RCA 77-D Impedance Wiring

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junomat
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RCA 77-D Impedance Wiring

Post by junomat » Thu Nov 07, 2013 11:09 am

Hey!

I just got an RCA 77-D mic from a friend. Actually for free. Was dumbfounded. But he wanted it to go to a good home.

The cable was clipped so I had to rewrire it.

My question is what output impedance do I wire it to?

I set it to 250 and I need to crank my pre all the way to get it loud. Is that the nature of the ribbon technology from the 60s? Would other impedances yield louder outputs?

Any insight would be great!

Thanks!

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digitaldrummer
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Post by digitaldrummer » Sun Nov 10, 2013 8:03 am

that sounds about right. depending on what you are recording, most passive ribbons may need 50-60dB of gain (and may still have levels below an active condenser mic).

oh, and congrats on the nice score!

Mike
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junomat
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Post by junomat » Sun Nov 10, 2013 12:46 pm

digitaldrummer wrote:that sounds about right. depending on what you are recording, most passive ribbons may need 50-60dB of gain (and may still have levels below an active condenser mic).

oh, and congrats on the nice score!

Mike
cool. thanks!

yeah, super stoked!

so would setting to a higher or lower impedance change the output?

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digitaldrummer
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Post by digitaldrummer » Mon Nov 11, 2013 4:40 pm

it might change the output some. Even condenser and dynamics may see slight changes from the input impedance setting. but what you may really notice is a difference in the low end response (which you also may perceive as gain - or attenuation - depending on the subject you are recording). again depends on both the mic and preamp though.

Mike
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emrr
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Post by emrr » Sun Dec 01, 2013 10:43 pm

If you are set 250, you are already at the highest gain. Try the others and see what you think of them. If you actually have tube preamps with 30-50 ohm input taps, they may mate wonderfully with a 77 set for 30-50.
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