"John Stewart"


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.



........... Phil