Goldpoint SA2X - Nobsound NS-05P passive attenuator comparison technical measurements

Discussion in 'Portable and Other Gear Measurements' started by atomicbob, Jan 10, 2019.

  1. atomicbob

    atomicbob dScope Yoda

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    PSA: Nobsound NS-05P specifications on Amazon were updated and now show impedance as 10K.

    So another was acquired and measured for DC resistance. Unfortunately the unit received measures approximately 50K. My guess is there is a bit of stock to be sold (flushed) before the change takes effect. Unit returned.

    Buyer beware.
     
    FlySweep, rlow, Soups and 4 others like this.
  2. ultrabike

    ultrabike Measurbator - Admin

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    LOL!!!!
    I have not measured the unit u sent me. I will soon.
     
  3. RatSalad

    RatSalad Facebook Friend

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    I wonder if there's any with 10k yet I would order one ...
     
  4. rlow

    rlow A happy woofer

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    I was thinking about grabbing a Nobsound from Amazon as well, but not sure about the 50k pot issue. I’m not clear from previous posts (sorry if I missed it) but I assume there is no way to just eyeball whether you have the 10k pot version based on a number or something on the pot? It has to be measured to determine it? The pic from @atomicbob from the top of the inside of the unit doesn’t seem to show it...
     
    Last edited: Mar 12, 2019
  5. atomicbob

    atomicbob dScope Yoda

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    rlow likes this.
  6. bilboda

    bilboda Friend

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    Got the nobsound for my LP. So nice to have more than 2 degrees available on the dial for the Clears.
    Both pots at 10 0'clockish. FWIW, a lil slip of paper says 20K, but it's 50K
     
  7. Scorob

    Scorob Rando

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    atomicbob,

    I’m currently using a Nobsound 50k. I need a lot of attenuation, so I normally set the pot at 9 o’clock. I’m guessing this is around 30db. You mentioned that at more than 20db, frequency rolloff should not be an issue with the Nobsound. That’s good.

    However, I’m not totally clear on all the other differences (gain linearity, crosstalk, residual noise, transient response, channel imbalance).

    Could you say if these are dependent on:

    1) The level of attenuation
    2) Size of the pot
    3) Quality of the pot

    I don’t really have a choice on the size of the pot, or the level of attenuation. However, I would be happy to change it for a higher quality 50k pot if It addresses these differences.
     
  8. Shplad

    Shplad Rando

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    atomicbob/anyone:

    I'm trying to measure the resistance as you described in post #25 above, and am getting different numbers. I'm getting:

    Pins 1 - 2 9K
    Pins 1 - 3 8.32K
    Pins 2 - 3 17.59K

    I tried taking the Nobsound apart, but after I remove all the screws, can't figure out how to get the case apart.
    Any suggestions on that as well?

    Thanks.
     
  9. atomicbob

    atomicbob dScope Yoda

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    Level of attenuation has first order effect on frequency response only. The others aren't worth worrying about. Quality of pot has effect on channel imbalance but to reduce channel imbalance requires stepped attenuator with precision resistors. Size of pot matters only if you are planning to run power through the pot which doesn't apply in this situation. The real issue is the pot should be 10K not 50K for best performance between 6 and 20 dB of attenuation.

    It appears you are either measuring the output connectors rather than the input connectors or have something connected to the output while measuring. Measurements should be made with the Nobsound disconnected from everything.
     
  10. Shplad

    Shplad Rando

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    atomicbob:

    Thanks for your reply. I'm definintely measuring the input connectors. Is there something wrong with the POT in my unit?
     

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