Introducing the Phono Cartridge Measurement Library

[melloncolliecat]

Very interesting! @dagfinn So, does the ATN155LC/TKN7LCa have lower tip mass or is there something else at play there?

 

[morillon]

First @USER, I hope it's ok to post some measurements not following the formula. They are based on 30kHz pink noise, so a little different. They were made for this project, as mentioned.

Dividing MM Carts into electrical parts with individual Transfer Functions

In a joined effort, Bill, Dagfinn and I went into much detail by developing replacement diagrams for MM cartridges, divided into two parts, first the output section with coil, that we called the Generator, and second for the complete Cantilever assembly. An achievement never realized before to...

www.diyaudio.com

What I have is FFT's of 30 seconds pink noise snippets, corrected for 3dB/octave slope. These are done using a Denon DP-57L turntable, a Simaudio Moon 110 mkII phonostage, modified by Hans Polak to perfect flatness. Samples were recorded using a Motu M4. The Denon tonearm/interconnect measures to 98,5pF, (rounded to 100pF), and the Moon was set to 50pF/47kOhm. Resolution was 24/196.

So, what is not covered in the paper are some later samples I did using different inserts on the AT150Mlx generator, since I have a few different styli fitting the AT150. So differences we see is due to the cantilever and stylus assembly only. I have no conclusions or final analysis, I just started looking at the data.

This is the AT150MLx in original configuration, with goldplated boron cantilever and MicroLine stylus, fairly new, sub 50 hours. I think we recognize the profile from the many measurements already published here, except it's extended (as the source is the CH Precision setup disk. Note: it's a 7"/45", so sampled disk radius is about 8 cm ).
View attachment 374295

As comparison, this is the same AT150 with a beryllium/shibata insert, an unused Signet TKN7LCa. Quite a difference! I have a few more cantilevers, but this illustrates what's there. (If this is the wrong thread, maybe there's a different thread to post more, if there is interest?)
View attachment 374301

A beryllium/shibata pic, ATN155LC, virtually the same as TKN7LCa.
View attachment 374303

155lc...line contact not shibata ;-)
existed after in golden beryllium..160ml
(ps 150 360mH..old 155 490mH)

 

[Balle Clorin]

@dagfinn ,
What is the E1 thing in LTSpice, I want to make and run the Ltspice sim myself..

found it

 

[sofrep811]

What Are you talking about?

No idea. Whatchoo you talking about, Willis?

 

[DSJR]

Shure V15 Type III MR

View attachment 372529

• Turntable: Thorens TD124, arm: SME 3009 series 2 improved (fixed headshell)
• Tracking force: 1.05g
• Stylus VN35MR has currently 128 playing hours on it
• Cartridge is from 1976, stylus is from 2000
• Phono stage: Pro-Ject Phono Box RS2
  • 100 pF / 47kΩ on phono stage, thus 250pF total capacitance, including cables
  • other graphs with 200pF, 300pF, 350pF total capacitance available
• Cable capacitance: 150pF (arm included)
  • Measured by user Barry at The Art of Sound
• ADC: MiniDsp SHD connected with USB to computer (Mac)
• Test record: CA TRS-1007 #2 Side B, tracks 1 & 2. This was the 2nd measurement using this side of this record
• Note: the blue crosstalk dip at 6-9 kHz is not there in a measurement I did using side A of the same record

The cartridge:
View attachment 372531

Azimuth setting method, using an L-shaped piece of paper.....
View attachment 372532

This is the first measurement I am posting in this thread. Please be kind. My deepest thanks go to the script author Scott Wurcer, to @JP and @USER for starting the two threads which taught me how to use it making my dream of measuring my cartridges' frequency response come true.

Darn - You know, I don't think we ever saw the official MR stylus for this model

 

[Jimi Floyd]

Darn - You know, I don't think we ever saw the official MR stylus for this model

Actually I have 3 more:

Unfortunately the two on the left (the "reds") are not in perfect shape anymore. I never used them, just tested. The diamond is new, but the (rubber?) suspension somehow softened or "gave way" and they now would ride very low. This is the correct height for a V15, the "black stylus I measured for this thread:

And this is the best of the two "reds", with the other the cartridge screws would almost touch the record:

Anybody here knows if it is possible to restore the rubber suspension or anyway recover those styli?

 

[dlaloum]

Anybody here knows if it is possible to restore the rubber suspension or anyway recover those styli?

I have heard of retippers replacing the suspension...

