- Thread Starter
- #181
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.
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.
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.
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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