Introducing the Phono Cartridge Measurement Library

[Jas0_0]

This would be my super quick spiel regarding these measurements. (Again, quick, as I am flattening a lot of things.) I'm going to stick to modern cartridges. I set up my first 10 or so measurements as a sort of primer into what to expect out of stereo cartridges after the 1970s (i.e. what should be considered "good") so you can always turn to that but for this, I'll say the following:

I think that the overall measurements show how little difference there is between cartridges in terms of frequency response, distortion, and crosstalk, at least in terms of what we are measuring, which are new cartridges played on the outer groove, which will only show the best case scenario. You can pretty much split cartridges into those that have a resonance at around 12kHz and those that are flat (and have been traditionally considered the "best cartridges"). Note that you pretty much can't get the latter any more so I wouldn't get worked up about it. The only one I have seen here is the Nagaoka MP500 but I personally don't think it is worth the money.

This being said, there is something not on the measurements that I think is the most important thing of all: the stylus type. It can be thought to determine very important things as the cartridge plays through the record: frequency response consistency, distortion, and the ability to play through record issues. FR drops out as the cartridge progresses, with bigger styli showing bigger differences. Microlinear cartridges will give you the best performance and, frankly, are the ONLY cartridges that I would recommend today. (I have a big post coming about why we need to abandon elliptical cartridges as we were supposed to in the late 1970s with the introduction of cartridges like the Shure M95HE. And how spending more than $100 on one is insane. Hopefully soon.) But here is something else to consider that is something I take more serious now: since there is drop off, is there something beneficial to the Audio-technica house curve, which may suffer a bit at the beginning as it is not as flat, but which may end flatter by the end of the record? Something to consider.

Again, I am simplifying this a lot. But I think these are the things that matter.

TLDR: Your cartridge is an excellent cartridge. Don't worry about it.

Thanks, this is really helpful. I went for the AT33PTG/II as it was the cheapest MC I could find with a boron cantilever and ML stylus. Was worried I might have been falling for marketing speil, so this is reassuring.

 

[EJ3]

How does one gauge cartridge accuracy, what are the terms, and, assuming this is possible, how would we rank them? I just don't understand how we can think that we can do something here that is similar to what those people did with a digital medium. We certainly can make educated guesses by supplementing the information we have gathered with these measurements but we are not providing anything conclusive like in that database. (Like I mention in my previous post, to think about cartridge performance, in addition to these measurements I put a lot of weight on the stylus type.) Please remember as I mention in the first post of this thread that these measurements are of sweeps located on the outer groove. These are best case scenarios and all the results (and variables) change as the cartridge progresses through the record, not to mention as the stylus wears. There really are not any test records that I know of that have sweeps near the outer groove that we can use to get more objective data on performance in that area (perhaps one, but it is not available). More, these measurements are system-wide measurements that include all the variables that affect record playback, not just of the cartridges. The more we get into thinking of such a database the more questions I would have. Could we compare cartridges measured on different tone arms, that use different effective lengths, that are set to different alignments? The last one certainly has an effect on distortion at the beginning and end of the record. Things gets messy fast. This all seems very apples to oranges to me.

What about using a linier tracking turntable to eliminate the inner/outer groove variation?
(I am aware that linier tracking may have other issues but it does minimize this issue).
I personally have one (that happens to have a T4P mount arm).
Mine is a Technics SL-M

Specifications​

Type: fully automatic

Drive method: direct drive

Motor: brushless DC motor

Drive control method: quartz phase locked control

Platter: 325mm, 2.5kg, aluminium die-cast

Pitch control: +-6% range

Speeds: 33 and 45rpm

Wow and flutter: 0.022% WRMS

Rumble: -82dB

Tonearm: dynamically-balanced linear tracking

Effective length: 238mm

Effective mass: 13g (including T4P compliant cartridge)

Cartridge: moving magnet

Dimensions: 526 x 205 x 425mm

Weight: 15kg

 

[Balle Clorin]

Any news FR curves on the way?

