Cartridge degradation Frequency Response

the thin end of the wedge
Arno P
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Cartridge degradation Frequency Response

Post by Arno P » 06 May 2019 12:04

Hi,

I have been using adjust+ for many years now and I got a question regarding the data I am getting.
My Micro Benz LP cartridges always showed a nice flat curve and currently I see a significant boost of 4..5dB at 20Hz that "shelves down" towards a 0....-2dB at 20kHz.
I double-checked with a second RIAA preamp with similar result.

Could this be the effect of the ageing of the cartridge suspension over years?
Should I doubt the Adjust+ software or audio-card (that I kept the same over all these years)?

Thanks in advance for your answers.

Arno

b+v8an
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Re: Cartridge degradation Frequency Response

Post by b+v8an » 06 May 2019 17:50

Hello Arno P,
I think that you are suffering from too much information.Without knowing more about your cart or setup,the results could be from just about anything ( dirty stylus ? ). If you don't hear anything different ( 20 Hz,really?) I sure wouldn't worry about it. Perhaps someone else could provide more info. Relax....

patient_ot
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Re: Cartridge degradation Frequency Response

Post by patient_ot » 06 May 2019 19:06

I am not super familiar with Adjust+, but I have a general idea of how it works.

Research on cartridges has shown that as they wear, the high frequencies are the first to go. On the CBS STR100, there is something called "playback loss test" that is supposed to be one way to check for a worn stylus.

I think if you suspect something is wrong then getting the cart inspected by the dealer or manufacturer under a microscope is probably the best course of action. How many hours are on this cart?

RE: the sound card, I do not know what you are using. I do know that some sound cards can roll off high frequencies (I ran into this problem before). Some audio analyzer software has a calibration feature to compensate for this. However, if it was a problem with your sound card, I would assume you would've noticed it from day one when you started taking measurements with Adjust+.

Good luck.

Arno P
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Re: Cartridge degradation Frequency Response

Post by Arno P » 07 May 2019 06:15

The sound card crossed my mind here. It does have a calibration feature but for some reason it stays blanked out and new calibration routine acts strange...

Nevertheless, I am curious if someone has data to show the comparison between a new and an old cartridge (same type) tot see how the curve is expected to be altered over years..

patient_ot
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Re: Cartridge degradation Frequency Response

Post by patient_ot » 07 May 2019 15:50

Arno P wrote:
07 May 2019 06:15
The sound card crossed my mind here. It does have a calibration feature but for some reason it stays blanked out and new calibration routine acts strange...

Nevertheless, I am curious if someone has data to show the comparison between a new and an old cartridge (same type) tot see how the curve is expected to be altered over years..
I read that Jico came up with a test that measures distortion at 15khz. They ran this check at different hours of usage and found distortion was significant at 500 hours, then again at 700 hours or so. The longer they ran these tests the nastier things got. Most people will probably not notice the distortion at 500 hours, but it is measurable. Expert Stylus supposedly did similar research. Unfortunately I don't think this was published for the public.

Shure did publish a bunch of papers about cartridges and you can probably find something on stylus wear if you dig around.

Again, if unsure about wear, time for a microscope inspection.

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Re: Cartridge degradation Frequency Response

Post by htk99 » 07 May 2019 16:30

I don't have distortion measurements, but I have a recorded frequency response with the same styli in different condition.

Same new stylus in two different cartridges (of same age ~15 years both) shows no difference between the cartridges.
01_same_stylus_different_cartridge.png
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The new stylus vs old worn stylus shows degradation of high frequency response.
02_three styli_same_cartridge.png
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I was measuring something else (record wear) at the time and this was a bonus, so I didn't pay too much attention to these used styli, but there shouldn't be any error in the graphs. The material played is just a 12" house single, not a test signal of any kind. At least the very worn stylus also distorted audibly.

Arno P
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Re: Cartridge degradation Frequency Response

Post by Arno P » 07 May 2019 17:29

The stylus wear resulting in distortion is one thing.....The thing I am questioning is actually the ageing of the "suspension" / Rubber and the effect on the F-curve (if any).

For my case I did additional adjustments and calibrations and I am getting closer to what I expected, still 4-5 dB rise on the low side, checked with 2 different RIAA pre-amps....hence the question about the suspension

I expect that cartridge manufacturers do have such data but they won't be that open to share it I expect.

patient_ot
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Re: Cartridge degradation Frequency Response

Post by patient_ot » 07 May 2019 20:32

Arno P wrote:
07 May 2019 17:29
The stylus wear resulting in distortion is one thing.....The thing I am questioning is actually the ageing of the "suspension" / Rubber and the effect on the F-curve (if any).

