attenuation pad

Hi there
I have a recording studio and i am using a stage box to take multiple
microphones into one multicore to pl;ug in to my mixer in a different
room.
Because i am using a relatively cheap mixer, it does not have any
attenuation pads. I was wondering what resistor sizes i would need to
use and how i would wire up a switchable 10db attenuation pad for each
of the mic inputs on my stage box. Also if i would like a LED to
indicate if there is an input signal would this be hard to add to
the circuit?
Cheers
Joe

 

[Gareth]

nottnick@googlemail.com wrote:

Hi there I have a recording studio and i am using a stage box to take
multiple microphones into one multicore to pl;ug in to my mixer in a
different room. Because i am using a relatively cheap mixer, it does
not have any attenuation pads. I was wondering what resistor sizes i
would need to use and how i would wire up a switchable 10db
attenuation pad for each of the mic inputs on my stage box.

There are lots of calculators on the web to help you work out what value
resistors you need, for example:

http://www.random-science-tools.com/electronics/PI_attenuator.html

You then probably want a DPDT switch (DPDT that's basically two switches
in one) so that one of the switch poles collects the microphone to
either the attenuator input or to a wire, the other pole of the switch
connects the mixing desk input to either the attenuator output or the
bypass wire.

o---------------------------------o
/ \
/ \
from mic>--o o-----> to mixer


o--------------R2---------------o
| |
R1 R3
| |
--------------------------------- GROUND

Also if i would like a LED to indicate if there is an input signal
would this be hard to add to the circuit?

--
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To reply to me directly:

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gareth.harris

 

Thanks alot gareth, just what i needed!
Any suggestions on the LED side of things??
Cheers
Joe