 

[USER]

Any news FR curves on the way?

I need to get my act together and finish the ones I have left to do. Around 10 or so cartridges, including a couple that I think are important. (I also need to test that wow and flutter test record that worked out for you.) Hoping to do this at around the 1 year anniversary of this thread, which is coming up very soon. I was simply burned out by the end of the fall.

 

[Jimi Floyd]

Any news FR curves on the way?

Dynavector XX-2 MkII

• Turntable: SME Model 10, arm: SME series V
• Tracking force: 2.00g
• Catridge has currently 325 playing hours on it
• Cartridge is from 2019
• Phono stage: Pro-Ject Phono Box RS2
  • 50 pF / 200Ω on phono stage
  • other graph with 100Ω and a different phono stage (Ayre P-5xe) available
• Cable capacitance: 200pF (arm included)
• ADC: MiniDsp SHD connected with USB to computer (Mac)
• Test record: CA TRS-1007 #2 Side A, tracks 1 & 2. This was the 6th measurement done using this side of this record
• Note: the cartridge top is parallel to the record when playing, nonetheless crosstalk may indicate a small tilt could improve it. Since 2 weeks I am telling myself I should do it....

The cartridge:

Boron cantilever and PF line contact stylus tip:

 

[dlaloum]

Dynavector XX-2 MkII

View attachment 376787

• Turntable: SME Model 10, arm: SME series V
• Tracking force: 2.00g
• Catridge has currently 325 playing hours on it
• Cartridge is from 2019
• Phono stage: Pro-Ject Phono Box RS2
  • 50 pF / 200Ω on phono stage
  • other graph with 100Ω and a different phono stage (Ayre P-5xe) available
• Cable capacitance: 200pF (arm included)
• ADC: MiniDsp SHD connected with USB to computer (Mac)
• Test record: CA TRS-1007 #2 Side A, tracks 1 & 2. This was the 6th measurement done using this side of this record
• Note: the cartridge top is parallel to the record when playing, nonetheless crosstalk may indicate a small tilt could improve it. Since 2 weeks I am telling myself I should do it....

The cartridge:
View attachment 376799

Boron cantilever and PF line contact stylus tip:
View attachment 376800

That's what I would characterise as a "typical" high end MC F/R profile...

Primarily driven by cantilever mass / resonance and rising high end reflect the fact that there is no EQ provided by the loading (which is why you can get an equivalent MM to a flatter F/R)

 

[dagfinn]

1x AT152LP, 3x AT155LC on the same AT150(Mlx) generator. All NOS from Goldring Austraila. 150pF/47k, modified Moon 110LP mkII

 

[mackat]

Signet TK10ML

Edit: updated measurements with new CA-TRS-1007. Still on EPA-A501E (6g) armwand, disregard A501H.

Fozgometer shows normal crosstalk results for both channels using Ultimate Analogue Test LP, around -30 to 35 dB.

Original measurement:

 

[Balle Clorin]

Shure V15 V-MR
Click to increase size
View attachment 297459View attachment 297460
View attachment 297467View attachment 314450View attachment 297468
Notes

• As good as it gets!
  • Essentially flat at ±0.5 dB
    • I would ignore the waviness of the left channel highs and follow the peaks
      • Each test record has its pressing problems
• Lightly used, micro-ridge stylus with beryllium cantilever and dynamic stabilizer brush
• Denon DP-35F has a servo tonearm
  • Compare results at 20Hz with one below to possibly see effect on resonance
• Recorded with Wayne Kirkwood Flat MM Phono Preamplifier (no RIAA for precision) and E1DA Cosmos ADC
• You need to record in 192k for full 3rd harmonic distortion data
• Crosstalk is limited with CA-TRS-1007 but center point at 1kHz should be the measurement (-30 dB)
• I also have copies that show a slight downward slope after 10kHz and I will run a comparison later

