Simple mixer circuitry required

[lurkist]

Hello,

I would like to make a basic 2-channel mixer with a aux/headphone outs.
Please bear with me, as I am pretty much a newbie! Some of my questions may sound obvious, etc.

Firstly take a look at my circuit diagram (or, "Shocked Robot Smoking"!)


Presumably, as volume controls are involved, a pre-amp is needed.

Would this be stright after the Aux ins? (point 1)

So after pre-amping and individually volume controlling, is any extra circuitry needed before mixing? (point 2)

What circuitry is required to change the Aux out into an optional Headphone circuit? (Point 3)


FORGOT IN DIAGRAM-

Master volume control. (Ideally the headphone socket would break the Aux out, unless it's better / less lossy to individually control the volumes)

ThanksgHello,

I would like to make a basic 2-channel mixer with a aux/headphone outs.
Please bear with me, as I am pretty much a newbie! Some of my questions may sound obvious, etc.

Firstly take a look at my circuit diagram (or, "Shocked Robot Smoking"!)


Presumably, as volume controls are involved, a pre-amp is needed.

Would this be stright after the Aux ins? (point 1)

So after pre-amping and individually volume controlling, is any extra circuitry needed before mixing? (point 2)

What circuitry is required to change the Aux out into an optional Headphone circuit? (Point 3)


FORGOT IN DIAGRAM-

Master volume control. (Ideally the headphone socket would break the Aux out, unless it's better / less lossy to individually control the volumes)

Thanks

[clem_o]

Originally posted by lurkist

Presumably, as volume controls are involved, a pre-amp is needed.

Would this be stright after the Aux ins? (point 1)

So after pre-amping and individually volume controlling, is any extra circuitry needed before mixing? (point 2)

What circuitry is required to change the Aux out into an optional Headphone circuit? (Point 3)

1 - yes, you could put a volume control there.

2 - google "Summing amplifier". Any op-amp cookbook will have that circuit, or Horowitz' 'Art of Electronics'...

3 - you can try looking (i.e. google) for a headphone amp - there are several designs floating around, some discrete, some single-chip. You can even have a selector switch wired prior to the headphone amp so that you can choose to monitor either inputs or the mixed output...