Introducing the Phono Cartridge Measurement Library

[dlaloum]

According to old 'Choice tests, the Ortofon OM body has a resonance in the mid to upper hundred Hertz region which shows on response plots and separation tests done back then.

The super OM and OM differ in their inductance - hence the natural resonance of the LCR circuit formed by the body and the phono stage loading, will move... all high inductance designs have it - and the resonant frequency can be calculated - you can use that to boost certain frequencies or critically damp it...

Given the same load and the same needle - the impact of the LCR / cartridge inductance will be the primary difference.

Which is better, OM or SuperOM, actually depends on the needle fitted and the tuning of the load.... they are otherwise the same design. Which is to say, the Ortofon SuperOM has the same electrical resonance, as do all cartridges! - there is no substantive physical "body" resonance difference between the bodies.

 

[Thomas_A]

The super OM and OM differ in their inductance - hence the natural resonance of the LCR circuit formed by the body and the phono stage loading, will move... all high inductance designs have it - and the resonant frequency can be calculated - you can use that to boost certain frequencies or critically damp it...

Given the same load and the same needle - the impact of the LCR / cartridge inductance will be the primary difference.

Which is better, OM or SuperOM, actually depends on the needle fitted and the tuning of the load.... they are otherwise the same design. Which is to say, the Ortofon SuperOM has the same electrical resonance, as do all cartridges! - there is no substantive physical "body" resonance difference between the bodies.

I think @DSJR refers to a mechanical resonance of the cartridge body at ≈420 Hz. A small dip can be seen in my previous measurements too.

 

[killdozzer]

This is just too good for words.

 

[DSJR]

The super OM and OM differ in their inductance - hence the natural resonance of the LCR circuit formed by the body and the phono stage loading, will move... all high inductance designs have it - and the resonant frequency can be calculated - you can use that to boost certain frequencies or critically damp it...

Given the same load and the same needle - the impact of the LCR / cartridge inductance will be the primary difference.

Which is better, OM or SuperOM, actually depends on the needle fitted and the tuning of the load.... they are otherwise the same design. Which is to say, the Ortofon SuperOM has the same electrical resonance, as do all cartridges! - there is no substantive physical "body" resonance difference between the bodies.

I'm talking a physical resonance in the BODY DESIGN, not electrical characteristics here and in the plots done back then, all half inch mount OM models seemed to exhibit it - a response glitch plus separation notch at similar frequencies. The 'Super' body I believe has slit poles internally which did/does seem to flatten the extreme hf well. Not an issue for me, but I'd go for a Super body myself and out whatever stylus I have available into it

The OM5e was described as a but 'meh' at the time, but I never minded it as a safe standard inexpensive pickup. The OM20 was my favourite I remember for upgrading the OM model in the Dual 505 decks, but the stylus now is very expensive compared to what I regard as superior results from AT's VM95 series, but ymmv of course

For evidence, I'll try to do a scan of one such period review to show where I'm at here.

 

[dlaloum]

I'm talking a physical resonance in the BODY DESIGN, not electrical characteristics here and in the plots done back then, all half inch mount OM models seemed to exhibit it - a response glitch plus separation notch at similar frequencies. The 'Super' body I believe has slit poles internally which did/does seem to flatten the extreme hf well. Not an issue for me, but I'd go for a Super body myself and out whatever stylus I have available into it

The OM5e was described as a but 'meh' at the time, but I never minded it as a safe standard inexpensive pickup. The OM20 was my favourite I remember for upgrading the OM model in the Dual 505 decks, but the stylus now is very expensive compared to what I regard as superior results from AT's VM95 series, but ymmv of course

For evidence, I'll try to do a scan of one such period review to show where I'm at here.

From memory the slit poles was an Ortofon version of the laminations in other MM designs, intended to reduce eddy current, and its related HF effects.... but those effects are typically very minor, and totally overwhelmed (by several orders of magnitude) by loading, tip mass etc... (all the other factors).

The Super and non-super bodies I have seen seemed to me to be identical - and the super was also deployed in the concord/banana bodies as well... which seems to imply that this is more about the slit poles and not a body resonance?

I'd be very interested in those period reviews if you can find them!