Confirmation of results
View attachment 297462View attachment 297463
Notes

• Here I used a Parks Audio Puffin on flat mode with digital out in order to compare and confirm results
  • 44.1 recording limits 2nd and 3rd harmonic distortion data
• Here turntable is Denon DP-30L II (with low mass tonearm)
  • Non-quartz direct drive with much beefier motor and different tonearm
    • So much for turntables having completely different sound signatures!
    • Obviously wow & flutter, rumble, tonearm compatibility, loading, and set-up also matter

CBS STR-100 (Version 3)
View attachment 297465View attachment 297466
View attachment 300630
Stereo Review, December 1984. I would say it is spot on.

Notes

• Biggest difference is a wide 0.5 dB bell dip in the frequency response
  • Account for set-up and general test record margin of error
  • CBS STR-100 test records can vary a little above 10kHz (flattening helps some)
• The sweep oscillator switches at 5kHz very clearly on every CBS STR-100
  • This is how the test record track was made
  • Ignore it and use the midway point
• Crosstalk is limited here to -25dB at 1kHz
• 2nd harmonic distortion is also more limited here at 1kHz to about -40 dB
• Still, this is the best test record still available and at a reasonable price!

I have been aiming for the that linearity from a V15 MR, and with some cheating with Puffin DSP ( AIR +1) I finally got quite close with Shure V15 IV and Jico SAS-B,, on a Denon 51F. It sounds nice, and best of all ,I now know what a linear vinyl response sounds like ....I do not need to buy Unobtainium

Spoiler: AIR

 

[USER]

I have been aiming for the that linearity from a V15 MR, and with some cheating with Puffin DSP ( AIR +1) I finally got quite close with Shure V15 IV and Jico SAS-B,, on a Denon 51F. It sounds nice, and best of all ,I now know what a linear vinyl response sounds like ....I do not need to buy Unobtainium
View attachment 380698

Spoiler: AIR

View attachment 380709

 

[Thomas_A]

I have been aiming for the that linearity from a V15 MR, and with some cheating with Puffin DSP ( AIR +1) I finally got quite close with Shure V15 IV and Jico SAS-B,, on a Denon 51F. It sounds nice, and best of all ,I now know what a linear vinyl response sounds like ....I do not need to buy Unobtainium
View attachment 380698

Spoiler: AIR

View attachment 380709

And 5 kHz distortion below -30 dB. Key to clean sound.

 

[Richard G]

So glad I came across this thread!

The OP wrote
“Storage and abuse is a big factor too and those are the hardest things to gauge when buying second hand, but we can't hold that against the manufacturer. What worries me most now is the diamond cut quality and positioning, which is why I felt forced to get a decent microscope“

Finding this thread has made me realise that in my case it would be very unwise to not get a good microscope
How “good” - good enough to check
- If if how much/ they are worn; and
- more critically: whether using them might be any risk for the vinyl.. Inc 2-3 expensive records, mint, rare, the dearest being ~ USD 600
So obviously a clear view of the styluses. Can they also see clearly if the cantilever is bent (and anything else??)

Almost never having used vinyl since the mid 80s, my knowledge of carts, styluses, is moderate but very patchy.
But in the last five years, I’ve acquired half a dozen turntables, 1970s-80s - varying degrees of audiophile. And all with the carts that they came with … and moving home etc none yet used

Knowledge of microscopes? not far off zero.
I saw a link to the Tomlov DM201 with 1200 x, 7" LCD screen, images 16 MP, 10” stand, with HDMI
But also a reference to not being clear, however I wasn’t sure what could have been more clear(!)
And hence if a slightly dearer ~ Tomlov https://www.amazon.com/TOMLOV-DM202-Max-Microscope-Transmitted/dp/B0B7NKGH1C
with eg
… 25 MP. from photography I’d think 16 MP is plenty. But I’ve never looked at a stylus
… 10” screen (approx double the area). I’d think I’d be much better off connecting it to my PC, with a 32 inch screen
… Magnification of 1500 x (25% more) would be useful?

