<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE eagle SYSTEM "eagle.dtd">
<eagle version="6.4">
<drawing>
<board>
<plain>
<wire x1="0" y1="0" x2="52.705" y2="0" width="0" layer="20"/>
<wire x1="52.705" y1="0" x2="52.705" y2="50.165" width="0" layer="20"/>
<wire x1="52.705" y1="50.165" x2="52.705" y2="52.705" width="0" layer="20"/>
<wire x1="52.705" y1="52.705" x2="47.625" y2="57.785" width="0" layer="20"/>
<wire x1="47.625" y1="57.785" x2="5.08" y2="57.785" width="0" layer="20"/>
<wire x1="5.08" y1="57.785" x2="0" y2="52.705" width="0" layer="20"/>
<wire x1="0" y1="52.705" x2="0" y2="50.165" width="0" layer="20"/>
<wire x1="0" y1="50.165" x2="0" y2="0" width="0" layer="20"/>
<text>IN</text>
<text>G</text>
<text>OT</text>
<text>BUZZ KILL</text>
<text>L</text>
</plain>
<libraries>
<library name="mb_resistors">
<packages>
<package name="R0207/3">
<description>&lt;b&gt;RESISTOR&lt;/b&gt;&lt;br&gt;
&lt;br&gt;
length: 6mm&lt;br&gt;
format: 0.1" (perfboard)&lt;br&gt;
spacing: 3 holes

&lt;p&gt;This length resistor applies to 1/4 watt metal film.</description>
</package>
</packages>
</library>
<library name="mb_diodes">
<packages>
<package name="DO35-3">
<description>&lt;B&gt;DO-35 0.3" spacing&lt;/B&gt;</description>
</package>
</packages>
</library>
<library name="mb_trans">
<packages>
<package name="TO92-">
</package>
</packages>
</library>
<library name="mb_THAT">
<packages>
<package name="SIL8">
</package>
</packages>
</library>
<library name="capacitors-film">
<packages>
<package name="050X030_025_2">
<description>&lt;b&gt;5mm x 3mm, 0.2" pad spacing&lt;/b&gt;</description>
</package>
</packages>
</library>
<library name="potentiometers">
<packages>
<package name="2262_TRIM">
<description>&lt;b&gt;Potentiometer&lt;/b&gt;&lt;p&gt;
1/4" on-board trim potentiometer</description>
</package>
<package name="PADS_SMALL">
<description>&lt;b&gt;Potentiometer&lt;/b&gt;
&lt;p&gt;3 terminals for circuit board for wires connecting to 3 lugs of pot off-board</description>
</package>
</packages>
</library>
<library name="integrated circuits">
<packages>
<package name="DIL14">
<description>&lt;b&gt;Dual In Line Package&lt;/b&gt;</description>
</package>
<package name="DIL08">
<description>&lt;b&gt;Dual In Line Package&lt;/b&gt;</description>
</package>
</packages>
</library>
<library name="resistors">
<packages>
<package name="R0207/3">
<description>&lt;b&gt;RESISTOR&lt;/b&gt;&lt;br&gt;
&lt;br&gt;
length: 6mm&lt;br&gt;
format: 0.1" (perfboard)&lt;br&gt;
spacing: 3 holes

&lt;p&gt;This length resistor applies to 1/4 watt metal film.</description>
</package>
</packages>
</library>
<library name="diodes">
<packages>
<package name="DO35-3">
<description>&lt;B&gt;DO-35 0.3" spacing&lt;/B&gt;</description>
</package>
<package name="DO41-3">
<description>&lt;b&gt;DO-41 0.3" pad spacing&lt;/b&gt;</description>
</package>
</packages>
</library>
<library name="capacitors-elec">
<description>&lt;b&gt;Capacitors, Polar Electrolytic, Radial &lt;/b&gt;
&lt;ul&gt;
&lt;li&gt;large value capacitors: .22 - 470uF (uF = µF = mF)
&lt;li&gt;often used in power supply filters
&lt;/ul&gt;</description>
<packages>
<package name="050_020_1">
<description>&lt;b&gt;5mm diameter, 2mm lead spacing, 0.1" pad spacing&lt;/b&gt;</description>
</package>
<package name="063_025">
<description>&lt;b&gt;6.3mm diameter, 2.5 mm lead spacing, 0.1" pad spacing&lt;/b&gt;</description>
</package>
</packages>
</library>
<library name="supply pins">
<description>&lt;b&gt;Supply&lt;/b&gt;
&lt;ul&gt;
&lt;li&gt;input, output, ground, and power supply.  
