly confident about what the results will be, which will help interpret the measurement results here. But without any evidence saying otherwise I would not trust these results to be in any way representative of how the cartridge behaves in a normal set-up. My guess is that the distortion measurements here are artificially low in the high end, so I would suggest one goes by difference from where it is now rather than it meeting a certain percentage to deem it unusable.

Just in case anyone has questions about running the script properly:
ezgif-4-87ac726215.gif
 

JP

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Low end is an electronics problem. Top end may be correct depending on loading.

VM95E_250pF 47k_STR-100.png
 

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Low end is an electronics problem. Top end may be correct depending on loading.

View attachment 300628
That's more like it. With azimuth adjustment that's a nice cartridge. Based on Amir's review of the preamp, my thinking was that its RIAA equalization was exacerbating the results after 1kHz. I mean, a -2.5dB dip at 5kHz, even adjusting for the CBS record dip, seems especially low for an Audio-Technica cartridge. I wonder why distortion on the other measurements are so jumbled up together.
 

JP

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What's the preamp?
 

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What's the preamp?
U-Turn Pluto


U-turn Pluto and ART DJ Pree II phono preamp frequency response measurements.png


This doesn't fully explain the low frequency roll-off unless build quality consistency is extremely poor. (This partly why I was struck by the fact that they didn't want to confirm the results.) I think Amir said RIAA here is good enough, but I am thinking now that even this will color a phono cartridge's output, especially on cartridges like this that already dip a little.
 

JP

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I think they made it pretty clear from the beginning that they didn't care about this part of it.
 

Balle Clorin

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I think the a correct frequency response and how it and distortion changes with wear is quite essential part of the experiment. Please do the FR plot generation correctly


Making photos showing stylus WEAR is extremely challenging and very few can do it well. Frequently plots by recording and using the script is quite easy for most people if they have an interest in doing so, What I mean is that this experiment can show how a FR of a worn stylus looks like and people can recognise it and check their own .
 
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restorer-john

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Making photos showing stylus WEAR is extremely challenging and very few can do it well.

Viewing the styli under a decent optical microscope and seeing the actual wear is not remotely difficult. Photographing it is a different story. You want to see crap stylus photography- go look at the Shure SEK-2 manual. LOL. But that was way back in the late 70s, with 35mm film, no autofocus or good exposure control and no idea what you would get after development/processing. No WYSIWYG digital back then.

I do have another optical microscope in my storeroom, (dual eyepiece not stereoscopic) with a separate camera mount, but I'd need to get a new camera for it and possibly a c-mount adaptor. It's just not worth spending my time, effort and money taking careful photographs for other people on the internet is it?

I do however have a few reticles coming for two of my oculars in order to actually measure the wear patches which I will comment on when testing the various worn styli.
 
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ray_parkhurst

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Viewing the styli under a decent optical microscope and seeing the actual wear is not remotely difficult. Photographing it is a different story. You want to see crap stylus photography- go look at the Shure SEK-2 manual. LOL. But that was way back in the late 70s, with 35mm film, no autofocus or good exposure control and no idea what you would get after development/processing. No WYSIWYG digital back then.

I do have another optical microscope in my storeroom, (dual eyepiece not stereoscopic) with a separate camera mount, but I'd need to get a new camera for it and possibly a c-mount adaptor. It's just not worth spending my time, effort and money taking careful photographs for other people on the internet is it?

I do however have a few reticles coming for two of my oculars in order to actually measure the wear patches which I will comment on when testing the various worn styli.
Your experiment to measure a series of styli with varying amounts of wear and correlate FR/distortion is most welcome. Should give the community some good data to help with replacement decisions. We're hoping our experiment will do a similar thing, though our primary goal is still to determine physical wear vs play time.

A flattened contact patch causes increased distortion, with a "longer" patch (measured in the play direction) causing higher distortion. If you're able to make accurate measurements with your reticles, I'd recommend focusing on this one measurement. I've drawn the Length (L) and Width (W) measurements in on a stylus tip image below. "W" varies quite a bit with different stylus shapes, and determines the total contact area, but "L" is the critical measurement since it tells us how the stylus interacts with the groove in play direction.

LW.jpg
 
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