A12 Input Impedance & J1-J2 questions

[markhan]

What is the input impedance of the A12?

How does installing J1 and J2 affect the input impedance? Would there be any problem with bringing these lines to a switch mounted on the back of the chassis?

I recently purchased a Peluso R14 ribbon mic. The salesman recommended an input impedance around 300 Ohms.

Thanks,

Mark

[tpryan]

What is the input impedance of the A12?

1200 ohms.

How does installing J1 and J2 affect the input impedance?

J1 and J2 will have no effect since the CMMI-8 that comes with the kit does not have a split primary.

Would there be any problem with bringing these lines to a switch mounted on the back of the chassis?

No, but it won't be useful unless you use a different input transformer.

I recently purchased a Peluso R14 ribbon mic. The salesman recommended an input impedance around 300 Ohms.

I suspect he's mistaken. Peluso's web site specifies an output impedance of 200 ohms for the R14, which would indicate an "ideal" input impedance of 2000 ohms or greater. I suspect loading the mic with 300 ohms would radically alter the frequency response.

[markhan]

Thanks.