&lt;li&gt;these are used on a schematic for placeholders and on a board for pads for off-board components like jacks.
&lt;/ul&gt;</description>
<packages>
<package name="SQUARE">
<description>&lt;b&gt;Square Pad&lt;/b&gt;
&lt;ul&gt;&lt;li&gt;drill diameter 0.7 mm&lt;/li&gt;&lt;/ul&gt;</description>
</package>
<package name="ROUND">
<description>&lt;b&gt;Round Pad&lt;/b&gt;
&lt;ul&gt;&lt;li&gt;drill diameter 0.7 mm&lt;/li&gt;&lt;/ul&gt;</description>
</package>
</packages>
</library>
<library name="jacks">
<description>&lt;b&gt;Jacks&lt;/b&gt;
&lt;ul&gt;
&lt;li&gt;audio and power jacks
&lt;li&gt;off-board versions and just pads for the circuit board
&lt;/ul&gt;</description>
<packages>
<package name="DC">
</package>
</packages>
</library>
</libraries>
<attributes>
</attributes>
<variantdefs>
</variantdefs>
<elements>
<element name="R1" library="resistors" package="R0207/3" value="1M"/>
<element name="C1" library="capacitors-film" package="050X030_025_2" value="470n"/>
<element name="R2" library="resistors" package="R0207/3" value="1M"/>
<element name="R3" library="resistors" package="R0207/3" value="1k"/>
<element name="C2" library="capacitors-film" package="050X030_025_2" value="100pF"/>
<element name="C3" library="capacitors-elec" package="050_020_1" value="10uF"/>
<element name="R4" library="resistors" package="R0207/3" value="20k"/>
<element name="C4" library="capacitors-film" package="050X030_025_2" value="22pF"/>
<element name="R5" library="resistors" package="R0207/3" value="20k"/>
<element name="R6" library="mb_resistors" package="R0207/3" value="100R"/>
<element name="C5" library="capacitors-elec" package="050_020_1" value="22uF"/>
<element name="R7" library="resistors" package="R0207/3" value="100k"/>
<element name="C6" library="capacitors-film" package="050X030_025_2" value="100n"/>
<element name="R8" library="resistors" package="R0207/3" value="5k1"/>
<element name="D1" library="diodes" package="DO35-3" value="1n914"/>
<element name="D2" library="diodes" package="DO35-3" value="1n914"/>
<element name="R9" library="resistors" package="R0207/3" value="22M"/>
<element name="D3" library="diodes" package="DO35-3" value="1n914"/>
<element name="R10" library="resistors" package="R0207/3" value="10k"/>
<element name="R11" library="resistors" package="R0207/3" value="10k"/>
<element name="D4" library="diodes" package="DO35-3" value="1n914"/>
<element name="R12" library="resistors" package="R0207/3" value="1M"/>
<element name="R13" library="resistors" package="R0207/3" value="100k"/>
<element name="R14" library="resistors" package="R0207/3" value="27k"/>
<element name="R15" library="resistors" package="R0207/3" value="5k1"/>
<element name="Q1" library="mb_trans" package="TO92-" value="2n5551"/>
<element name="R16" library="resistors" package="R0207/3" value="10M"/>
<element name="R17" library="resistors" package="R0207/3" value="100k"/>
<element name="D5" library="mb_diodes" package="DO35-3" value="1n914"/>
<element name="R18" library="resistors" package="R0207/3" value="20k"/>
<element name="R19" library="resistors" package="R0207/3" value="20k"/>
<element name="R20" library="resistors" package="R0207/3" value="20k"/>
<element name="R21" library="resistors" package="R0207/3" value="20k"/>
<element name="R22" library="resistors" package="R0207/3" value="10k"/>
<element name="R23" library="resistors" package="R0207/3" value="68k"/>
<element name="R24" library="resistors" package="R0207/3" value="270k"/>
<element name="R25" library="resistors" package="R0207/3" value="47k"/>
