• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Phonograph Stylus Wear Experiment

ray_parkhurst

Member
Joined
May 18, 2023
Messages
95
Likes
98
Yes - that means it won't PROPERLY track the high frequency... which means increased distortion - it doesn't mean a decrease in primary signal amplitude - the increase in distortion might in fact increase the signal amplitude ... I don't know.

But the assumption that the inability to track FR properly would result in a reduced amplitude at higher frequencies doesn't have much basis I think!
I think many folks can describe the possible mechanisms that would result in the (fundamental) response to decrease with wear. @JP did so above. But I am not sure of the explanation for the response to increase. Many folks seem to believe it could/will happen, so I'm wondering if anyone has a hypothesis? Perhaps we'll at least get some data from this experiment.

At T24 test point, @BMRR will record the STR100, as well as a new VMN95E stylus that we'll keep as a reference. He's also going to do the recordings with a second preamp. This data may help to shed light on the interesting FR seen in the T0 recording.

We're also contemplating eliminating the T48 test point in favor of going straight to T96.
 

JP

Major Contributor
Joined
Jul 4, 2018
Messages
2,250
Likes
2,433
Location
Brookfield, CT
Yes, they seem to. Within this thread and in others I've read and participated in. It may actually be true, but I don't know why.,
I must’ve missed where that was said.
 

BMRR

Member
Joined
Jul 17, 2023
Messages
8
Likes
4
Not much effort to do things right.

I'm doing the best I can under the circumstances, and my efforts have been significant. Please understand:

1) I'm disabled and it takes a bit longer for me to accomplish certain tasks;
2) I currently have about $15 in my checking account and my refrigerator is almost empty, therefore I can't just buy better equipment for the experiment, nor have I received any offers from people willing to loan me better equipment;
3) This experiment is being followed by dozens of people on three different forums (Vinyl Engine, Steve Hoffman, and here); we've received hundreds of suggestions for what we should or should not do, what equipment we should or should not use, etc.; we try to incorporate as many suggestions as we can; if we're unable to incorporate a particular suggestion, there is always a good reason why. That doesn't mean we don't care, or that we're not taking this seriously, or that we aren't trying really hard to do something that will benefit the community.

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.

The only other device I own that is capable of making digital audio recordings is my 12 year old computer. As soon as I learned of the weird frequency response with the first set of recordings, I immediately offered to do another set of recordings using my computer instead of the Zoom. My computer can only record as high as 16 bits and 48 kHz. I was told that is insufficient.

On a related note, I am planning to do another test recording with a different phono preamp, to see if the U-Turn Pluto is the cause of the frequency response problem. I have an ART DJpre II that I can use (it has a much flatter frequency response than the Pluto, according to the ASR review of both of them), and I'm going to ask a friend if I can borrow his U-Turn Pluto 2, which ASR reviewed favorably and received a "Recommended" rating.

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.

I fully support this idea; however, the turntable uses a proprietary headshell and I've been unable to find another one. In order to test a control cartridge, I'd have to dismount the test cartridge, mount the control cartridge, then dismount the control cartridge and remount the test cartridge. I'm very good and very experienced at aligning cartridges, but I can't guarantee that I'd be able to match the original alignment with 100% perfect pinpoint accuracy. It was agreed that this would introduce undesirable variables into the experiment.

We do have a control stylus that we plan to use with the existing VM95 cartridge, which at least allows us to rule out problems with the test stylus. The stylus can be installed and removed without altering the alignment of the cartridge.
 

JP

Major Contributor
Joined
Jul 4, 2018
Messages
2,250
Likes
2,433
Location
Brookfield, CT
2) I currently have about $15 in my checking account and my refrigerator is almost empty, therefore I can't just buy better equipment for the experiment, nor have I received any offers from people willing to loan me better equipment;
3) This experiment is being followed by dozens of people on three different forums (Vinyl Engine, Steve Hoffman, and here); we've received hundreds of suggestions for what we should or should not do, what equipment we should or should not use, etc.; we try to incorporate as many suggestions as we can; if we're unable to incorporate a particular suggestion, there is always a good reason why. That doesn't mean we don't care, or that we're not taking this seriously, or that we aren't trying really hard to do something that will benefit the community.

