One VR adjust two channel volume.

One variable resistor to control two channel BALANCE, easy, "one variable resistor to control two channel volume", not so easy.

But lots of different ways... perhaps the easiest: use a single pot, A/D, control two digital pots.

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

Please advice TI 1742 can do that or not.

Thank you very much.

It seems that will affect the AV output sepc? right?

use audio ampilifier is cheaper or opamp by myself is cheaper?

Thank you very much.

Best regards, Boki.

Ya, I got it.

Coudl you please advice:

1. the cheapest AD for this application.
2. Does that effect the AV output spec? is that alright?

Best regards, Boki.

Do you literally mean "variable resistor," or is it a potentiometer with a wiper? I assume you mean potentiometer.

In any case, you can use a Voltage controlled amplifier. For example the SSM2164.

The variable resistor would be used to set the control Voltage for the SSM2164. You will probably need to buffer the Voltage as the control inputs on the SSM2165 apparently have a 4k input impedance.

HTH.

--Mac

Oh come on now !

A dual pot is simpler ! It can all be done 'analoguely'. ;-)

If you want to do it with a single pot, then you digitise the pot setting and use it send a control word to your DAC.

Graham

Yes it has a built-in digitally controlled attenuator. You may not have a spare ADC to read a pot though.

Using a simple 'volume control' arrangement may be a lot simpler though !

I hope you know how to do that !

Graham

Use 2 analog multipliers. The "variable resistor" could control the dc input to the x(y) input to both multipliers. The audio input would go to the individual y(x) inputs of the multipliers. This would only work well for high level signals. Otherwise, noise would be a problem. This is an expensive solution.

You need a log tapered stereo pot to control 2 channel volume. Or else you can use a dual digital pot and up/down push buttons.

His DAC has an inbuilt programmable attenuator that can control output volume so doesn't really need any extra devices in the signal path.

Graham

Ah. Now I see that there is a relevant history to this question which precedes this thread. My apologies.

--Mac