[sdiy] The PAiA 2700 VC LPF

[Scott Gravenhorst]

I'm looking at this filter again and it's so simple to 
build, well...  I'd prefer to use parts I have lying
around.  I see that the 2N3391 has a beta of 250.  The
parts I have here are pretty much 2N3904.  Is there a
way to make a 'crippled' darlington pair that could 
increase the 2N3904's beta to 250 ?  I understand that
a simple D-pair will multiply the gains, and I don't
think 10,000 would be right.  My *guess* is that a
resistor between the first transistor's emitter and
the second's base ????  Also, can anyone tell me 
whether this filter is for expo of linear CV?

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-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
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