I must've missed the good reasons why. The responses I got here were along the lines of impatience to get started 'just because' and that feedback may be incorporated in to the next experiment. Actually I think I was requested to design the next experiment. I would've happily lent equipment but with those kind of response to feedback, I didn't sense that this was going to be conducted with proper rigor. Just not up for lending out thousands of dollars of kit to people I don't know who don't want to make the effort on experiment design. We're exposed to a lot of that around here. Sorry.
 

BMRR

Member
Joined
Jul 17, 2023
Messages
8
Likes
4
Just not up for lending out thousands of dollars of kit to people I don't know who don't want to make the effort on experiment design.
That's fine. I wouldn't want to borrow "thousands of dollars of kit" from someone I don't know, or even someone I do know. If, God forbid, something happened to it, I couldn't afford to replace it.

Several months ago we asked if anyone was willing to do the playback portion of the experiment, and I was the only person who volunteered.

I regret that my equipment isn't TOTL, but none of the people who own TOTL equipment raised their hands when we asked for a volunteer.
 

JP

Major Contributor
Joined
Jul 4, 2018
Messages
2,250
Likes
2,433
Location
Brookfield, CT
Don’t really need TOTL for this, but do need a way to validate performance of the electronics, particularly the unknown ADC. Also don’t need expensive stuff - I just dont happen to have any of the less expensive ADCs and wouldn’t buy kit I don’t need just to loan it out.
 

Icewater_7

Member
Joined
May 18, 2023
Messages
23
Likes
4
Location
El Dorado Hills, CA
I've done the imaging of the DUT stylus at T24 (24hr), and as expected can see no wear.


One image I take, but rarely publish, is looking straight down at the tip. This is the same view that is used with the Shure method, but instead of lighting from the side, I use the 45-deg ringlight to illuminate what I call the "contact span", which is the distance across the tip at the lowest point of contact in the groove. I have added this view in projection with the front view.


I have also added a drawing of a typical record groove, with the RIAA max spec (0.25mil radius) for bottom radius. This will give you all an idea of how much space there is between the stylus tip and groove bottom, and as the stylus wears we can all observe the gradual but inevitable groove bottoming.


The stylus will be on its way to @BMRR today for second test point (T48) sequence.

View attachment 301211
Very thorough, great job.
 

Balle Clorin

Major Contributor
Joined
Dec 26, 2017
Messages
1,238
Likes
1,140
Where are the funny frequency responses posted ?

By the way
First I used my computer 3.5mm plug to record .
then to this
and this
and this [ should have gotten the 2 channel but too late now,)
Every step made the recording process more confusing and gave more pitfalls,
Common to all is useless manuals -skipping beginners basics-or no manual at all.
( if you do not have the same sampling rate In windows settings, device settings, in recording software you get strange results… etc)

As long as we look at relative differences the simplest and cheapest may be just fine.
By the way now I have Parks Audio Puffin in my system, and recording through the Toslink out to a Toslink USB converter to PC makes is simple,easy and foolproof to record.
 

BMRR

Member
Joined
Jul 17, 2023
Messages
8
Likes
4
Two more sets of CBS STR 100 Issue 3 test recordings have been done, this time using my friend's U-Turn Pluto 2 phono preamp instead of my original Pluto preamp. Pluto 2 received a good review and a "Recommended" rating here at ASR. It has a flatter frequency response and less aggressive rumble filter than the original Pluto.

In addition to recording the test stylus, I also recorded a second [brand new, never used] VMN95E stylus which we are using as a reference.

Here is the link to the test stylus recordings, which had 24 hours of play time at the time of the recording:


(ZOOM0007.WAV is Side A, and ZOOM0008.WAV is Side B.)

