Re: How can I make a spk simulator load

Phil Allison wrote:

> "John Stewart"
> > Phil Allison wrote:
> >
> >> >
> >> > About a year & half ago I built a Loud Speaker Simulator very much like
> >> > that shown in Phil's article. For the input L I have a 90 microhenry
> >> > aircore
> >> > choke followed by a 7.5R, 10 watt resistor. The low freqency resonance
> >> > is formed
> >> > by a Mallory 220 microfarad NP motor starting cap in parallel with a
> >> > Hammond
> >> > 159ZC choke ( 60 mh, 0.7R).
> >> >
> >>
> >> ** Such a low value for the input L means you are effectively simulating
> >> a
> >> speaker that has a copper cap ( inductance damper) on the pole piece -
> >> ie
> >> as is commonly used for wide range or twin cone speakers.
> >>
> >> The bass resonance is at 44 Hz but the peak current before saturation is
> >> only 2 amps for the 159ZC, so power input is a bit limited.
> >
> >
> >
> > The rise of impedance caused by the 90 microhenry choke starts at about
> > 4KHz &
> > is well up at 10 KHz, similar to a real speaker.
>
> ** As usual, you are totally wrong.
>
> Your circuit only rises to 9.4 ohms at 10 kHz while typical woofers have
> inductance figures of 0.5 to 2.5 mH - depending on coil size. The impedance
> at 10 kHz is 20 to 30 ohms, unless a copper shorting ring or pole cap is
> fitted.
>
> Then the figures are like your circuit.
>
> ........ Phil

Thankyou for your indication of confidence in my work. I actually measured that
thing & those are the results. Perhaps something else is going on there. But
I've got lots of other things to pursue! Cheers Anyway, John
Stewart


.

Relevant Pages

  • Re: How can I make a spk simulator load
    ... > Phil Allison wrote: ... >>> The rise of impedance caused by the 90 microhenry choke starts at about ... >>> is well up at 10 KHz, ... >> Then the figures are like your circuit. ...
    (rec.audio.tubes)
  • Re: How can I make a spk simulator load
    ... >> Phil Allison wrote: ... > Then the figures are like your circuit. ... it was part of another project for which I was working against a time limit. ... Cheers, John Stewart ...
    (rec.audio.tubes)
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