<element name="THRESH" library="potentiometers" package="PADS_SMALL" value="10kB"/>
<element name="R26" library="resistors" package="R0207/3" value="10k"/>
<element name="R27" library="resistors" package="R0207/3" value="20k"/>
<element name="R28" library="resistors" package="R0207/3" value="750R"/>
<element name="R29" library="resistors" package="R0207/3" value="620R"/>
<element name="T1" library="potentiometers" package="2262_TRIM" value="1M"/>
<element name="R30" library="resistors" package="R0207/3" value="1k"/>
<element name="Q2" library="mb_trans" package="TO92-" value="MPSA2222A"/>
<element name="C9" library="capacitors-elec" package="050_020_1" value="1uF"/>
<element name="R31" library="resistors" package="R0207/3" value="200k"/>
<element name="R32" library="resistors" package="R0207/3" value="10k"/>
<element name="D7" library="diodes" package="DO35-3" value="1n914"/>
<element name="D8" library="diodes" package="DO35-3" value="1n914"/>
<element name="D9" library="diodes" package="DO35-3" value="1n914"/>
<element name="R33" library="resistors" package="R0207/3" value="100k"/>
<element name="D10" library="mb_diodes" package="DO35-3" value="1n914"/>
<element name="D11" library="mb_diodes" package="DO35-3" value="1n914"/>
<element name="D12" library="mb_diodes" package="DO35-3" value="1n914"/>
<element name="C10" library="capacitors-elec" package="063_025" value="100uF"/>
<element name="R34" library="resistors" package="R0207/3" value="100k"/>
<element name="C13" library="capacitors-elec" package="050_020_1" value="22uF"/>
<element name="IC2" library="mb_THAT" package="SIL8" value="THAT 2181C"/>
<element name="R35" library="resistors" package="R0207/3" value="20k"/>
<element name="IC4" library="integrated circuits" package="DIL14" value=""/>
<element name="IC3" library="integrated circuits" package="DIL14" value="">
<attribute name="NAME"/>
<attribute name="VALUE"/>
</element>
<element name="IC1" library="integrated circuits" package="DIL08" value=""/>
<element name="C11" library="capacitors-film" package="050X030_025_2" value="100n"/>
<element name="C7" library="capacitors-film" package="050X030_025_2" value="330n"/>
<element name="C8" library="capacitors-film" package="050X030_025_2" value="330n"/>
<element name="U$1" library="supply pins" package="SQUARE" value="PADSQR"/>
<element name="U$2" library="supply pins" package="SQUARE" value="PADSQR"/>
<element name="U$3" library="supply pins" package="ROUND" value="PADRND"/>
<element name="+9V" library="jacks" package="DC" value="DC_MONO"/>
<element name="U$4" library="supply pins" package="SQUARE" value="PADSQR"/>
<element name="D6" library="diodes" package="DO41-3" value="1N5819"/>
<element name="C12" library="capacitors-elec" package="050_020_1" value="10uF"/>
</elements>
<signals>
<signal name="GND">
<contactref element="R1" pad="2"/>
<contactref element="R7" pad="2"/>
<contactref element="R12" pad="2"/>
<contactref element="R16" pad="2"/>
<contactref element="R24" pad="1"/>
<contactref element="THRESH" pad="1"/>
<contactref element="T1" pad="1"/>
<contactref element="C9" pad="-"/>
<contactref element="Q2" pad="3"/>
<contactref element="D9" pad="C"/>
<contactref element="D12" pad="A"/>
<contactref element="D10" pad="A"/>
<contactref element="C10" pad="-"/>
<contactref element="R34" pad="2"/>
<contactref element="C13" pad="-"/>
<contactref element="C11" pad="1"/>
<contactref element="C7" pad="2"/>
<contactref element="C8" pad="2"/>
<contactref element="U$3" pad="1"/>
<contactref element="+9V" pad="S"/>
<contactref element="IC4" pad="11"/>
