What good does C5 and R6 on the tone control above do?
Also, does the inverting configuration need a DC bias current return path?
Also, does the inverting configuration need a DC bias current return path?
An externally hosted image should be here but it was not working when we last tested it.
"he probably ment R8 instead of R6"; right, R8 and C5, thanks Mr dreamth, I am indeed wondering what do R8 and C5 do on such circuit, because I saw and breadboarded a similiar circuit without such capacitor and resistor, so, do they do any good or bad?
> I won't be able to hear the difference?
If they offend you, leave them out. Save 37 cents.
My experience is that a rising treble response "may" be benign, or it may catch AM radio, cellfone packet chirps, and other supersonic garbage, big due to treble boost. The amplifier does not know "we only want audio". It will gladly boost radio waves to volts, even though it is a struggle. A struggle which the intended audio may lose (come out garbled). Even 1959 guitar amplifiers had to defend themselves from radio.
If they offend you, leave them out. Save 37 cents.
My experience is that a rising treble response "may" be benign, or it may catch AM radio, cellfone packet chirps, and other supersonic garbage, big due to treble boost. The amplifier does not know "we only want audio". It will gladly boost radio waves to volts, even though it is a struggle. A struggle which the intended audio may lose (come out garbled). Even 1959 guitar amplifiers had to defend themselves from radio.
You always need a DC path for both inputs or the opamp will lockup at full swing (bipolar input), or drift around uncontrollably (FET input).
It has a path through the wiper of that bass control but I don't like it, if the control gets scratchy at all (they eventually do) it'll cause BIG scratches in the output due to momentarily losing DC bias. It should have some separate fixed-resistor path, maybe two 220k's between the wiper and each end of the pot.
Is a 100K, R10, to the inverting input to ground ok for the dc path?
I also change the resistor values in order for a +-12dB at each potentiometer and added a buffer stage.
There is a lot of small details to not-like here.
But many home hi-fis use about this scheme.
It will work fine until gsantosk8 builds something better.