Need help with preamp selector switch for Condenser microphone

Hi guys,

I need to build a switch for my friend who work at a local radio station. Basically he needs to connect 1 condenser mic to a box that can switch to 2 different preamp strip from his mixer. Both preamp feeds 48v. What would be the best approach?
Thanks for your help

elskardio said:

Basically he needs to connect 1 condenser mic to a box that can switch to 2 different preamp strip from his mixer.

Click to expand...

Simplest way, use a wye connector to feed both inputs, and switch over by toggling both mute buttons simultaneously.

Gene

If your friend is feeding phantom the best option would be a mic splitter transformer.    Mic connects into the transformer. Main output  goes to one channel. Isolated outputs go to second channel. The main channel feeds phantom to the mic.  From there as gene suggested run both channels at the same time and hit mute buttons depending on which one is needed at the time....

Here is a schematic and data sheet for a jensen transformer jt-mb-d

http://www.jensen-transformers.com/wp-content/uploads/2014/08/jt-mb-d.pdf

pucho812 said:

If your friend is feeding phantom the best option would be a mic splitter transformer.    Mic connects into the transformer. Main output  goes to one channel. Isolated outputs go to second channel. The main channel feeds phantom to the mic.  From there as gene suggested run both channels at the same time and hit mute buttons depending on which one is needed at the time....

Click to expand...

Would it be possible to mute directly in the splitter box before the console's preamp? Use a DPDT switch to short pin 2 to pin 3 of the XLR?



*Edit: Looking at my drawing I see it won't work because the moment I short the Direct out, there will be no signal at the Iso Out. Maybe use 2 isolated output and feed the phantom power from an external power supply?

if you want to use a mechanical switch or relay you need one of those phantom power stand alone boxes for the mic. Make sure the phantom power box isolates the output from the 48V. It should. Then take the output of that to your switch. You should use a four pole switch so it also loads the unused preamp input with a 100 ohm resistor between pin 2and 3. Actually you could just short  pin 2 and 3 together. That will quiet the preamp thats not in use. Make sure the phantom power is off on the pre amps. You may still get a pop when switching.

elskardio said:

I need to build a switch for my friend who work at a local radio station. Basically he needs to connect 1 condenser mic to a box that can switch to 2 different preamp strip from his mixer. Both preamp feeds 48v. What would be the best approach?

Click to expand...

All the simple solutions will produce clicks or improper loading of the mic and preamps.
The best solution is remote control of the mixer's mutes; it may not be easily feasible though. An alternative is to mute via the insert points.