<contactref element="IC3" pad="11"/>
<contactref element="IC1" pad="4"/>
<contactref element="C12" pad="-"/>
</signal>
<signal name="VB">
<contactref element="R2" pad="1"/>
<contactref element="IC1" pad="5"/>
<contactref element="R14" pad="2"/>
<contactref element="R25" pad="2"/>
<contactref element="R27" pad="2"/>
<contactref element="R29" pad="1"/>
<contactref element="C13" pad="+"/>
<contactref element="IC2" pad="3"/>
<contactref element="IC2" pad="6"/>
<contactref element="C2" pad="2"/>
<contactref element="IC3" pad="12"/>
<contactref element="IC3" pad="10"/>
<contactref element="IC3" pad="2"/>
<contactref element="IC3" pad="1"/>
</signal>
<signal name="N$1">
<contactref element="R3" pad="1"/>
<contactref element="C1" pad="2"/>
<contactref element="R2" pad="2"/>
</signal>
<signal name="N$2">
<contactref element="R3" pad="2"/>
<contactref element="C2" pad="1"/>
<contactref element="IC1" pad="3"/>
</signal>
<signal name="N$3">
<contactref element="C6" pad="1"/>
<contactref element="C3" pad="-"/>
<contactref element="IC1" pad="2"/>
<contactref element="IC1" pad="1"/>
</signal>
<signal name="N$6">
<contactref element="R5" pad="1"/>
<contactref element="C4" pad="1"/>
<contactref element="IC2" pad="8"/>
<contactref element="IC1" pad="6"/>
</signal>
<signal name="N$7">
<contactref element="R5" pad="2"/>
<contactref element="C4" pad="2"/>
<contactref element="R6" pad="1"/>
<contactref element="IC1" pad="7"/>
</signal>
<signal name="N$8">
<contactref element="R6" pad="2"/>
<contactref element="C5" pad="+"/>
</signal>
<signal name="N$10">
<contactref element="C6" pad="2"/>
<contactref element="R8" pad="1"/>
</signal>
<signal name="N$9">
<contactref element="R8" pad="2"/>
<contactref element="D1" pad="A"/>
<contactref element="D2" pad="C"/>
<contactref element="R9" pad="1"/>
<contactref element="IC3" pad="13"/>
</signal>
<signal name="N$12">
<contactref element="D1" pad="C"/>
<contactref element="D2" pad="A"/>
<contactref element="R9" pad="2"/>
<contactref element="R10" pad="1"/>
<contactref element="D3" pad="A"/>
<contactref element="IC3" pad="14"/>
</signal>
<signal name="N$13">
<contactref element="R10" pad="2"/>
<contactref element="R11" pad="1"/>
<contactref element="IC3" pad="9"/>
</signal>
<signal name="N$14">
<contactref element="R11" pad="2"/>
<contactref element="D4" pad="A"/>
<contactref element="IC3" pad="8"/>
</signal>
<signal name="N$15">
<contactref element="D3" pad="C"/>
<contactref element="D4" pad="C"/>
<contactref element="R12" pad="1"/>
<contactref element="IC3" pad="5"/>
<contactref element="C7" pad="1"/>
</signal>
<signal name="N$16">
<contactref element="R13" pad="1"/>
<contactref element="R14" pad="1"/>
<contactref element="IC3" pad="6"/>
</signal>
<signal name="N$17">
<contactref element="R13" pad="2"/>
<contactref element="R15" pad="1"/>
<contactref element="R18" pad="1"/>
<contactref element="IC3" pad="7"/>
</signal>
<signal name="N$11">
<contactref element="R15" pad="2"/>
<contactref element="Q1" pad="2"/>
</signal>
<signal name="N$18">
<contactref element="Q1" pad="3"/>
<contactref element="R16" pad="1"/>
<contactref element="R17" pad="1"/>
<contactref element="IC4" pad="10"/>
<contactref element="C8" pad="1"/>
</signal>
<signal name="N$19">
<contactref element="R17" pad="2"/>
<contactref element="D5" pad="A"/>
</signal>
<signal name="N$20">
<contactref element="D5" pad="C"/>
<contactref element="R19" pad="1"/>
<contactref element="IC4" pad="14"/>
</signal>
<signal name="N$21">
<contactref element="R19" pad="2"/>
<contactref element="R21" pad="2"/>
<contactref element="IC4" pad="13"/>
