Output question

[JingleJoe]

Short version: How should one combine a voltage divider and capacitor at the output stage of a synth/sound machine in order to remove any DC from the signal?


Long version: I intend to connect my sound machines to amplifiers and mixers but to avoid discombobulating them I intend to capacitively couple their outputs.
However the output voltage of many of my inventions is almost rail to rail, which is just too much for most amplifiers; they prefer around 100mV.
To remedy this I have used a voltage divider, if input voltage is about 10V, then a 10k resistor and 100 ohm resistor form a good enough divider to get the voltage down to a level amplifiers can handle.
However if the output voltage has some DC offset (which it often does) this is also transfered out with the divider.
In what arrangement would one combine a voltage divider and capacitor to get rid of this DC offset but not filter the sound too much?
I was considering perhaps as a high pass filter but then you have a resistor effectively in series with the capacitor which will affect it's reactance, but should one merely adjust the capacitor untill suitable reactance at 20Hz is found?
I have found that a capacitor after the divider sort of works but often there is too much filtering.
What would you chaps suggest?

[Osal]

Hello Jingle, what is the rail to rail of your inventions and what are the amplifiers where you send the signal?

What I would do is a voltage divider with a potentiometer, like output volume control -There will be situations, where you don't want to attenuate the signal-
followed by an op-amp as line driver.
This could be configured as an inverting amplifier with a capacitor in its input. for-example: Rin=33K Rf=33K Cin=0.47uF will cut about 10hZ and a little Cf for stability.
Finally you could add in series with its output a 10uF capacitor with a 100K resistor to ground.

[JingleJoe]

While a potentiometer would be really good I want to keep costs down; two resistors are much cheaper than a potentiometer and an op amp.
Each invention tends to run on different voltages but mostly around 8 to 12 volts single rail. These devices will be used with many different amplifiers, PA systems, mixers, old guitar amps or whatever is to hand.

To clarify, is the attached diagram the circuit you suggested?
(minus the op amp and pot of course, but the two resistors could substitute in this diagram for the pot wired as a voltage divider)

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[Osal]

[JingleJoe]

[richardc64]

You can't generalize that whatever amp that's at hand would be happy with 100mV. I would increase the 100 ohm to 1k. If the resulting voltage is too high you just turn down the volume at the amplifier.

Lose the 100k and put the cap before the 10k.

Reactance, schmeeactance.

[JingleJoe]

[JingleJoe]

The circuit I posted above works beautifully, adding the capacitor before the voltage divider lead to a small amount of distortion. Any cap above 10uF works fine, below that things start to get distorted at the low end, square waves start to turn into saw waves with every other cycle inverted, it's simply not cricket.
Acctually let me check something ...
(5 minutes later)
Yes! Caps as low as 1uF work fine with my circuit posted above, at 1uF there was only very slight distorion at very low frequencies (below 100Hz) at 470nF there was much more distortion.
I love it when a plan comes together.

[EdisonRex]

Yes, that makes sense, because the cap is acting as a high pass filter and the bigger the cap, the lower the Fc. I would have thought 10uF would be fine.

[JingleJoe]