[sdiy] tube ladder

metasonix at earthlink.net metasonix at earthlink.net
Sun Jun 30 01:23:41 CEST 2002

>I've been studying pentodes and such to see if this
>solves the problem(s). I'm not sure it does. Its the
>current range that is the hangup. A diode can vary its
>current over several decades and still operate. I
>don't see a pentode yielding that king of range. 

What do you mean? True, a typical small signal tube
cathode is only good for 10-20 mA at charge limit.
They can go down into microamps, even tenths of microamps,
before leakage currents are a problem. Circuit layout,
tube socket insulator material, and other things affect this.

If you're trying to duplicate 10-octave fc sweep ranges found
in conventional solid-state filters, then a tube
ladder probably won't do it. But then the question is, why is
such a huge sweep range so important or critical? Isn't three 
or four octaves enough for musical applications?

E. Barbour

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