That was refered to forr with his suggestion to use Baxandall-Self volume control.
I'm posting my suggestions below, but if you didn't post your complete circuit then discussion is meaningless. If you do post your complete circuit, please be sure to show the power supply, or post a link to the power supply circuit you're using.
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I will use two 9V batteries. I like your suggestion. And I will use it without gain. with R18=R17=22k. Because the output will go to my headphone amp (voltage gain stage and buffer stage.)
As a second projekt i will built this as a headamp with gain. Gain stage->>tone control->Buffer stage.
But at the end I need buffer IC, which one can you advice to me? The problem ist that I cant use a normal buffer like lt1010 lme49600 because they need global feedback.
49600 is unity gain and can be used stand alone. Of course its performance will be much better if included inside the feedback loop of an op amp. DC offset and drift are much better controlled this way.
Just throw another op amp in the mix and make a unity gain buffer with an op amp front end. You won't need feedback resistors or a DC blocking capacitor in the feedback loop for that.
Just throw another op amp in the mix and make a unity gain buffer with an op amp front end. You won't need feedback resistors or a DC blocking capacitor in the feedback loop for that.
I think in this context you're talking about a "driver," so called because it doesn't amplify voltage, but can handle enough current to drive a following stage or device, in this case headphones.
(The same circuit often has different names depending on function. Unity gain on the input is a buffer, on the output it's a driver.)
The NE5532 will drive headphones (contrary to some stories), but at 17ma maximum output it's running on the edge.
Better is the OPA2134, at 35ma out max.
Pretty much king of the hill is the NJM4556, at 70ma out max.
Not to say these are the only possibilities, but they're popular because they'll work.
In all cases drive capacity can be increased by paralleling op amps as shown. More than two op amps can be paralleled (repeat U2b), but whether there's any point is debatable.
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Huh? That would be more like 4558 level. A typical NE5532 has at least as much "oomph" as an OPA213x (actually the latter is somewhat weaker at low supplies like 9 V). Sijosae got 3.5-ish Vpp into 33 ohms out of it (single supply 9, 14.5, 24 V). That's the AD8620 ballpark. NJM5532 is a bit weaker, but still ~30 mA. NJM2114 is a bit more powerful in return. NJM4580 can crank out more than all of that at 14.5/24 V (about 45 mA), though obviously the '4556 remains king of the hill when it comes to output current.
Two paralleled NE5532s give some pretty decent headphone driving capabilities for normal demands.
You might be thinking of the NE5532's "Output short-circuit current" rating. But this is not a meaningful figure because at that point the NE5532 is a...short circuit. That is, it's not controlling anything, it might as well be just a piece of wire.
The 17ma figure I quoted is one I calculated (with considerable contortions). It agrees with other estimates I've seen, and is in the ballpark for other chips of that type. With respect to Mr. Sijosae, his numbers I dunno.
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There are several 4558 chips, it might be best to state which one you mean.
<< what type of capacitor >>
About the most common type of capacitor you see is mylar film, and these are fine for any application. Using more expensive polyester or other types is fine if you want to.
Use ceramics only for small bypass or decoupling capacitors, in the 1uF range. Use them only for the power supply, not for audio.
Do not use tantalums unless the circuit designer calls for them.
Larger values have to be electrolytics. I suggest using those rated at 50 volts, 105 degrees.
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