</signal>
<signal name="N$22">
<contactref element="R18" pad="2"/>
<contactref element="R20" pad="1"/>
<contactref element="IC4" pad="12"/>
</signal>
<signal name="N$23">
<contactref element="R21" pad="1"/>
<contactref element="R22" pad="1"/>
<contactref element="IC4" pad="9"/>
<contactref element="IC4" pad="8"/>
</signal>
<signal name="N$24">
<contactref element="R20" pad="2"/>
<contactref element="Q1" pad="1"/>
<contactref element="R26" pad="2"/>
<contactref element="IC4" pad="6"/>
<contactref element="IC4" pad="7"/>
</signal>
<signal name="N$26">
<contactref element="R23" pad="1"/>
<contactref element="R24" pad="2"/>
<contactref element="R25" pad="1"/>
<contactref element="IC4" pad="5"/>
</signal>
<signal name="N$27">
<contactref element="R23" pad="2"/>
<contactref element="THRESH" pad="2"/>
</signal>
<signal name="+9V">
<contactref element="THRESH" pad="3"/>
<contactref element="T1" pad="3"/>
<contactref element="R32" pad="2"/>
<contactref element="D10" pad="C"/>
<contactref element="D11" pad="C"/>
<contactref element="C10" pad="+"/>
<contactref element="R33" pad="1"/>
<contactref element="IC2" pad="7"/>
<contactref element="IC4" pad="4"/>
<contactref element="IC3" pad="4"/>
<contactref element="IC1" pad="8"/>
<contactref element="C11" pad="2"/>
<contactref element="+9V" pad="T"/>
<contactref element="U$4" pad="1"/>
</signal>
<signal name="N$30">
<contactref element="R35" pad="1"/>
<contactref element="IC4" pad="1"/>
<contactref element="D6" pad="C"/>
</signal>
<signal name="N$31">
<contactref element="R22" pad="2"/>
<contactref element="R27" pad="1"/>
<contactref element="IC4" pad="3"/>
</signal>
<signal name="N$33">
<contactref element="R28" pad="1"/>
<contactref element="R29" pad="2"/>
<contactref element="R30" pad="2"/>
<contactref element="IC2" pad="2"/>
<contactref element="IC2" pad="4"/>
</signal>
<signal name="N$28">
<contactref element="T1" pad="2"/>
<contactref element="R30" pad="1"/>
</signal>
<signal name="N$29">
<contactref element="Q2" pad="1"/>
<contactref element="C9" pad="+"/>
<contactref element="IC2" pad="5"/>
</signal>
<signal name="N$34">
<contactref element="Q2" pad="2"/>
<contactref element="R31" pad="2"/>
</signal>
<signal name="N$35">
<contactref element="R31" pad="1"/>
<contactref element="R32" pad="1"/>
<contactref element="D7" pad="A"/>
</signal>
<signal name="N$36">
<contactref element="D7" pad="C"/>
<contactref element="D8" pad="A"/>
</signal>
<signal name="N$37">
<contactref element="D8" pad="C"/>
<contactref element="D9" pad="A"/>
</signal>
<signal name="N$38">
<contactref element="D11" pad="A"/>
<contactref element="D12" pad="C"/>
</signal>
<signal name="N$40">
<contactref element="R33" pad="2"/>
<contactref element="R34" pad="1"/>
<contactref element="IC3" pad="3"/>
<contactref element="C12" pad="+"/>
</signal>
<signal name="N$5">
<contactref element="R4" pad="2"/>
<contactref element="IC2" pad="1"/>
</signal>
<signal name="N$4">
<contactref element="R4" pad="1"/>
<contactref element="C3" pad="+"/>
</signal>
<signal name="N$39">
<contactref element="R26" pad="1"/>
<contactref element="R35" pad="2"/>
<contactref element="IC4" pad="2"/>
</signal>
<signal name="IN">
<contactref element="C1" pad="1"/>
<contactref element="R1" pad="1"/>
<contactref element="U$1" pad="1"/>
</signal>
<signal name="OUT">
<contactref element="C5" pad="-"/>
<contactref element="R7" pad="1"/>
<contactref element="U$2" pad="1"/>
</signal>
<signal name="N$25">
<contactref element="R28" pad="2"/>
<contactref element="D6" pad="A"/>
</signal>
</signals>
</board>
</drawing>
</eagle>
