Phonograph Stylus Wear Experiment

[ray_parkhurst]

This discussion does bring up good points regarding both measurement capabilities, human hearing, and what we should actually be looking for in this study. My hypothesis is that distortion measured at 15kHz will be more sensitive in discriminating stylus wear vs lower frequencies, especially for inner grooves. I do question whether those measured distortion numbers are correct in absolute level, so saying that most cartridges have >10% distortion is open to debate, but I also think if the distortion rises by a certain amount, that is probably fairly accurate by comparison as long as the same system is used for making the measurements and analysis. Does anyone disagree with my statements/hypothesis above?

 

[morillon]

I don't see why we are talking about hearing...
this is for measurement...
and yes .. to observe the evolution of the thd over the hours .. not a story of absolute value
..
but you need a nice rigor in the protocol...
and never having to observe by comparison between two same measurement discs what comes from the wear of the disc...
but I maintain that if at low velocities and on a few measures should pass..

but when do you subjectively judge that it is worn out and under what conditions...?

 

[Thomas_A]

This discussion does bring up good points regarding both measurement capabilities, human hearing, and what we should actually be looking for in this study. My hypothesis is that distortion measured at 15kHz will be more sensitive in discriminating stylus wear vs lower frequencies, especially for inner grooves. I do question whether those measured distortion numbers are correct in absolute level, so saying that most cartridges have >10% distortion is open to debate, but I also think if the distortion rises by a certain amount, that is probably fairly accurate by comparison as long as the same system is used for making the measurements and analysis. Does anyone disagree with my statements/hypothesis above?

Comparing distortion curves using the same system would work. But at best you will have 5-10%THD between 10-20 kHz using the best (and new) test records.

 

[ray_parkhurst]

I don't see why we are talking about hearing...
this is for measurement...
and yes .. to observe the evolution of the thd over the hours .. not a story of absolute value
..
but you need a nice rigor in the protocol...
and never having to observe by comparison between two same measurement discs what comes from the wear of the disc...
but I maintain that if at low velocities and on a few measures should pass..

but when do you subjectively judge that it is worn out and under what conditions...?

Hearing is an important element in audio. Let's say that we measure Harmonics at 5kHz, 10kHz, and 15kHz, and find severe degradation at 15kHz, minor degradation at 10kHz, and almost no change at 5kHz. Does that mean the test has shown the cartridge to be unusable? I'd say not, since the Harmonics at 10kHz and 15kHz can't be heard by humans. If we disregard the range of human hearing, we might make a mistake in our judgment on acceptable wear and correlated performance. That said, I want to know how much degradation occurs at 15kHz whether it's audible or not since it gives visibility into the condition of the stylus.

 

[ray_parkhurst]

Comparing distortion curves using the same system would work. But at best you will have 5-10%THD between 10-20 kHz using the best (and new) test records.

I'm good with that, as long as the distortion readings are consistent and represent actual harmonics from the stylus, not something coming from other aspects of the system. I'm not sure how to determine that, but hopefully the totality of the data taken can be used to determine its validity.

 

[sq225917]

Why not use a dj record with a locked groove as the wear medium?

Then just play another record at 100 hour intervals to record the test samples.

 

[morillon]

Hearing is an important element in audio. Let's say that we measure Harmonics at 5kHz, 10kHz, and 15kHz, and find severe degradation at 15kHz, minor degradation at 10kHz, and almost no change at 5kHz. Does that mean the test has shown the cartridge to be unusable? I'd say not, since the Harmonics at 10kHz and 15kHz can't be heard by humans. If we disregard the range of human hearing, we might make a mistake in our judgment on acceptable wear and correlated performance. That said, I want to know how much degradation occurs at 15kHz whether it's audible or not since it gives visibility into the condition of the stylus.

that's why I insist on:

""but when do you subjectively judge that it is worn out and under what conditions...?""

and after hoping for a magnifying effect at this frequency...
the concern is not the measured observations but the subjective estimation..

