Balanced volume control?

[MWP]

Hi all,

How is balanced line volume control performed?

I havnt looked at balanced schematics before, and have been wondering about it latley for a planned up coming project.

Thanks.

 

[theChris]

i've came up with 1 method, but am unsure if it is logarithmic or linear or something else. basically you have 2 inputs. each input has an input resistor. placed from the ends of these two resistors are the outputs, and a variable resistance from the ends of the resistors. this creates an attenuation and load on the circuit. note that this circuit is not balenced if the destination is unbalenced and that if the source is not balenced the signal will not be equal in magnitude on each line.

 

[theChris]

pic. pretty sure it should work. make sure the preamp can drive the twice the input resistor, this likely means you will need a higher input impedance on the amplifer. also, you will need to analyze the volume control with the balenced amplifer application.