hello all,

the following example shows the sonic differences of
filtered and unfiltered clock noise in a bbd module.

this example is taken from the a188/1 prototype
with 2048 stages ic.

a small repeating sequence is running through
the a188/1. you hear the pure bbd output without
the original signal (this way the effect can be
recognised best). first comes the unfiltered a188/1.
the clock is swept from high speed to very
low speed and then again back to high speed.
after that you hear the same sequence/sweep,
but now the a188/1 output is filtered by an
a108 lowpass (48 db output). the a108 is swept with the
same voltage as the a188/1. i have carefully adjusted
the filter to make sure that it closes only as much
as necessary to suppress the clock noise.

in the first part the clock noise can be heard loud
and clearly as the clock slows down. the signal falls
apart and is full of aliasing, sounding somewhat like a
bit reduction effect. this is for the experimentalists :-)
in the second part the clock noise is filtered out and
therefore the typical "dulling effect" of a common
analog delay occours. this is for those who want that
lush warm retro-sound :-)

http://www.selfoscillate.de/a100files/a188-1-filtered-clock.mp3
file size: 833 kb

best wishes

ingo