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wiring audio transformer into mic chain for radio mic jack input

mb91w126

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Jul 24, 2013
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so here's what we have

mic->preamp-->eq->fx->box->radio mic jack

box has 6 pin plug to radio, PTT, up/down switches and input from fx.

I picked up a audio xformer from radio shack has 2 wires on one side and 3 wires on the other.
2 wire side shows 1 ohm, 3 wire side shows Center Tap -> red wire 33 ohms and the same to blue wire.

So I need to wire the xformer into box.
I can take balanced from the fx into box or unbalanced.

question is which way do I face the xformer.
 

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If it is the transformer I think it is (8:1000 ohms) I wouldn't use it at all. The 8 ohms winding will not be a good match for either the radio or the box. If you are looking for isolation than try two of them back to back. Connect the windings that read 1 ohm together on each transformer and wire the 33 ohm side of one to the radio and the 33 ohm side of the other to the box. Grossly mismatched impedances at audio frequencies will affect the frequency response. Also remember that you are dealing with only a tiny audio level at that mic input and it will be extremely easy to overdrive the mic preamp stage in it.
 
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LOL I still can't get over them calling a simple transformer a "direct box". Years ago I was talking to a musician that kept telling me I needed a direct box to plug my broadcast gear into the sound system for a broadcast we were doing. Eventually I asked WTF was it exactly he was talking about. When he eventually found the right words to use to describe it I laughed at him. I said "Buddy, see this box made up here? It is loaded with Hammond 812 and 850 series transformers with active balanced or unbalanced inputs and outputs with each output isolated from each other to avoid noise feedback to the other outputs etc.blah blah.... so PLEASE don't tell ME I need something that you yourself have no idea what it is in the first place." Oh yeah, back then a DB25 was a serial port on a computer.
 

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