I'm planning on using the PC10k/150 as a line-to-mic preamp and line-to-guitar amp interface and trying to wrap my head around all of the impedances involved. The signal path is: line input +/- to primaries -> secondaries to a switch between "guitar" and "microphone" outputs.

For the "mic" output:
Let's say the line output z is 1k. The output z looking into the secondaries would be 15 ohms, given the impedance ratio of 67:1 (8.2 squared:1). That's plenty low for a mic preamp, so no problem there. Now, if I want to make sure that the impedance looking into the primaries is high enough to bridge the line input, do I need to set the output impedance by terminating the secondaries with a 150 ohm resistor? Or will the load of the mic preamp simply be reflected across to the primaries (x67)?

For the "guitar" output:
To emulate the output impedance of a guitar pickup, I'd like to have a 20k series resistor on the guitar output. Since this will only be attached to one lead of the secondary, however, I'll need to prevent this from being reflected across to the primary. Will the terminating resistor I mentioned in the first part achieve this?

Thanks so much in advance for your help.

First, it is the reflection of the secondary into the primary that gives the impedance.

I am not sure, are you going from a microphone into a line level input or line level into a microphone level input? The same with the guitar? I ask because a transformer can not go from a microphone in to a line level input.

Thanks for your response. I didn't realize the impedance reflection was a "one way street." It will always be going from high voltage input to lower voltage output. (line to mic or guitar)

So I suppose my main question then is, would terminating the secondaries with a 150 ohm resistor prevent the input from being loaded by the 20k ouput resistor?

It should not load down the transformer. I would suggest though looking at our PCW series. They are a little bigger transformer.

Great, thanks Brian.