T pad attenuator and phantom power

[wkbdgeorge]

What happens when a t pad style attenuator is between a mic and a mic pre that is putting out phantom to the mic?  Is it bad?  Will the world end? 

 

[shabtek]

its bad,what mic are you using? is it yours?
a t-pad is gonna throw off dc balance/cmrr.
is pad stepped switch or pots? either way noisy or pops when adjusted, mic may not like pops especially.
We usually see U(balanced l)  or perhaps H (balanced t) on mic pre ins

 

[wkbdgeorge]

its a switched t pad

 

[abbey road d enfer]

There's no good reason to use a T (or a H pad) pad between a mic and a preamp. The additional resistor(s) on the preamp side increases the source impedance for no reason. Just increases noise without any significant advantage.
As shabtek says "is gonna throw off dc balance/cmrr.", that's all. In particularly adverse situations (intense RF, temperamental preamp), it may impair audio quality, but generally would go unnoticed.

 

[emrr]

Phantom power will have differing series current limit R in each leg. 

Pretty much every vintage remote mixer with multiple inputs used a T or ladder on the input, so it was a standard.  50+ years ago.