What do I need in this signal chain?

[Mark Seale]

In upcoming gigs I'll be playing both mandolin and fiddle. I've got condenser mics for both. My preference would be to run them into the same channel on my Acoustic Image amp which provides the required phantom power. Is there a 2 into 1 switch that passes phantom power? If that doesn't work, is there a lockout mute that I can put inline so I only have one instrument live at a time?

Thanks,

[almeriastrings]

Would not recommend this. Various issues with the phantom, and potential risk of damage to the mic. Much better: get a small, 2-channel mixer with channel mutes on each input. Use that as a sub-mixer. Unfortunately, from what I can see from a brief perusal of the specs, the Acoustic Image amps appear not to have a dedicated line-level input? Though you can almost certainly inject such a signal in the FX return loop input.

[Spruce]

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[Spruce]

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[almeriastrings]

Not useable with phantom powered condenser mics.

[Mark Seale]

I could run a small mixer into the FX loop, it would work fine. Are you saying the lockable mute could damage the mics? How so? What about something like this? http://www.radialeng.com/r2011/hotshotabi.php

rather than remove, just saw they don't recommend use with phantom powered mics.

[almeriastrings]

Hard switching of phantom powered mics is potentially damaging, yes, not just to the mic. Any switch (you'd need a DPDT) would also have to be near instantaneous and guarantee to switch both 'legs' of the +48v simultaneously, or you could, for a fraction of a second, have an unbalanced 48v hit your mics, and that's all it would take. Not good at all. There are several circuits for simply muting a phantom powered mic, and that is safe if done properly, but hard switching of two mics to one +48v source has a number of problems. You'd have to bring the channel gain down to zero anyway, or the loud 'Pop' each time could blow your speakers (and the audience would not appreciate it either). Much more elegant to use a small mixer. Both mics stay connected and you simply mute the channel (silently) of the one not in use. You'd also gain the advantage of two separate EQ options. One for each channel.

[mandroid]

Neutrik has a ring switch XLR Cable end .. that will mute the signal..

[Jim Nollman]

I have used the Neutrick XLR, but not with good results. I bought it to turn off my system signal whenever I was tuning my mandolin during a gig. It worked OK for a few months, but then the switch started to show a life of its own, turning on or off just from my movement on stage. I'm not sure if I just had a bad one, or whether the wiring is funky by default. I discarded it in favor of using the channel mute switch on the board.