Glass Blower
(Summer Circuits 2010 article)

Most guitar pedals obtain a high input impedance simply by using a large resistor at the input of the first opamp, but this generates a good deal of noise due to the input bias current. The Glass Blower avoids this by using a smaller resistance (R2) which is bootstrapped by C2 to an effective value of tens of megohms.
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Materials
Extra info / Update
Correction
September 22, 2010.
On the component layout of the PCB designed by the author (free download # 100165-11.zip), transistor Q2 (2N3906) should be turned 180 degrees.
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