 

[DSJR]

Measurements admittetly published by Ortofon showed how the 10kHz region upwards was improved by the slit pole pieces. Shure had laminated strips akin to plywood and maybe AT have the same, I'm not sure. Ortofon had the poles as in tubes either whole or slit down their length from memory. Prior to this, the earlier Ortofons had the option of the 'CAP 210' device, two miniature capacitors mounted to a small plate which fitted snuggly around the pins on the back. Again, this little device measurably and audibly improved their better pickups of this period.

 

[dlaloum]

Measurements admittetly published by Ortofon showed how the 10kHz region upwards was improved by the slit pole pieces. Shure had laminated strips akin to plywood and maybe AT have the same, I'm not sure. Ortofon had the poles as in tubes either whole or slit down their length from memory. Prior to this, the earlier Ortofons had the option of the 'CAP 210' device, two miniature capacitors mounted to a small plate which fitted snuggly around the pins on the back. Again, this little device measurably and audibly improved their better pickups of this period.

Yes Shure, and AT had laminations (shure only on the top models as far as I know) - AT seemed to have laminations on all their VM range - including the basic ones, but I believe more laminations on higher end models...

 

[USER]

Professional Re-tipping Example 2: Audio-Technica AT-OC9ML/II
Click to increase size

Original post

Notes

• These are from @mackat and this cartridge was re-tipped with a half-height micro-ridge diamond and "adjusted for optimal channel separation"
  • Initially sent in for a minor body issue (ended up being a loose screw under the sticker) but the diamond broke off during transit
• The second set of measurements has FR corrected to my CA-TRS-1007
• There are a total of two re-tipping examples and each was re-tipped by a different, US-based re-tipper
• We have thought long and hard about how to present these results and decided that we will not name the re-tippers
  • Please don't ask and please don't speculate
• While we don't have measurements of the original condition in this case we can judge the results
• Something went horribly, horribly wrong
  • The downward slope suggests a suspension issue or some issue related to stylus imbalance
    • Did changing the diamond to a shorter one affect this?
  • Mackat felt that too much adhesive was used and that the half-height diamond was susceptible to dust accumulation
    • Is it a changed weight issue?
  • Distortion is completely screwed up
    • Is this the result of the channel separation "optimization?"
      • Obviously with the CBS STR-100 we cannot know the crosstalk results
      • But I am getting lots of hacky GR-Research-type vibes from this
• If you take anything away from this let it be the following: DEMAND MEASUREMENTS FROM RE-TIPPERS
  • Adding this step to a work process is minimal in cost and easy to do for a professional --there is no excuse
    • Heck, there is nothing wrong with a measurement surcharge
    • At the very least a re-tipper should provide evidence of quality work with some examples
  • If you have a cartridge that you really care about and are considering re-tipping in the future, measure it now (and share the results!)
  • You have the power to make the vinyl market better for consumers

With that, spooky week is over. Happy Halloween!

 

[GXAlan]

@USER great updates. For Audio Technica, is third party retipping considerably cheaper than the factory trade in program?

 

[USER]

@USER great updates. For Audio Technica, is third party retipping considerably cheaper than the factory trade in program?

Thanks. As far as your question goes, I have no idea. Hopefully someone else can chime in. A quick looks shows that Audio-Technica really, really does not want you going an unauthorized re-tipper. I myself have never considered re-tipping because I have never seen any real evidence of its efficacy. I have a serious mistrust of vinyl forums -- for good reason, and why I am trying to help push these measurements -- and so random positive reviews (always subjective) have never piqued my interest in the slightest. Hopefully we can get better (and more conclusive) measurements posted on the library. And hopefully re-tippers will start using this fabulous script to aid them with their work.

 

[GXAlan]

Thanks. As far as your question goes, I have no idea. Hopefully someone else can chime in. A quick looks shows that Audio-Technica really, really does not want you going an unauthorized re-tipper. I myself have never considered re-tipping because I have never seen any real evidence of its efficacy. I have a serious mistrust of vinyl forums -- for good reason, and why I am trying to help push these measurements -- and so random positive reviews (always subjective) have never piqued my interest in the slightest. Hopefully we can get better (and more conclusive) measurements posted on the library. And hopefully re-tippers will start using this fabulous script to aid them with their work.

What are the current Audio-Technica MC cartridge trade-in values?