 

[Balle Clorin]

Why not use a dj record with a locked groove as the wear medium?

Then just play another record at 100 hour intervals to record the test samples.

I think the groove must be modulated, not a silent groove as on my records with a locked infinite groove.

 

[morillon]

ps could be interesting to investigate the shure tri-tone (ttr-117) for this use ..
as observation mix measurement imd- subjective listening at low level

as a test originally made to be listened to for tracking but also with its structure with a 17k..
price be solution....

I don't have it.. but it is very common...

ps observing the classic tracking tests and observing the degradation of this one is somewhere a fairly basic solution for observing wear
;-)
but what is the acceptable threshold of wear and tear for each other in their uses?

 

[BendBound]

Why not use a dj record with a locked groove as the wear medium?

Then just play another record at 100 hour intervals to record the test samples.

Sorry to be so delayed in getting back to this thread. A friend of mine passed last week and I have been dealing with that with the family.

Ray Parkhurst run an experiment where he essentially played one record for 1,000 plus hours. One critique offered was that such play was not reasonable or indicative of how we all play records. Research exists from the mid- to late-1960s (don't hold me to that period) that shows repeated play of one record has measurably different impact on stylus wear compared to using a multitude of records. We don't want this endeavor to fall into that trap. So we have designed an experiment with many records of mostly VG++ and better condition records, cleaned very well, to run each side for effectively 12 hours.

We can point to 12 hours of continuous play as an issue, but we trust its minor or even a non-issue relative to the VTF-hour based use of a elliptical stylus. As further control, we are monitoring humidity and temperature under the turntable cover so to speak to ensure the system is not overheated by 24-hour per day play. If the system does heat up we can mitigate that with an undercarriage small fan.

 

[BendBound]

Comparing distortion curves using the same system would work. But at best you will have 5-10%THD between 10-20 kHz using the best (and new) test records.

Ray has already dealt with this to some degree.

I've recorded three sides of vinyl already, in effect, prior to the experiment run. Two of the three sides are on two copies of the same title, the same side. These recording were done on following kit:

Ortofon Cadenza Black, retipped with a Paratrace stylus by Expert Stylus & Cartridge out of the UK. I have about 200 hours on that stylus tip, which according to proprietor Mr. Wyndham Hodgson is a highest grade vector property aligned diamond tip, advanced shape.

The tonearm used is The Woody made by Pete Riggle in Richland, Washington. The unipivot arm is nine (9") inches long. I employ his VTAF device to get SRA at ~92°. The VTF is 2.3g. I use a Baerwald alignment dialed in by DB protractor. Anti-skate and azimuth are carefully aligned. A first surface mirror is used for azimuth and also check by recording prior several tracks of a mono record to evaluate channel balance in IzotopeRX9 software. See this review from a handful of years ago: Mike Bodell's Review of Pete Riggle's String Theory™ Woody™ Tone Arm. The tonearm is wired with Discovery Plus IV wiring harness.

The turntable is a modified JA Michell Gyro SE. The suspension has been modified by replacing the spring system with a pylon o-ring castle nut suspension. Under the stock armplate I've incorporated an acrylic ring system to raise the arm and control vibration, similar to that sold by Gert Pedersen of Denmark. The turntable uses the Never Connected PSU and upgraded DC motor, placed three shelves down in a stereo rack made by Mapleshade.

The entire kits sits on vibration control discs, on a large Samson maple block (Mapleshade), on more vibration control devices that employ ball bearings, and other vibration control elements, and that sits on a thick maple shelf unit.

This system is connected to a Whest PS.40RDT SE phono preamp. This link will take anyone interested to technical details in a write up on the phono preamp.

RCA cables made by Audio Envy connect the phono preamp to a Tascam DA-3000 pro recorder. This link takes you to technical details on the recorder. I use the factory recommended input gain. I record at 96kHz and 24 bit.