You would need to talk to a few retippers

 

[dagfinn]

It looks like C is a bit higher than 150pF. What’s the measured input C of the Moon?

According to Hans Polak who modified it, 50pF is correct, including traces and plugs. 98,5 is measured using a DER DE-5000.

 

[dagfinn]

Did you at any stage try deducting the calculated electrical response from the measured response, to extract the raw cantilever/needle behaviour?

LD had provided the calculations and spreadsheet to do this - but it assumed basic LCR and didn't include additional lower level non linearities (such as eddy currents)

The model I have (those spreadsheets) was therefore imperfect... but did achieve a decent level of predictability.

It also highlighted that the (a) major differentiator in FR was the cantilever and its resonance...

I'm afraid Hans would have to answer that, I'm just the aid.

 

[dagfinn]

Very interesting! @dagfinn So, does the ATN155LC/TKN7LCa have lower tip mass or is there something else at play there?

Beryllium is slightly lighter, but may also behave differently as far as resonances goes? We see that in speaker drivers, but I'm speculating. I have some more inserts to look at, both 155 and 152. These are 40 years old NOS, so old suspensions vs the 150MLx, which is fairly new. But I also have VMN40ML and ATN140ML, which should be quite similar, except for age.

 

[DSJR]

Actually I have 3 more:

View attachment 374430

Unfortunately the two on the left (the "reds") are not in perfect shape anymore. I never used them, just tested. The diamond is new, but the (rubber?) suspension somehow softened or "gave way" and they now would ride very low. This is the correct height for a V15, the "black stylus I measured for this thread:

View attachment 374434

And this is the best of the two "reds", with the other the cartridge screws would almost touch the record:

View attachment 374435

Anybody here knows if it is possible to restore the rubber suspension or anyway recover those styli?

Rub it in, why don't you!

Original NV35E's often rode low at 1g downforce, leaving fixing bolts close to the record. The bottom pic looks just fine, the diamond set slightly back on the cantilever I think.

The slight perceived hardness of tone in the original elliptical seemed somehow tamed a touch in the SME headshell by using the tacky black goo they made available between cartridge and shell. Got to say I never really got on with the low mass plastic screws they supplied, but using 2.5mm Allen bolts and nuts added too much mass and the standard 'fixed shell' counterweight now slung out almost as far as it'll go, was/is best replaced with the S2 detachable-shell counterweight as I'll need to do for mine, which is set up with V15III ready to go one day...

 

[dagfinn]

@dagfinn ,
What is the E1 thing in LTSpice, I want to make and run the Ltspice sim myself..
View attachment 374389

I'm afraid this is Hans or Bill's department, sorry. If you contact Hans on DIYaudio, I'm sure he'll provide anything you want, and will explain in detail. Wish I was en EE.

 

[dagfinn]

155lc...line contact not shibata ;-)
existed after in golden beryllium..160ml
(ps 150 360mH..old 155 490mH)

You're right, they used LC. But, we can look at the cut and it's shape? Sometimes they use word to be different, like you see with the microline. Shure called it MicroRidge, but it's still Namiki patent. AT sometimes called it modified shibata, which could reference the radius, large or small (75/50?). Anyway, here's the AT20Sla, which was called shibata. Looks similar?

 

[dlaloum]

Berillyum is slightly lighter, but may also behave differently as far as resonances goes? We see that in speaker drivers, but I'm speculating. I have some more inserts to look at, both 155 and 152. These are 40 years old NOS, so old suspensions vs the 150MLx, which is fairly new. But I also have VMN40ML and ATN140ML, which should be quite similar, except for age.

The resonance can be measured, the tip mass is calculated - but it is calculated from the resonance (!).... so the two actually are the same thing simply expressed differently.

If the Berillium cantilever version is lighter, then the resonance will perforce be higher...

I posted (and discussed extensively) about it on VE back in 2012...

Calculating / Measuring Effective stylus mass- Vinyl Engine

www.vinylengine.com

The outcome of which was the following formula:

ETM =((1/(ResF*2*3.14159)^2)/[1.16 x 10^(-10)])

For details, refer to the VE thread... - this form of the formula is based on some assumptions about a couple of values... but has been tested against a number of styli with known ETM specs.

 

[dagfinn]

The resonance can be measured, the tip mass is calculated - but it is calculated from the resonance (!).... so the two actually are the same thing simply expressed differently.

If the Berillium cantilever version is lighter, then the resonance will perforce be higher...

