Volume control for balanced inputs
 

Have a Ventus that currently uses single ended input with an individual volume control for each channel. (Old ears need more adjustments!) Am switching to Opus to drive it and am uncertain as to how to wire pots when using balanced input. Any help for the newby/old guy?
Pete

If you are feeding a balanced output into a balanced input, you can build a volume control using a dual (stereo) pot for each channel.
It's wired just like any other level control pot. The + preamp output goes through one section and the - preamp output goes through the other section.
Do the same for the other channel.
There are other methods if you can afford to lose some audio level between your preamp and your power amp.

I would use a Volumite for the Opus. Cheaper, easier and better.

Frank; Thanks for the info--I wondered if the dual pot was necessary---also have some concern over the tracking error between pot halves and what effect it might have.
Brian; I will start out with Volumite and see what my "earspeakers" tell me. By the way, any idea when the SPDIF module will come available again? It and volumite are the last links in the chain for my headamp.

Pete

Spdif modules will be available in a couple weeks (waiting on a batch of boards)

Using a dual pot on balanced input will totally destroy common mode rejection ratio.

Mike

No it will not.
The circuit remains balanced.

This is the schematic for a balanced attenuator.
Input and output remain balanced.

To retain high common mode rejection ratio the resistances must be matched to high precision, that's not going to happen with pots in there.

It's line level.
In the real world, the slight difference in resistance between the + and - legs of the attenuator will not be a problem.