If you split it with a really good transformer, you're probably not going to overload it and maybe a T-pad switch will suffice on the input side, and it leaves all the voodoo of the input stage of the mic preamp to the various destinations. "Balanced" also has different performace parameters. "low impedanc" has severl alternate specs. They can even tell you exaclty how to make the perfect network to receive or drive long lines of your choice. They're essential if the parking lot has big trucks with big CB linears, and the lighting dimmer packs are putting square waves on all the AC lines which are crude generator or inverter outputs when at their best. For real pro PA work transformers are good things, not bad. Some then would even recommend one of his "BM" or "Big Mac" output transformers for each of the dual outputs, again giving the best floating balanced operation and optimal output impedance. Even if you make a good active splitter, it's still best to get tru balance and really good DC rejection via one of his input transformers, and you can get great performance by using one that doesnt have too much of a turns ratio. Jensen transformers aren't cheap, but their shields are excellent, low RF pickup, good isolation, etc. So it is neither cheap, nor simple.īetween the two, decisions about what's useful, and outside them things like power supplies (not trivial) while a good transformer, while not cheap, leaves you only wondering about the layout of the box. It ought to have somebody next to it, and a visual indicator of its status, unless it's remote controlled. Perhaps a bit less gain range than most console preamps, but any noise or distortion here, or lack of slew rate, or compromised frequency response, will be reflected to both of the outputs, and to the final results. Either way, the outputs must be protected against 48 volt phantom. If the following stages are guaranteed balanced it's fairly easy to do a balanced driver for each line on a twin op amp if it's a bit of an unknown, you need a servo balanced stage, taking up potential imperfections on the destination lines, which is quite a bit more difficult to build (particularly at minimum noise levels). The trouble is that with active electronics your best noise figure is with a certain amount of gain, so the circuit which is best for low-level signals distorts on really loud ones, while the optimum for screaming rock hisses on solo acoustic sets. For a mere two way I'd suggest a splitter transformer a few dBs of loss on each output, but a lot less to go wrong and no power supplies to get kicked out on stage, lighter and a lot cheaper… The flight case weighed as much as an amp rack. I had a twenty four channel rack of one input four out splitters (FoH PA, monitors, recording truck and TV truck) which had transformers everywhere, and still had to have pad switch, polarity invert and phantom power for each input, ground lift and pad for each output. Why active? Are you intending to have gain in there? And should the outputs be totally isolated (for example, splitting to an external recording console and a PA system)?
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