Anyone have the latest list from Audio-Technica with trade-in value of the cartridges? Getting ready to trade-in another OC9XML but haven't checked...

forums.stevehoffman.tv

And for comparison the trade in cost for Audio Technica is
AT-OC9XEB $123.47
AT-OC9XEN $178.79
AT-OC9XML $281.79
AT-OC9XSH $332.80
AT-OC9XSL $375.74

Which seems pretty reasonable to me…

 

[aaaakkkk]

Professional Re-tipping Example 2: Audio-Technica AT-OC9ML/II
Click to increase size
View attachment 322603View attachment 322604
View attachment 322606View attachment 322608
Original post

Notes

• These are from @mackat and this cartridge was re-tipped with a half-height micro-ridge diamond and "adjusted for optimal channel separation"
  • Initially sent in for a minor body issue (ended up being loose screw under the sticker) but the diamond broke off during transit
• The second set of measurements has FR corrected to my CA-TRS-1007
• There are a total of two re-tipping examples and each was re-tipped by a different, US-based re-tipper
• We have thought long and hard about how to present these results and decided that we will not name the re-tippers
  • Please don't ask and please don't speculate
• While we don't have measurements of the original condition in this case we can judge the results
• Something went horribly, horribly wrong
  • The downward slope suggests a suspension issue
    • Did changing the diamond to a smaller one affect this?
    • Mackat felt that too much adhesive was used and that the half-height diamond was susceptible to dust accumulation
  • Distortion is completely screwed up
    • Is this the result of the channel separation "optimization?"
      • Obviously with the CBS STR-100 we cannot know the crosstalk results
      • But I am getting lots of hacky GR-Research-type vibes from this
• If you take anything away from this let it be the following: DEMAND MEASUREMENTS FROM RE-TIPPERS
  • Adding this step to a work process is minimal in cost and easy to do for a professional --there is no excuse
    • Heck, there is nothing wrong with a measurement surcharge
    • At the very least a re-tipper should provide evidence of quality work with some examples
  • If you have a cartridge that you really care about and are considering re-tipping in the future, measure it now (and share the results!)
  • You have the power to make the vinyl market better for consumers

With that, spooky week is over. Happy Halloween!

I can’t imagine how you can get a roll-off in the frequency response on the AT-OC9ML/II, any change in the mass of the cantilever leads to an increase in the frequency response, I had several re-tipped MCs, everywhere there was a rise of 6-15 dB at 20 kHz.

 

[dlaloum]

I can’t imagine how you can get a roll-off in the frequency response on the AT-OC9ML/II, any change in the mass of the cantilever leads to an increase in the frequency response, I had several re-tipped MCs, everywhere there was a rise of 6-15 dB at 20 kHz.

If the effective tip mass rises, the resonant frequency of the cantilever will drop ... the reduction in peak frequency, may result in a rise in HF response - depending on where it was originally and where it ends up....

 

[aaaakkkk]

• this cartridge was re-tipped with a half-height micro-ridge diamond

Does this re-tipp look like this photo?

 

[dlaloum]

Does this re-tipp look like this photo?

Lovely picture... but that looks like factory original rather than retip?

 

[aaaakkkk]

Lovely picture... but that looks like factory original rather than retip?

I'm surprised by the tail of the diamond that sticks out from the other side of the cantilever. And if there is a half-height micro-ridge diamond, then they probably usually install a full-height micro-ridge diamond. Or is it just mounted at half height?

 

[USER]

Test Record Wear Measurements

Historically it has been thought that test records have a relatively short lifespan as wear alters the frequency response, notably in the higher frequencies. Indeed one of my most trusted sources provides an example of significant record wear occurring well before 40 plays. See the record wear article from Stereo Review 1976, Issue 7 for more information. Edit: to be fair, their results are not fully conclusive as they note the many variables that come into play when playing and testing a record and the many variables that can effect record and stylus wear.

So far I have not seen much evidence pointing to such a limited lifespan in my measurements, including those of known worn-out cartridges. I have only seen this phenomenon when I damaged a test record with a destroyed diamond tip. The effect looked pretty much the same as above, so damage does show up like how the article explains and the first place to look is the in higher frequencies. I re-measure my Shure V15 V-MR from time to time to make sure my CA-TRS-1007 results are consistent (at least with respect to each other). It is the flattest cartridge I own so it is the perfect one for such a test. I have done this with my older, now retired CBS test record as well and have made numerous posts showing the results these past few years. Here is the last one.