I posted (and discussed extensively) about it on VE back in 2012...

Calculating / Measuring Effective stylus mass- Vinyl Engine

www.vinylengine.com

The outcome of which was the following formula:

ETM =((1/(ResF*2*3.14159)^2)/[1.16 x 10^(-10)])

For details, refer to the VE thread... - this form of the formula is based on some assumptions about a couple of values... but has been tested against a number of styli with known ETM specs.

Yes, mass and res can be calculated and Be will be higher. I really have to work at maths, so I let others do it .
I have more Be styli, so we'll see how it all works out empirically. It's tempting to draw early conclusions.

Like I did with this one, Signet TKN9LCa on a TK10 generator (NOS, sub 20 hours). Tapered beryllium with lc/shibata. I expected perfection, but alas...

Not what I expected, I can't explain this.

 

[morillon]

You're right, they used LC. But, we can look at the cut and it's shape? Sometimes they use word to be different, like you see with the microline. Shure called it MicroRidge, but it's still Namiki patent. AT sometimes called it modified shibata, which could reference the radius, large or small (75/50?). Anyway, here's the AT20Sla, which was called shibata. Looks similar?
View attachment 374502

sorry..I'm not expert enough and only stupidly pointed out what is written on the box...
personally, even if we saw the return of all types of diam on the market..
I was a little confused remained on the idea of shibata-period quadraphony..
(personally against the grain I moved away from vinyl, and in my downgrade, am precisely going to this body of 155-160 on diam lc (or certain ml but not shibata).. . even if I have "heavier" things in the drawers...)
;-)

 

[dlaloum]

Yes, mass and res can be calculated and Be will be higher. I really have to work at maths, so I let others do it .
I have more Be styli, so we'll see how it all works out empirically. It's tempting to draw early conclusions.

Like I did with this one, Signet TKN9LCa on a TK10 generator (NOS, sub 20 hours). Tapered beryllium with lc/shibata. I expected perfection, but alas...
View attachment 374503
View attachment 374504
Not what I expected, I can't explain this.

Just because it's an exotic cantilever, doesn't mean it is low mass...

I have one of the lower end eliptical versions of the same cartridge /stylus - and had similar results

 

[dlaloum]

sorry..I'm not expert enough and only stupidly pointed out what is written on the box...
personally, even if we saw the return of all types of diam on the market..
I was a little confused remained on the idea of shibata-period quadraphony..
(personally against the grain I moved away from vinyl, and in my downgrade, am precisely going to this body of 155-160 on diam lc (or certain ml but not shibata).. . even if I have "heavier" things in the drawers...)
;-)

Vinyl quadrophony had a carrier wave up around 30 or 40kHz, and required an edge width (horizontal) sufficiently narrow to be able to reproduce the required carrier (not without distortion... but sufficiently to lock it in) - that narrow edge, meant that in eliptical form, it would have substantial wear issues - hence the development of the line contact shibata to spread the load, and make it all work.

There were a few other profile shapes in the early days, Stanton had their own (can't recall the name at the moment), B&O had the prahmanik...

There's a few old threads on VE discussing the various shapes.

 

[Thomas_A]

I

Yes, mass and res can be calculated and Be will be higher. I really have to work at maths, so I let others do it .
I have more Be styli, so we'll see how it all works out empirically. It's tempting to draw early conclusions.

Like I did with this one, Signet TKN9LCa on a TK10 generator (NOS, sub 20 hours). Tapered beryllium with lc/shibata. I expected perfection, but alas...
View attachment 374503
View attachment 374504
Not what I expected, I can't explain this.

Stylii are like jewels, some are more perfect than others. Regarding old stylii there is also the suspension issue. Rubber age.

 

[morillon]

Yes, mass and res can be calculated and Be will be higher. I really have to work at maths, so I let others do it .
I have more Be styli, so we'll see how it all works out empirically. It's tempting to draw early conclusions.

Like I did with this one, Signet TKN9LCa on a TK10 generator (NOS, sub 20 hours). Tapered beryllium with lc/shibata. I expected perfection, but alas...
View attachment 374503
View attachment 374504
Not what I expected, I can't explain this.

the measurement in my more modest case is just useful for adjustments, very often relative constraints, and not very fundamental research like here... ;-)))
I have not kept these measurements but precisely on 155 lc of origin almost new, rubber ok...
I had an answer on low capacitance that was much less specific , no big peak... easy to manage.... I appreciate it for that compared to other solutions at ml that I have or I had etc....
;-)