Checking Cross talk with Oscilloscope and other things

Discussion in 'Turntables' started by Nashou66, Apr 11, 2018.

  1. Nashou66

    Nashou66 AK Subscriber Subscriber

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    So I recently did a re tip of an Acutex stylus with a Shibata tip and also an Entre' EC-20 with an generic elliptical.

    I wanted to see how well I got the azimuth right of the cantilever/stylus assembly . Listing and visual inspection can only go so far. So I thought i'd finally pull out my O'scope and put it to use
    on my Acutex re tip. Before I pulled out the scope I wasn't happy with the alignment so I re did it a few times ( you can adjust the alignment a bit on these styli ) till I got it as best I could with visual inspection.

    First let me say using the Analog Productions test disc right after the initial re tip left the balance to be desired. It seemed way off. after a few re visits tot he work bench it got much better but I am at my limits adjusting the stylus assembly with out removing the cantilever and doing it over. Have not tried to remove super glue before on a stylus and not sure I want to with the delicate suspension components right there to be exposed to the acetone.

    So now to the three O'Scope pictures I took. Its not to bad. A little louder right channel but nothing you can tell and with an adjustable head shell you might be able to dial out any imbalence , I'm testing on my AR XA . no adjustment for azimuth here. But I do have to re visit with different VTF as these Tri Pole designed carts
    are fussy to VTF and channel seperation .

    First is both channels with a 1 kHz sine wave. .2 volt/div and .5 sec/div

    [​IMG]

    here is the left channel signal only and the right crosstalk below , not to bad I think.

    [​IMG]

    And the Right signal with Left crosstalk.

    [​IMG]

    Pretty cool I think.

    So what else in Cartridge set up can you do with an O'Scope guys?

    Athanasios
     
    Last edited: Apr 12, 2018

     

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  2. JP

    JP 7480 74111110101115

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    Not bad at all. Nicely done.
     
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  3. c_dk

    c_dk Addicted Member

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    Anti skate, tracking ability, channel seperation for the whole frequency response of the cartridge, frequency response linearity, basically with the correct test records all parameters of proper cartridge calibration.
     
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  4. JP

    JP 7480 74111110101115

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    There's a Linear Audio article that details a lot about turntable setup and covers scope usage pretty well IIRC. All the info is out there, but it's nice to have it in one place. My copies are at the house - will try to find which one this weekend.
     
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  5. c_dk

    c_dk Addicted Member

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    While I continue to use the same Tectronics scope I've used with my Sound Technology distortion analyser for 40 years, I have been experimenting with a laptop based scope for cartridge calibration.
     
  6. JP

    JP 7480 74111110101115

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    Via sound card or proprietary hardware?
     

     

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  7. c_dk

    c_dk Addicted Member

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    Cheap Berringer USB sound card. Have fed it with my Shure C-pek as well as a preamp phono stage. Still have all my 40 year old test records but have been experimenting with some modern replacements.
     
  8. JP

    JP 7480 74111110101115

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    I bought a "normalizer" kit. It makes the output around 1v which is the most linear range for a lot of prosumer external sound cards, like the Scarlet 2i2. Supposedly you can get very close to dScope level instrumentation, says the guy who designed it, that also owns a dScope. Hope to play with it soon.
     
  9. c_dk

    c_dk Addicted Member

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    Not trying to unravel or unpack complex analog data streams......for evaluating RIAA compliance a known phono stage and my Soundtech 1701 does that job.

    Have been experimenting with unraveling the noise spectrum of 40 year old vintage preamps with it though has been interesting. I still use my old passive reverse RIAA circuit for this test.
     
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  10. JP

    JP 7480 74111110101115

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    Ah. I do RIAA in the digital domain.
     
  11. Nashou66

    Nashou66 AK Subscriber Subscriber

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    Or you can do this !!!!!.................




    :D

    Nashou
     

     

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  12. needlestein

    needlestein AK Subscriber Subscriber

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  13. Thomas_AA

    Thomas_AA Active Member

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    Note that the results that you get is dependent on the test record that you use...
     
  14. c_dk

    c_dk Addicted Member

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    The first steps of any testing procedure is to correlate how your past measurement procedures compare to your new attempts.

    My test records go back to 1978 so I have been comparing some newly available test records with the industry's old standards.

    It is not only the records themselves that are getting old, just like when the records are worn out those of us who learned how to use them, most often taught to us by those who started the high end audio business, well, we are getting worn out too.

    Most of my vintage test records sat fallow for most of twenty years......no client interest for the most part.

    I have been gathering new pressings to compare to the old and when I have found viable alternatives trying to pass on those that best measure up.
     
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  15. JP

    JP 7480 74111110101115

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    There's a thread on diyAudio about test records you may be interested in.
     
  16. lini

    lini just me...

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    N66: Looks like about a 10:8 ratio and hence a difference of ca. 2 dB - so quite ok, I'd say.

    Greetings from Munich!

    Manfred / lini
     
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  17. Nashou66

    Nashou66 AK Subscriber Subscriber

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    Yes It does sound good to my ears.

    I wish I pulled out the scope when I could hear the difference and took screen shots of that.

    The Analog Productions Disc is pretty useful. It also has a Distortion test but I need an analyzer for that.

    I have an original STR that might be worn some. I'll take a reading of that later today when I get home from work.

    I should hook up a cd as well with the 1khz sine wave to make sure its not the pre amp section that is off.

    Athansisos
     
  18. damacman

    damacman Blown and Injected Subscriber

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    Sure beats a light organ ...
     
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  19. c_dk

    c_dk Addicted Member

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    Most of the test records out there are feeble attempts to allow a end user to try to judge setup via listening to their speakers. This of coarse adds all the issues of the speaker and it's room interactions to color the process.

    Some of the cartridge suppliers back in the day offered dedicated test records for the trade as well as those intended for home use.

    I have been trying to sort through new releases that might have tracks than can be used with today's test equipment but there very few of them.

    Any suggestions are welcome.
     
  20. Nashou66

    Nashou66 AK Subscriber Subscriber

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    This is the one I use. Click Pic.

    [​IMG]
     
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