Big muff question?

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Dingleberry
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Post by Dingleberry »

When taking a closer look at the big muff schematics I noticed one thing. The third transistor driving tone control has actually a parallel dc path to ground trough 20k resistor - 100k tone pot - 22k resistor. Will that affect the transistor bias/operation somehow and will that be audible? Is that a mistake from engineer or is it just the way the engineer wanted? In some BM clones/variants the tone control network is dc isolated trough 1uf cap. Anyone using spice circuit modeller willing to take a challenge? Would be nice to see how that added parallel 142k resistance changes the operation point of that transistor or will there be almost any change?
-T
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mini
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Post by mini »

Built a similar circuit recently, and wondered the same. Tried both options, measured and watched the results on the scope in DC mode and listened closely while shorting the cap with a wire: no difference! Seems like the shunting impedance is high enough not to interfere with the voltages. Saves a cap, and the highpass caused by a potential cap seems out of the audible range.
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