Mic splitter box question

Hi, I`ve been asked by a friend about building a 24 ch mic splitter box to allow for an on stage monitor mixer to be used. I believe that mostly they use audio transformers with dual secondaries. Obviously using some brands of transformer this can be quite expensive.

1. Is there a way to do this without transformers that is any good/cost effective ?
2. What should be the spec of the transformers used ? Are there some of the cheaper OEP ones fopr example that would be suitable ?

Any other thoughts on the subject ?

I think a lot of people get away with passive splits - you can just leave off pin 1 or put in a lift switch. Thats probably the cheapest method - even building 16 Y cables does the trick.

For a two-way split you don't need dual secondaries. One way goes directly to say FOH and supplies phantom power, the other through the transformer to the monitoring desk.

Make sure to check the Jensen papers on this.

IMO lifting pin 1 is not the best idea, I would at least add a switch so that you can ground things if you get RF pickup.

Transformers should have reasonable low DC resistances for low noise--say 100 ohm or lower for both windings together. Good CMRR and magnetic shielding is mandatory. Max. level doesn't need to be that high.

Samuel

Thanks, I`ll look at the Jensen paper.

[quote author="Rob Flinn"]Hi, I`ve been asked by a friend about building a 24 ch mic splitter box to allow for an on stage monitor mixer to be used. [/quote]

just get split snake or make a bunch of Y-Splits