CBS STR-100 after 100 measurements. I am confident the difference is due to small discrepancies in set-up.

Damaged CA-TRS-1007. See these posts for information. I initially thought the difference was due to the use of a servo-tonearm. The results are consistent with all cartridges and seem comparable to the wear example above.

Of course these are not the most rigorous tests as I am measuring cartridges of various diamond shapes and at different tracking forces below 2g. More, test records may have different physical properties and thus some may be more susceptible to wear than others, but here are two examples of the test records most likely to be used in this library. I highly recommend having a control cartridge to create a master measurements graph and then confirm test record condition every once in a while in order to have confidence in your results.

Here is the original measurement of my Shure V15 V-MR, taken on June 30, 2023. Ignore the date on the graph, that is the date I processed that particular graph.

Here is one take today, November 01, 2023.

As you can see FR has not been affected by wear at this point. This test record has well over 100 measurements on it. Note that the measurements show a slight dip on the left channel because azimuth needs further adjustment and this was good enough that I didn't feel the need to re-measure.

So my measurements are consistent so far into this project, which is a relief. It'll be interesting to see when FR becomes affected by wear. Perhaps when I get to my final cartridges as I am saving all the ones that need higher tracking force until the end. But that is still several months away .

 

[Thomas_A]

Test Record Wear Measurements

Historically it has been thought that test records have a relatively short lifespan as wear alters the frequency response well before 40 plays. Indeed one of my most trusted sources says so. See this example from Stereo Review 1976, Issue 7.

So far I have not seen much evidence pointing to such a limited lifespan in my measurements, including those of known worn-out cartridges. I have only seen this phenomenon when I damaged a test record with a destroyed diamond tip. The effect looked pretty much the same as above, so damage does show up like how the article explains and the first place to look is the in higher frequencies. I re-measure my Shure V15 V-MR from time to time to make sure my CA-TRS-1007 results are consistent (at least with respect to each other). It is the flattest cartridge I own so it is the perfect one for such a test. I have done this with my older, now retired CBS test record as well and have made numerous posts showing the results these past few years. Here is the last one.

CBS STR-100 after 100 measurements. I am confident the difference is due to small discrepancies in set-up.

Damaged CA-TRS-1007. See these posts for information. I initially thought the difference was due to the use of a servo-tonearm. The results are consistent with all cartridges.

Of course these are not the most rigorous tests as I am measuring cartridges of various diamond shapes and a at different tracking forces. More, test records may have different physical properties and thus some may be more susceptible to wear than others, but here are two examples of the test records most likely to be used in this library. I highly recommend having a control cartridge to create a master measurements graph and then confirm test record condition every once in a while in order to have confidence in your results.

Here is the original measurement of my Shure V15 V-MR, taken at the end of June, 2023. Ignore the date on the graph, that is the date I processed that particular graph.
View attachment 323060
Here is one take today, November 01, 2023.
View attachment 323061
As you can see FR has not been affected by wear at this point. This test record has well over 100 measurements on it. Note that the measurements show a slight dip on the left channel because azimuth needs further adjustment and this was good enough that I didn't feel the need to re-measure.

So my measurements are consistent so far into this project, which is a relief. It'll be interesting to see when FR becomes affected by wear. Perhaps when I get to my final cartridges as I am saving all the ones that need higher tracking force until the end. But that is still several months away .

From Rays first wear experiment I did some comparisons and it was only a tiny drop at high frequencies from the record. I don’t have the link now but I can try look up.

 

[JP]

https://www.worldradiohistory.com/Archive-All-Audio/Archive-HiFI-Stereo/70s/HiFi-Stereo-Review-1976-07.pdf#page=58

 

[Thomas_A]

On this page I made some comparisons with Rays first experiment, repeated playing on same record for 480 hours, approx 1300 plays:

The Finish Line for your Phono Cartridge- Stylus Wear by Mike Bodell

Comparing the new vs worn cartridge on new record, you can see that the worn cartridge has slightly higher output (probably just cartridge to cartridge...

forums.stevehoffman.tv

Stylus (old vs. new) did not really differ, while record (old vs. new) had dropped ≈1-2 dB >10 kHz.