giovanni
Well-known member
Getting back to the 4n7 vs 47n, I simulated the circuit in partsim.com (an online SPICE simulator). I set fuzz, treble, volume to some fixed values and I played with the value of C3. With C3 at 4.7n, the frequency response has two "humps" around 250Hz and 3.9kHz, with gain around 17dB and 14dB respectively, and a -3dB notch around 1.2kHz. There is also a low frequency cutoff around 16Hz (-6dB). With C3 at 47n, the 250Hz hump becomes almost 36dB, the 3.9kHz hump 16dB, the notch +6dB and the cutoff goes down lower than 10Hz. So that explains the increased "humph" and gain when using the higher value cap. But the 4.7n gives an interesting frequency response. Is anybody able to compare to an original model to figure out how it's supposed to sound like? Happy to share the simulation to those interested (it's always possible that I made a mistake).