Grubb
Well-known member
One of my favourite circuits is the Mach 1/Southern Belle, which I have enjoyed building and messing around with. I'm trying to understand how parts of the circuit work, with an eye to potential mods. Below is the first section common to both circuits, taken from the SB build docs:
I think I mostly understand the negative feedback loop, the purpose of C5, and the clipping diodes. At least in functional terms.
I think R6 and the Drive pot are setting RF for this amplifier circuit.
What I don't yet understand well is what C3, C4, R8 and R9 are doing. I am anticipating that R8 and possibly R9 are involved in setting RIN and that there are some filters at work here, because this is where the Timmy bass control is. I would love it if someone could help me grasp what is going on here.
I think I mostly understand the negative feedback loop, the purpose of C5, and the clipping diodes. At least in functional terms.
I think R6 and the Drive pot are setting RF for this amplifier circuit.
What I don't yet understand well is what C3, C4, R8 and R9 are doing. I am anticipating that R8 and possibly R9 are involved in setting RIN and that there are some filters at work here, because this is where the Timmy bass control is. I would love it if someone could help me grasp what is going on here.
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