Sunday, January 15, 2023

Why nickel is so yummy.

 Here is a simple set of low frequency plots of steel (red) vs. nickel (blue) with applied signal levels.


This clearly shows that for low level low frequency information retrieval, steel takes a certain amount of energy to "turn on".

11 comments:

  1. Are you posting this to show off your Quantasylum analyzer?

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  2. May you share with us how the measure was performed?

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  3. as daniel noted.... done with the QA402.

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  4. Is there more inductance in the nickel sample?

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    1. The short answer is about 3X more inductance... but that is not the cause of the bass attenuation at low signal levels.
      The nickel version has about 1.7 Hy of primary inductance and my meter would not give a stable reading on the steel unit. Sine that meter samples @ around 100mV I moved to the bridge and @ 10V I measured 700mHy so about 1/3 the inductance. Math says that 0.7Hy puts the -3dB point @ 1Hz so it was clear something else was going on.

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  5. That is interesting! I wonder what the chart would look like if you de-stacked the nickel down to a similar inductance level as the steel. The result could be the nature of the lower overall inductance rather than the metal composition however, maybe not! Possibly that is why Cobalt and the amorphous materials also have the special reputation.

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    1. It is not the absolute inductance that is the cause of this but the variable inductance with applied signal level. You mention the cobalt based laminations and I have seen SUT's wound with Hiperco that showed this exact behavior. A 1V input they would be flat to 10Hz but at 1mV they were -3dB @ 40Hz. This is all related to the initial/low level permeability of the material where nickel is king.

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  6. _Electronics Designers Handbook_, Landee,Davis, Albrechcht 1957 ( my father's copy, glad to have it) in its introduction to magnetic circuits Fig 14.3 shows the generation of the locus of the normal magnetization curve as a result of the hysteresis curves viewed dynamically with signal level, drawn large to illustrate the issue. The value of nickle within steel cores was known before the War, see: Partridge, but only really premium transformers could afford it. The other alternative is to add a big air gap and run single-ended, big penalties in parasitic reactances but monotonic transfer (operation far enough away from the zero-zero point that cores don't effect low signal levels). If it were easy, we wouldn't need D.S. to do it.

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  7. Sorry, I forgot to sign,
    Chris Hornbeck

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  8. Nice, so a 50% permalloy transformer is more revealing for both low level mid-high and low frequencies? ( also maybe tone is more natural)
    what is your opinion about Alnico (nickel) compared to field coil drivers? is alnico far below field coil in low level retrieval?

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