For my case I did additional adjustments and calibrations and I am getting closer to what I expected, still 4-5 dB rise on the low side, checked with 2 different RIAA pre-amps....hence the question about the suspension

I expect that cartridge manufacturers do have such data but they won't be that open to share it I expect.
Hmm, yeah, if Benz does have the data they probably won't share it. Have you noticed any tracking anomalies while playing records? Have you tried contacting Benz? Perhaps they can give you a simple yes or no answer re: the suspension even if they won't share test data.

Arno P
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Re: Cartridge degradation Frequency Response

Post by Arno P » 07 May 2019 20:34

Seems the benz site is rather old (2017?) Still in business I hope

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Re: Cartridge degradation Frequency Response

Post by zlartibartfast » 07 May 2019 22:46

Arno P wrote:
07 May 2019 06:15
The sound card crossed my mind here. It does have a calibration feature but for some reason it stays blanked out and new calibration routine acts strange...
I think that is significant. I suspect your soundcard driver may have been "upgraded" ( I assume you are using Windows) and the calibration feature that once worked is now broken (this is one reason I quit using Windows for anything that matters). Perhaps you can "roll back" your soundcard driver to it's original version?

It may well be that your cartridge is fine and your software is broken.

Arno P
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Re: Cartridge degradation Frequency Response

Post by Arno P » 08 May 2019 06:03

Separately I checked with an oscilloscope and showed the same profile.
Anyhow, I am ok for now on the subject (still very curious about that rubber-ageing-data though ;-) )

In my new Phono-pre (LCR/Tube) I included the option to "shelve-down" the curve on the low fret side in case of the Micro Benz. So measurements look good RIAA +- 0.2dB and in the critical range of 80Hz-20kHz well in the +-0.1dB range..
Irony is always the moment when the cartridge steps in ;-). But as said, compensation for the benz is selectable in my current test setup (plate of spaghetti with 300V on it)...so ready for another round of tests and above all listening

Arno P
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Re: Cartridge degradation Frequency Response

Post by Arno P » 15 May 2019 08:40

Just because I wondered.....Can the compliance of an older mc cartridge be adjusted by tightening the "nut" that pulls on the "piano-string" that puts the pressure on the suspension rubber?

patient_ot
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Re: Cartridge degradation Frequency Response

Post by patient_ot » 16 May 2019 00:36

Arno P wrote:
15 May 2019 08:40
Just because I wondered.....Can the compliance of an older mc cartridge be adjusted by tightening the "nut" that pulls on the "piano-string" that puts the pressure on the suspension rubber?
My understanding is that compliance has more to do with the rubber than just the tension. The stiffness of the suspension rubber usually determines things AFAIK in any cartridge that uses suspension rubber, even MMs and MI carts. It's also a very delicate thing to do with an MC cart...if the tie wire is holding everything together, don't expect it to work if you snap the wire. Any adjustment that is possible needs to be left to an experienced pro IMHO.

Arno P
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Re: Cartridge degradation Frequency Response

Post by Arno P » 16 May 2019 05:50

patient_ot wrote:
16 May 2019 00:36
Arno P wrote:
15 May 2019 08:40
Just because I wondered.....Can the compliance of an older mc cartridge be adjusted by tightening the "nut" that pulls on the "piano-string" that puts the pressure on the suspension rubber?
My understanding is that compliance has more to do with the rubber than just the tension. The stiffness of the suspension rubber usually determines things AFAIK in any cartridge that uses suspension rubber, even MMs and MI carts. It's also a very delicate thing to do with an MC cart...if the tie wire is holding everything together, don't expect it to work if you snap the wire. Any adjustment that is possible needs to be left to an experienced pro IMHO.
Agree with that.
Since all cartridges contain an ageing rubber (some mentioned as non-ageing perhaps), all cartridges would suffer from degradation over time. Since actual data about this is nowhere to be found I expect us as lesser experts to have done some experiments...so the next (and probably my last attempted) question: Did anyone try to rejuvenate an older MC-suspension rubber and did a before/after comparison?

Arno P
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Re: Cartridge degradation Frequency Response

Post by Arno P » 20 May 2019 08:25

Hardly any measurable difference with different phono-pre, cable, VTA, Loading, VTF. Azimuth is ok.

So.....anyone got a clue or similar data of a fresh micro benz wood SL?
Screenshot 2019-05-20 at 09.20.07.png
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