Or just $10 more gets to 2000 x. and (optical quality at this price??) a dedicated lens for zooming magnifying above 1000 x

Amazon.com

 

[USER]

So glad I came across this thread!

The OP wrote
“Storage and abuse is a big factor too and those are the hardest things to gauge when buying second hand, but we can't hold that against the manufacturer. What worries me most now is the diamond cut quality and positioning, which is why I felt forced to get a decent microscope“

Finding this thread has made me realise that in my case it would be very unwise to not get a good microscope
How “good” - good enough to check
- If if how much/ they are worn; and
- more critically: whether using them might be any risk for the vinyl.. Inc 2-3 expensive records, mint, rare, the dearest being ~ USD 600
So obviously a clear view of the styluses. Can they also see clearly if the cantilever is bent (and anything else??)

Almost never having used vinyl since the mid 80s, my knowledge of carts, styluses, is moderate but very patchy.
But in the last five years, I’ve acquired half a dozen turntables, 1970s-80s - varying degrees of audiophile. And all with the carts that they came with … and moving home etc none yet used

Knowledge of microscopes? not far off zero.
I saw a link to the Tomlov DM201 with 1200 x, 7" LCD screen, images 16 MP, 10” stand, with HDMI
But also a reference to not being clear, however I wasn’t sure what could have been more clear(!)
And hence if a slightly dearer ~ Tomlov https://www.amazon.com/TOMLOV-DM202-Max-Microscope-Transmitted/dp/B0B7NKGH1C
with eg
… 25 MP. from photography I’d think 16 MP is plenty. But I’ve never looked at a stylus
… 10” screen (approx double the area). I’d think I’d be much better off connecting it to my PC, with a 32 inch screen
… Magnification of 1500 x (25% more) would be useful?

Or just $10 more gets to 2000 x. and (optical quality at this price??) a dedicated lens for zooming magnifying above 1000 x

Amazon.com

I write about my own experience with things such as wear and using microscopes in the first couple of posts.

Go through the following carefully:

Introducing the Phono Cartridge Measurement Library

Skip to the index. After years of development we are finally launching our phono cartridge measurement library. These measurements were created using the brilliant cartridge response python script, SJPlot, written by the legendary @scott wurcer and @JP. Information about its origins can be...

audiosciencereview.com

Introducing the Phono Cartridge Measurement Library

Skip to the index. After years of development we are finally launching our phono cartridge measurement library. These measurements were created using the brilliant cartridge response python script, SJPlot, written by the legendary @scott wurcer and @JP. Information about its origins can be...

audiosciencereview.com

Also use the search and look up using microscopes with cartridges. There are several threads that discuss the minimum requirements for usefulness, certainly better than I will here. JP offers some good responses in them.

In addition look at my first 10 or so measurements to see how I use the photographs in conjunction with the results. I structured my initial results as a sort of how to measure and understand measurements guide. Also look at my measurements of worn cartridges (use the index). Personally I think that there are enough issues and odd phenomena consistently found in the measurements that you really do need pictures of the styli to begin to understand them. For instance you can see poorly placed diamonds and uneven wear from poor set-up in some of them.

The wear and damage question is something else altogether. We don't have definitive answers but I also offer my best guesses as to the effect and how to "see" it in the measurements.

The second post that I linked has my set-up if you want to see what I used. Note that, as I mention, the images I post with my measurements are barely useful. This means you don't want anything that is a step down. But it is tricky to gauge the quality of USB-microscopes as their resolution and capabilities are greatly exaggerated by ad copy. Take the time to learn to read through the bullcrap. That's the best advice I can give. But the specs of the one I posted should be the minimum you should seek should you go with that kind of microscope. If you do get something similar the next step is to practice your lighting technique as I find that to be a major factor in the results. Don't expect to produce good results right away. It will take some time. There are other more traditional and higher quality approaches such using real microscopes, but that is an even more expensive route and I have no advice on that.