 

[morillon]

the bias of the settings approach to antiskating is really a delicate subject, debatable and significantly impacting the subject of wear...
ouch

 

[USER]

The tonearm used is The Woody made by Pete Riggle in Richland, Washington. The unipivot arm is nine (9") inches long. I employ his VTAF device to get SRA at ~92°. The VTF is 2.3g. I use a Baerwald alignment dialed in by DB protractor. Antiskate and azimuth are carefully aligned. A first surface mirror is used for azimuth and also check by recording prior several tracks of a mono record to evaluate channel balance in IzotopeRX9 software. See this review from a handful of years ago: Mike Bodell's Review of Pete Riggle's String Theory™ Woody™ Tone Arm. The tonearm is wired with Discovery Plus IV wiring harness.

The turntable is a modified JA Michell Gyro SE. The suspension has been modified by replacing the spring system with a pylon o-ring castle nut suspension. Under the stock armplate I've incorporated an acrylic ring system to raise the arm and control vibration, similar to that sold by Gert Pedersen of Denmark. The turntable uses the Never Connected PSU and ungraded DC motor, placed three shelves down in a stereo rack made by Mapleshade.

The entire kits sits on vibration control discs, on a large Samson maple block (Mapleshade), on more vibration control devices that employ ball bearings, and other vibration control elements, and that sits on a thick maple shelf unit.

Wouldn't it be better to use a less esoteric set-up and instead something robust, proven, and popular like a Technics SL-1200 MKII? No offense, but I'd personally trust the results more that way. Technics are known inside and out and are closer to instrument grade than audiophile turntables (not that there is anything wrong with using them to paraphrase Seinfeld).

 

[ray_parkhurst]

Quite a critical audience here! As a reminder, the audiophile setup describe by @BendBound is not the system used for the wear experiment, just the system used to capture the playback of a select group of records before and after they are played by the new and worn stylus used in the experiment. The same system is used in both cases, so it should be quite capable of detecting damage done to the record due to the long play hours, or due to the worn stylus, or both.

 

[morillon]

there is a possible approach that will greatly limit the variables due to biases of arm length, antiskating and impacts on wear....
it is the tangential arm that will make the most sense for make the wear.....

and the observation (the optical -thd correlation thd 10 or 15k?) is of interest only if we try to correlate with a subjective estimate...
and that s the difficulty...

 

[USER]

Quite a critical audience here!

Only trying to help. And it's not like I'm suggesting anything crazy, it's just that my internal alarm always goes off when I hear or read the word modification. This medium is so finicky and has so many variables that can go wrong it's never a bad thing to simplify.

 

[BendBound]

there is a possible approach that will greatly limit the variables due to biases of arm length, antiskating and impacts on wear....
it is the tangential arm that will make the most sense for make the wear.....

and the observation (the optical -thd correlation thd 10 or 15k?) is of interest only if we try to correlate with a subjective estimate...
and that s the difficulty...

Thank you for that suggestion. When I put this thread together, I did not want to reproduce all that has been posted on Vinyl Engine or the Steve Hoffman Forum. But after I prepared an article published in the Vinyl Press on my sojourn to understand how long a stylus tip lasted, a piece that used images by Ray Parkhurst, Ray and I talked about a how to create a contemporary styli wear experiment that employed sufficient common variables to have the greatest chance to inform those looking for an answer to the same question on wear hours. That discussion is laid bare actually in a SHF thread about the Finish Line article, started actually by Bill Hart, who is The Vinyl Press. We just discussed what would be a protocol for such a test.

Shortly thereafter, Ray took it upon himself to run such an experiment as recorded on the Vinyl Engine, as seen here Stylus Wear Study. In this July 2019 onward experiment, he used a linear tracking turntable to do precisely as you suggest, minimize the impact of all the set up variables to stylus wear. Besides noting the very low VTF employed in that experiment, critics to the experiment focused on the use of a linear tracking turntable. I used to own several, B&O TX-2s, now sold, but honestly, folks looking for a reason to preserve their belief on very long hours of stylus use to critical wear found these features of Ray's experiment to be flawed.

