The input stages (particularly the divider, marked in RED box in the diagrams enclosed) of JLH1969 and JLH2000 is a bit different, but I don't know the exact difference between the two, especially the purpose of C1/R3 of JLH2000.
I am wondering that may be the introduce of C1/R3 in JLH2000 is related to an acurrate control of frequency range of the input filter? But I am not very clear on the idea or calculations for the values involved.
So can C1 be ommited, given that the power supply is stable (e.g., regulated)?
I was wondering, will C1 has effect in AC analysis, e.g., C1 is to bypass/shortcut RV2 at audio frequencies somehow? And how the value of C1 is determined, etc...
C1 is always used even if the supply is regulated.
R2 and the pot are effectively in parallel and are a total of about 43k ohms. The RC network of them being filtered by the 64uF capacitor can be easily calculated.
C1 is always used even if the supply is regulated.
R2 and the pot are effectively in parallel and are a total of about 43k ohms. The RC network of them being filtered by the 64uF capacitor can be easily calculated.