Another Monitor Controller thread!

I know this topic has been discussed several times, and I have read each of these threads several times. However, I still have a few questions. I have been looking at the schmatics over at Gold Point. It has MOST of what I am looking for. I am wanting to build a passive box, and would like to keep it balanced. It will have a five way input selector, two balanced inputs, two unbalanced inputs, and the 5th will be a "none" setting. It also needs to have a stepped attenuator, then I would like to use something similar to the mode select schematic seen here.



1 = STEREO REVERSE
2 = STEREO
3 = MUTE
4 = MONO
5 = LEFT MONO
6 = RIGHT MONO

The next stage would be stereo VU meters, and then finally a three way monitor selection, and an addition two line outs. Can the above schematic be adapted for balanced use? Is it possible to have all of the above features and still keep it passive and balanced? What do you recomend I do to put L and R trims on each of the monitor outs?

Thanks!,
Micah

Anyone? Am I better off unbalancing on the way in, then re-balancing on the way out?

Micah

I couldn't read the value of the resistors...are they 25K? That's pretty high considering that an attenuator following the switching would need to be even higher in order to minimize signal loss through the passive netwoek, and thus the output impedance of the entire system will be very high.

One other "gotcha" in the circuit shown is that the levels (and input impedances) will shift around as you change switch positions.

How important is it to have the mono listening modes be through a purely passive signal path? In a monitor controller I recently built for a mastering studio, the client and I agreed that mono modes were just for compatibility checking, so we opted to use an active summer for those modes.

Then you threw in another monkeywrench..mixture of balanced and unbalanced inputs! The unit I built was designed for ONLY balanced I/O since the Shallco ladder attenuator wouldn't function correctly otherwise.

Bri

They are 22k, yeah, I don't think I am going to pull this off, while staying passive. I need to do more research