> the pot itself, doesn´t affect at all at the frequency resnponse?
You don't trust my counting-on-fingers? I don't. Let's see what the idiot computer says.
I think I have set-up your circuit accurately, except I "know" there is some stray capacitance and I assumed 100pFd at the chip input. (It is probably less.)
With the 10K pot-full-up, response "extends to infinity". This is only "true" if V1 is a ZERO impedance source. I should have allowed a few ohms, but even 100 ohms would hardly show a droop on this scale.
With the 10K pot at -4dB, top-response is down 3dB at 706K. The pot makes a difference.
With the 10K pot at -8dB, top-response is down 3dB at 678K.
The idiot computer forgot to run -6dB setting, the worst-case. I figure -3dB at 653KHz, not too different from the -4dB and -8dB results the computer plotted. -3dB at 650KHz is -1dB near 325KHz and -0.5dB near 170KHz, insignificant loss even farrr above the audio range.
BTW, pot at -6dB is also the most-extended bass. But in this case the difference is less than 3% shift of -3dB frequency. I sure can't see it on the full-size graph.
With the 10K pot at -20dB, top-response is down 3dB at 1,780K. In principle, when pot is ALL the way down, "infinite loss", frequency response is again "infinite"... but who can prove it?
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But if we keep the 100pFd, and change the pot to 100K, all those frequency top-limits move down by a factor of 10. We may not care 650KHz or 1,700KHz. We might care about -3dB at 65KHz, because that is -1dB at 33KHz and -0.5dB near 17KHz. Guitar-amps with 1Meg pots can have top-loss that no hi-fi guy would accept.
You don't trust my counting-on-fingers? I don't. Let's see what the idiot computer says.
I think I have set-up your circuit accurately, except I "know" there is some stray capacitance and I assumed 100pFd at the chip input. (It is probably less.)
With the 10K pot-full-up, response "extends to infinity". This is only "true" if V1 is a ZERO impedance source. I should have allowed a few ohms, but even 100 ohms would hardly show a droop on this scale.
With the 10K pot at -4dB, top-response is down 3dB at 706K. The pot makes a difference.
With the 10K pot at -8dB, top-response is down 3dB at 678K.
The idiot computer forgot to run -6dB setting, the worst-case. I figure -3dB at 653KHz, not too different from the -4dB and -8dB results the computer plotted. -3dB at 650KHz is -1dB near 325KHz and -0.5dB near 170KHz, insignificant loss even farrr above the audio range.
BTW, pot at -6dB is also the most-extended bass. But in this case the difference is less than 3% shift of -3dB frequency. I sure can't see it on the full-size graph.
With the 10K pot at -20dB, top-response is down 3dB at 1,780K. In principle, when pot is ALL the way down, "infinite loss", frequency response is again "infinite"... but who can prove it?
__________________________
But if we keep the 100pFd, and change the pot to 100K, all those frequency top-limits move down by a factor of 10. We may not care 650KHz or 1,700KHz. We might care about -3dB at 65KHz, because that is -1dB at 33KHz and -0.5dB near 17KHz. Guitar-amps with 1Meg pots can have top-loss that no hi-fi guy would accept.