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<div>Hey Stepan,</div>
<div>Pretty cool idea!</div>
One thing: (supposedly) part of the fuzz face sound is that due to the circuit’s low input impedance and the relatively high output impedance of guitar pickups, the distortion has a kind of “sagging” sound. This will not happen when you use either a guitar with active pickups, or the output of most synth modules. This might be part of your noise issues.
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<div>The part with the JFET looks wrong to me, but I’m not certain. Shouldn’t the capacitor be in series with the JFET’s source, rather than across the source and drain? The goal here is for DC current through R7 to stabilize Q2, but to let a variable amount of AC current though, so that the amount of degeneration applied to the signal varies. As it is right now, the DC current varies but the AC gain is always on max. I haven’t ever used JFETs in a fuzz that way, personally, but I’m sure someone else will chime in.</div>
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<div>I would suggest biasing IC1A to ground and coupling the output from Q2, rather than having IC1A buffer the voltage from Q2’s collector *before* it’s coupled onto IC1B.</div>
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<div class="matchFont">HTH,<br style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;" />
Walker</div>
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On Apr 30, 2018, 6:53 PM -0500, stepan kayukov <stepan.kayukov@gmail.com>, wrote:<br />
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<div dir="ltr">hello -
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<div>i am new to "synths", i have mainly built guitar pedals in the past. i am currently learning EAGLE, so please excuse my drawing. </div>
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<div>my goal is to bring a distortion pedal design into a +/- 12v system. </div>
<div>i executed the attached design, but it is extremely noisy and i hear a great deal of bleedthrough, even though i have added many bypass capacitors. </div>
<div>it is a "fuzz face" pedal going to a buffer, then going to a coupled inverting amplifier. <span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">the input signal enters the collector of the first transistor after being put through a resistor divider, from 12v to 2v, and then passes through another coupling capacitor. </span></div>
<div>i also attempted to use a JFET around R7/C1, as a means of getting "CV" for the distortion control. this could be improved also probably. </div>
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<div><a href="https://ibb.co/jSnXOn">https://ibb.co/jSnXOn</a><br /></div>
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<div>can anyone help me understand how to isolate this circuit from the rest of my synths? </div>
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<div>thank you,</div>
<div>stepan</div>
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