I note this not as a critique of the fine suggestions forwarded here, because they absolutely have caused us to stop and think about our procedure. But I cannot over emphasize our stated goal of replicating what most folks do in playing records. This goal to us is the 80/20 rule, a focus on a procedure most folks will say is indicative of how they play records, in the shape we list, and at a VTF they use (more or less) and on turntables most of us use. To be honest, that turntable is not a linear tracker.

 

[BendBound]

Only trying to help. And it's not like I'm suggesting anything crazy, it's just that my internal alarm always goes off when I hear or read the word modification. This medium is so finicky and has so many variables that can go wrong it's never a bad thing to simplify.

I get that and thank you much for helping us think this out. With regards to modification of the JA Michell Gyro SE, its spring suspension has been updated even by Michell Engineering. That original suspension introduced noise to the chassis and platter, both of which smeared the signal from the tonearm and cartridge. The serial number for my Gyro is 049, manufactured on 24 March 1999. Several folks have worked to upgrade that element of the turntable. The use of Pete Riggle's VTF is just to ensure the cartridge is set up properly and to minimize travel up or down for the tonearm, an acrylic spacer is employed under the arm plate. Some folks simply used spacers, but I wanted a more flexible set up. The "tweeks" or mods are simply designed to optimize performance.

From that perspective, I can see how someone would argue we are not using the famous direct drive Technics SL-1200. But as Ray noted, the kit I used was simply to capture 96/24 dubs on three essentially NM- records to potentially hear sonic changes later after those have been used in the experiment, and even to visually see groove wear that Ray will examine also.

 

[JP]

Can I assume the cartridge used for those laybacks will not be used in the interim?

 

[morillon]

I get that and thank you much for helping us think this out. With regards to modification of the JA Michell Gyro SE, its spring suspension has been updated even by Michell Engineering. That original suspension introduced noise to the chassis and platter, both of which smeared the signal from the tonearm and cartridge. The serial number for my Gyro is 049, manufactured on 24 March 1999. Several folks have worked to upgrade that element of the turntable. The use of Pete Riggle's VTF is just to ensure the cartridge is set up properly and to minimize travel up or down for the tonearm, an acrylic spacer is employed under the arm plate. Some folks simply used spacers, but I wanted a more flexible set up. The "tweeks" or mods are simply designed to optimize performance.

From that perspective, I can see how someone would argue that by not using the famous direct drive Technics SL-1200. But as Ray noted, the kit I used was simply to capture 96/24 dubs on three essentially NM- records to potentially hear sonic changes later after those have been used in the experiment, and even to visually see groove wear that Ray will examine also.

I well imagined the idea was to be rather in classic conditions and general public..
(but the subject of antiskating remains a delicate thing, hence the essence of my reaction...)

you just came to present your experience.....
OK
but
I maintain 3 small things....
- the importance of a rather linear observation in terms of the frequency of measurements taken...
not :
"""
This analytical process will be conducted at 0hrs (i.e., the new stylus), 48hrs, 96hrs, 240hrs, 360hrs, and 480hrs, with timing adjusted based on observations. A further test point after 480hrs would be added if necessary
""

- more anecdotal because very simple to make
if a thd observation on high frequencies..
(and be careful if observing high frequency to use signals that are not too strongly modulated so as not to accelerate the wear of the test disc
)
to do the obligation to measure at more than 96k...
no harmonics.. no thd
;-))
(and to ensure that the phono preamp has a large useful bandwidth)
see can observe if a classic imd test helps factual observation in thd...

- and that all this only makes sense if a reflection on the correlation has a subjective approach to annoying wear or not...

I stop it...
;-)


have fun.....
;-)