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<DIV><FONT size=2 face="Trebuchet MS"><SPAN
style="WIDOWS: 1; TEXT-TRANSFORM: none; BACKGROUND-COLOR: rgb(239,239,239); TEXT-INDENT: 0px; DISPLAY: inline !important; FONT: 12px/18px verdana, arial, 'sans serif'; WHITE-SPACE: normal; FLOAT: none; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px; -webkit-text-stroke-width: 0px">This
is my restoration of Emu Low Pass 2100 old schematic with v2 1100 submodule...In
my opinion it is not simply a classic moog ladder network implemented with PNP
transistors. There are several variants of design not easy to understand. The
first is the fourth filter cell, which uses a capacitor 1n (the rest are 20n),
disrupting certainly filter properties in resonant mode. The second is the very
low level audio (20mVpp) attacking the input filter, when in moog filters it
ranges from 40 to 100mVpp. The third is the DC levels that sets the separation
points of the filtering cells; while in use moog filters is of the order of 1 to
2V, the Rossum is only 600mV. Zero offset buffers are not identical; the right
one includes a diode whose function is unknown. The differential output pair
(QD102 NPN transistor) has a feedback resistor (47K) that does not exist in moog
NPN versions. I feel this circuit operation hides some secrets that are not
visible at first glance. It will be interesting to find out why these variants
... Suggestions and comments are welcome.</SPAN><SPAN
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class=Apple-converted-space> </SPAN></SPAN></FONT></DIV>
<DIV><FONT size=2 face="Trebuchet MS"><SPAN
style="WIDOWS: 1; TEXT-TRANSFORM: none; BACKGROUND-COLOR: rgb(239,239,239); TEXT-INDENT: 0px; DISPLAY: inline !important; FONT: 12px/18px verdana, arial, 'sans serif'; WHITE-SPACE: normal; FLOAT: none; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px; -webkit-text-stroke-width: 0px"><SPAN
class=Apple-converted-space>See schematic at
:http://electro-music.com/forum/topic-67563.html</SPAN></SPAN></FONT></DIV><br /> <table style="border-top: 1px solid #D3D4DE;">
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