Calling for help with ohm’s law

[chris ma]

When studying amp schematics, I often see a single resistor in the feedback path. This single value resistor must have a definite effect for a particular band of frequencies. Certain frequency may react differently when facing this resistor, some may pass thru some may not, is this assumption correct?

I need help to explain the what if questions in my head lately for example;
A single resistor with a value of 220 in the feedback path replace by three different values resistors in parallel to get the same resultant overall value of 220 too (1k, 500 and 647).
Or 1/220 = 1/1000 + 1/500 + 1/647

Will certain frequency within the band goes thru different resistors which correspond to the easiest path thru a particular value resistor?

Would there be any advantage using multiple value resistors rather than a single resistor in the feedback path? I wonder what differences it may have with the sonic of the amprefier.

Thanks in advance
Chris

 

[roddyama]

Hi Chris,

The resistor(s) are not (ideally) frequency dependent. The frequency dependence will be provided by capacitance in the feedback circuit. So, for typical resistors, it will not matter how many series/parallel combinations you use, the effects will be the same as a single resistor of a value equal to the resistance of the combination.

Rodd Yamashita

 

[chris ma]

Thanks Rodd