Finally, some questions. Why exactly are you considering a microscope? Do you buy a lot of used cartridges? Are you planning on measuring a lot of cartridges? Are you looking to gauge the wear of a single cartridge that you are using? If the last one, can't you simply make an educated guess as to how long it has been used? Make sure this investment of time and money is worth it because it is not a modest investment.


Addendum: with the microscope I use I place the stylus at a 45 degree angle from the lens in order to take the wear photographs. Blutak is helpful to hold the cartridge. (I place it on a small z-axis pedestal for fine adjustment.) I use the two gooseneck lamps from a sloping angle and supplement it with another light source from the back. (The hardest thing is learning when the gooseneck lights are lighting the right part of the stylus tip correctly.) But before adjusting the lights I wrap everything with tissue paper (between the lights and the cartridge) to diffuse the light while also providing as much even light as possible. This makes a huge difference in sharpness.

 

[JP]

Lots of good info in this thread: https://audiokarma.org/forums/index.php?threads/sparkys-fabulous-diy-stylus-microscope.225960/

 

[tpd]

The link from JP and info from USER above is a good place to start. I am not an expert on this subject, but can share my experience putting together an affordable microscope for evaluating used styluses.

It doesn't have to be expensive if you're willing to be patient and shop around. There are LOTS of very capable lab microscopes in the world that are capable of doing what you want to do. My own setup is a surplus AO Spencer Sixty. I use 4x and 10x objectives and have a variety of eyepieces giving a useful range of magnification options.

Lighting is from a pair of magnet-base LED grill lights. I also purchased a $50 USB camera that slips into the eyepiece. It works reasonably well out of the box.

There's a bit of experimenting still to do to optimize this setup. The optics could be cleaned and the Sixty is a bit limited with regard to available eyepieces and objectives. If I used it more often I might put more effort into upgrading to a better microscope. Including the USB camera and accessory eyepeices I have less than $100 in my current setup.

Example of what I can capture here. This is barely adequate for evaluating wear. I find that the actual viewed image is better than what I can capture, though.

 

[aaaakkkk]

The link from JP and info from USER above is a good place to start. I am not an expert on this subject, but can share my experience putting together an affordable microscope for evaluating used styluses.

It doesn't have to be expensive if you're willing to be patient and shop around. There are LOTS of very capable lab microscopes in the world that are capable of doing what you want to do. My own setup is a surplus AO Spencer Sixty. I use 4x and 10x objectives and have a variety of eyepieces giving a useful range of magnification options.

Lighting is from a pair of magnet-base LED grill lights. I also purchased a $50 USB camera that slips into the eyepiece. It works reasonably well out of the box.

There's a bit of experimenting still to do to optimize this setup. The optics could be cleaned and the Sixty is a bit limited with regard to available eyepieces and objectives. If I used it more often I might put more effort into upgrading to a better microscope. Including the USB camera and accessory eyepeices I have less than $100 in my current setup.

Example of what I can capture here. This is barely adequate for evaluating wear. I find that the actual viewed image is better than what I can capture, though.

View attachment 381896

You can significantly improve the quality of your pictures by replacing the USB camera with a photo camera, for example, this Samsung NX1000, you can also choose a higher aperture lens 10x40 or 20x40

 

[JP]

Signet TK100 LC

This one paid a brief visit yesterday. IIRC, <50 hours on it.

 

[JP]

Audio Technica AT25 VM

Another interloper for a few hours. This was NOS.

 

[USER]

Audio Technica AT25 VM

Another interloper for a few hours. This was NOS.

View attachment 382424

Stereo Review, Oct. 1979.

 

[dlaloum]

Signet TK100 LC

This one paid a brief visit yesterday. IIRC, <50 hours on it.

View attachment 382422

Looks like a good candidate for custom load EQ... although capacitance loading on these is tricky as they are low inductance.... (requires high capacitances as a result to EQ)