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Re: [TCML] The Hammertone Predikter

Hi Terry,

> I wanted to check into this...:

> I checked the numbers on all the Pearson current monitors I have

> The numbers don't seem right so either the meter is too weak
> or the internal 50 ohm resistance of the monitors is messing
> everything up.

Yes, the monitor with have a 50 ohm resistor internally across
the output.  Makes a mess of any attempt to measure Ls by this
method and you're guaranteed get a low Q.

The Pearson data doesn't give Ls, but we can work it out from
the specified low frequency 3dB point.  At that frequency,
XLs = Rs where Rs is the 50 ohm internal load.

Ls = 50/(2*pi*F) ~= 8000/F mH

2100   125Hz  64mH
 110     1Hz   8H
 101  0.25Hz  32H
 411     1Hz   8H
4100   140Hz  57mH

Hmm, these figures might not be correct because that Pearson
web page mentions a 'patented distributed termination' technique.
Paul Nicholson

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