Hello!
I'll do my best to answer in-line with your questions.
>Can someone tell me what happens if you connect two pairs of amps to a >passive pre-amp like the NOH?
The load would be the combined impedance of the 2 loads. Most loads are high enough that this works fine and I often bi-amp myself. If you had a 50K load at each amp the net load would be 25K as an example.
>What does this do to input and ouput impedance considerations?
See above - not usually any special considderations unless the amps both had very low input impedances already (like 5K or something...)
> Are there any advantages/ disadvantages compared to running only one >pair of amps at a time?
Again - not really. If your system is setup to bi-amp then you'd bi-amp!
>Also, how does balanced operation (with the XLRs) work?
Pretty good.
>Is it possible to receive a single ended input and send the same signal >through balanced outputs?
Yes it is. Transformers are often used just to do these kind of unballanced to ballanced or ballanced to unballanced conversions.
>Would the signal that goes out be truly balanced? Aren't the hot legs of a
>balanced line supposed to be equal and opposite to each other? If this is
>true, wouldn't you need four transformers for each of the lines in a stereo
> setup?
Kinda.... Ballanced lines are also known as differential signals - with the idea being that the actual signal is the difference between pin2 and pin3 of the ballanced signal. That way if some noise appears on both lines then the difference stays the same - cancelling out the noise. The output of a TX102 is what is known as a floating ballanced signal. It does not have a true center tap for a ground reference but the bal amp input see's the difference between the bottom side of the secondary and the top. To add a ground reference would add another wire for EACH of the 23 secondary taps (and the switching for those wires). This would not be an easy task since it is already a lot of wires comming out of those things...
I (and some others) have used TX102's ballanced with my Atmasphere amps with very good success. Many other ballanced amps have been used as well and Jonathan at S&B often runs ballanced connections with his setup over there.
>I'm asking all this because I'm considering bi-amping my speakers and I
>dislike pre-amps. I also have amps that work best from balanced inputs.
>I'm thinking the NOH just might be the answer to my problems.
May be. Call or e-mail with your systems description and we'll see if it would be a fit for what you need.
Many Thanks!
John Chapman
www.bentaudio.com
