[sdiy] Ladder filter pole (little OT)

[Dave Krooshof]

>What drives the Moog ladder is the dynamic properties of
>transistors. He learned to carefully use the dynamic properties of
>tubes in school. The trouble is that tubes follow a different curve
>than the exponential.
Yes. Tube heroes spend a lot of time looking at these curves
while deciding on DC levels. But then the curve is
also dependent on time. The shape of the curve change
as a function of the speed you are changing the x.
It's a pity most tube synths have VCA as the only volume
control, as the way a tube VCO kicks in can be very voicelike.
I found this the most attractive part.

Pity mine takes at least a second after each restart...
:-) I started using vocalcords as a drop in replacementpart.
(DIY info here: http://www.ornl.gov/hgmis/genetics.html :-)


>If you think a tube ladder is silly, then think for a minute on the
>guy that made a tube-based DAC!
>
>I know he did an 8-bit DAC that he hooked to his computers
>parallel-port for test-purposes. His plan was for a stereo 16-bit
>thing. He *knew* it would not give the tube-character, he just wanted
>to do it since it was possible to do it. Go figure... ;O)
>
Wow. I was amazed how much differences there are between DAC's.
I was told it was mainly because of two issues:
clocking and proper voltage per bit; the two things tubes are bad at.
Or they must be the gates to a resitor bank. Hmmm.

Then I'm reminded of the test a 'popular science' magazine
in .nl did in the seventies. They made 3 equally shaped trombones
one of silver, one brass, one iron. The brass sounded the best.
That is: when the musicians were blindfolded, the iron one
sounded the best (all agreed).

Eyes matter while listening. That's why I got a tag I could
stick on my Mac to show off for all who care (me) that I
installed a processor upgrade.

Then I'm getting distracted by a daydream of a ADC schemetic
with tubes. Boy, that'll be way hotter then the DAC !



>You've gotta bend the things a little to learn something.
>
Yup.

Dave
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