Cartridge dynamic behaviour

[scott wurcer]

I think I can do that with what I have on ortofon.

The obvious (?) extreme would be spherical vs. line contact. The can of worms over whether the LP is cut pre-distorted can also be reopened. Good luck finding a definitive answer. IIRC one member here claimed there are way more of those than folks think.

 

[billshurv]

I can't do spherical vs line contact without swapping to DJ stylii which have wildly different compliances. BUT doesn't cost much to get a spherical grafted onto and OM10 which would be worth it for the data.

 

[gpapag]

Therefore, instead of swapping labels I will repeat that test and repost the hopefully correct measurements (double checking not to switch the parallel and series results)

I run that test again on the new jig. On the three cartridges that Bill has sent me.
Same signal level on all three.

Attachment 4 is for Ortofon Super OM10_R ch
Attachment 5 is for Dual ULM65E_R ch
Attachment 6 is for Shure SC35C_R ch

George

 

[gpapag]

With this, I hope I am ending distortion measurements on the stationary part of the motor for the Ortofon Super OM10 cartridge, R ch.
Measurements with the new jig.
Loading is with 47kOhm and the parasitic capacitance of the jig (209pF@100Hz, 199pF@1kHz, 176pF@10kHz, 156pF@100kHz) plus the unknown capacitance of the soundcard’s 1MOhm input.
Attachment 7 is distortion waterfall of the cart with 320mVrms step sine signal.
Attachment 8 is distortion waterfall with a short in place of the cart same signal level.

George

 

[billshurv]

George: You deserve a well earned break to actually listen to some records now!

 

[scott wurcer]

With respect to azimuth issues, last night I ran 3 test LP's in quick succession with left/right/lateral sequences and the results were not encouraging. The crosstalk varied significantly and it looked like setting it up by eye would be as good as anything.

 

[billshurv]

I do wonder if just playing a mono track and analysing it correctly might give you the information you need. Need to think it through but possibly nulling the fundamental and analysing the distortion might yield something.

 

[gpapag]

Distortion measurements on the stationary part of the motor for the Dual ULM65E cartridge, R ch.
Measurements with the new jig.
Loading is with 47kOhm and the parasitic capacitance of the jig (209pF@100Hz, 199pF@1kHz, 176pF@10kHz, 156pF@100kHz) plus the unknown capacitance of the soundcard’s 1MOhm input.
Attachment 7 is distortion waterfall of the cart with 320mVrms step sine signal.
Attachment 8 is distortion waterfall with a short in place of the cart same signal level. distortion measurements

George

 

[gpapag]

Distortion measurements on the stationary part of the motor for the Shure SC35C cartridge, R ch.
Measurements with the new jig.
Loading is with 47kOhm and the parasitic capacitance of the jig (209pF@100Hz, 199pF@1kHz, 176pF@10kHz, 156pF@100kHz) plus the unknown capacitance of the soundcard’s 1MOhm input.
Attachment 7 is distortion waterfall of the cart with 320mVrms step sine signal.
Attachment 8 is distortion waterfall with a short in place of the cart same signal level. distortion measurements

George

 

[gpapag]

Distortion measurements on the stationary part of the motor for the AKG P8ES cartridge, R ch.
Measurements with the new jig.
Loading is with 47kOhm and the parasitic capacitance of the jig (209pF@100Hz, 199pF@1kHz, 176pF@10kHz, 156pF@100kHz) plus the unknown capacitance of the soundcard’s 1MOhm input.

George

 

[gpapag]

Distortion measurements on the stationary part of the motor for the Audio Technica AT100E cartridge, R ch.
Measurements with the new jig.
Loading is with 47kOhm and the parasitic capacitance of the jig (209pF@100Hz, 199pF@1kHz, 176pF@10kHz, 156pF@100kHz) plus the unknown capacitance of the soundcard’s 1MOhm input.

George

 

[gpapag]

Distortion measurements on the stationary part of the motor for the Pickering 950EE/MKII cartridge, L ch.
Measurements with the new jig.
Loading is with 47kOhm and the parasitic capacitance of the jig (209pF@100Hz, 199pF@1kHz, 176pF@10kHz, 156pF@100kHz) plus the unknown capacitance of the soundcard’s 1MOhm input.

George

 

[Hans Polak]

To my disappointment Ortofon has yet not responded to several emails with my friendly questions regarding their test record.

That leaves us to decide on our own whether this CV test record can be used for testing MM cartridges.
JP have you already found some time to play this record with different termination settings ?
To my feeling this record is OK. up to 40 kHz within +/- 1dB when played at 45rpm.
And we also have the preemphased CH Precision record, going within +/- 1dB up to 30 kHz.
When JP can confirm this FR, we could start closing the circle with validated records and equivalent circuits for 8 Carts to find the Tranfer Circuit for the Carts motor function.

Hans

 

[mkc]

I wonder where Ortofon buys the records they use for production test or perhaps they made a lifetime purchase? They apparently doesn't use their own test record.

Ortofon measurement test chain

Mogens

 

[billshurv]

They do state they use their own test record as well as others on that page. They likely have a safe full of the out of print ones tho!

 

[mkc]

Yes, you are right. However, I was thinking of what they write in the section "Three sequences of measurement test".

 

[scott wurcer]

I wonder where Ortofon buys the records they use for production test or perhaps they made a lifetime purchase? They apparently doesn't use their own test record.

Interesting they get 6mo of production testing out of each copy. Contrast that to some who claim 1 or 2 plays and the test LP is shot.

 

[billshurv]

They weren't clear on how many cartridges are run through the rig mind...

 

[gpapag]

Contrast that to some who claim 1 or 2 plays and the test LP is shot.

Give me names and I will make sure they will be banned

George

 

[scott wurcer]

They weren't clear on how many cartridges are run through the rig mind...

Levels of quality control have specified sample rates but do any of their top carts come with serialized individual plots? A $40 Nakamichi microphone capsule did in 1977.