Here is the link to the reference stylus recordings, which had 0 hours of play time at the time of the recording:


(ZOOM0005.WAV is Side A, and ZOOM0006.WAV is Side B.)
 

JP

Major Contributor
Joined
Jul 4, 2018
Messages
2,250
Likes
2,433
Location
Brookfield, CT
That's very different. Switching electronics introduces too many variables - even if the results weren't this different. The time to sort this was before the wear tests began.

BMRR TEST.png
 
Last edited:

ray_parkhurst

Member
Joined
May 18, 2023
Messages
95
Likes
98
We have 5 recordings to compare:

1. T0 on DUT with Pluto 1
2. T24 on DUT with Pluto 1
3. T24 on DUT with Pluto 2
4. T0 on REF with Pluto 1
5. T0 on REF with Pluto 2

I'm most interested in comparing #1 vs #2 (to see if 24 hrs of wear has done anything), #2 vs #3 (to see if there are differences between preamps), and #1 vs #4 (to see if there are any differences between styli).
 

JP

Major Contributor
Joined
Jul 4, 2018
Messages
2,250
Likes
2,433
Location
Brookfield, CT
Seems only 3 and 5 were posted.
 

JP

Major Contributor
Joined
Jul 4, 2018
Messages
2,250
Likes
2,433
Location
Brookfield, CT
@BMRR does music subjectively sound different between the Pluto 1 and 2? I'd think -2dB and -10dB at 100Hz and 50Hz along with nearly +3dB around 11kHz would be rather apparent.
 

BMRR

Member
Joined
Jul 17, 2023
Messages
8
Likes
4
@BMRR does music subjectively sound different between the Pluto 1 and 2? I'd think -2dB and -10dB at 100Hz and 50Hz along with nearly +3dB around 11kHz would be rather apparent.
I haven't had time to listen to actual music with the Pluto 2, and my original Pluto is currently at my friend's house for him to use while I'm using his Pluto 2.
 

BMRR

Member
Joined
Jul 17, 2023
Messages
8
Likes
4
We have 5 recordings to compare:

1. T0 on DUT with Pluto 1
2. T24 on DUT with Pluto 1
3. T24 on DUT with Pluto 2
4. T0 on REF with Pluto 1
5. T0 on REF with Pluto 2

I'm most interested in comparing #1 vs #2 (to see if 24 hrs of wear has done anything), #2 vs #3 (to see if there are differences between preamps), and #1 vs #4 (to see if there are any differences between styli).


DUT stylus, Pluto:

https://drive.google.com/drive/folders/14le9fH-yCUWyEL3C0xBFaEJLriiqXwkH?usp=drive_link

DUT stylus, Pluto 2:

https://drive.google.com/drive/folders/13NfYW6gJZLB7KCCLfm78GZ-7cI1tbYGx?usp=drive_link

Reference stylus, Pluto 2:

https://drive.google.com/drive/folders/189rVW0zzmqMVawje5FSxbzjr6QBoZ7qc?usp=drive_link
 

ray_parkhurst

Member
Joined
May 18, 2023
Messages
95
Likes
98
It looks like we need to reset the process a bit. @BMRR had to give up the original Pluto preamp to get access to the Pluto2, and was not able to complete #2 and #4 from the original recording list. The Pluto2 looks to be giving a flatter response at LF, and eliminates the odd HF response, so we'll use it going forward, but we need to get a comparison between the DUT T24 and REF T0 to be sure we have consistent results and a valid reference. So here is the new list, all linked to in @BMRR's post above:

A. T0 on DUT with Pluto 1
B. T24 on DUT with Pluto 2
C. T0 on REF with Pluto 2

I am now most interested in comparing #B and #C to make sure the two styli are performing about the same, which would give us confidence in the measurement as well as the future usefulness of the REF to compare with the DUT as it wears. I don't think anyone expects any difference between T0 and T24 on the DUT, so as long as that holds true with DUT vs REF, we can continue with the experiment.

Can we get a comparison between #B and #C above?
 
Top Bottom