Paul, yeah.. I was looking at the Behringer Ultra-Compact series of gear because, to be honest, I really like the form factor and it'd fit in well in my shack. However, looking at the output impedance specs of a lot of this gear, the impedance levels appear to be very low unless something is not registering with me.
JT, it probably helps that units like this typically use OpAmps, not transformers as output drivers, since the voltage source can ignore working into a higher impedance load by simply adjusting the gain and EQ to cover the impedance mismatch.
Quite different than trying to bolt up a low-Z microphone directly to a hi-Z mic input. The microphone coil, in that case, loads down the mic input stage, causing a low level of audio and a very bassy sound.
My experience is with a Collins 32V2. I am using a Rolls/Bellari monaural EQ/comp (HR11C) that has selectable line/mic input and output, with 1/4" TRS and XLR for unbalanced/balanced.
http://www.rolls.com/data/hr11cman.pdfThey quote the output impedance as 50 ohms, mic or line level (under
Installation).
In practice, I use an EV 635A driving the balanced mic input of the Rolls/Bellari, and I use the 1/4" TRS unbalanced mic output to drive the mic connector on the front of the Collins.
Very easy lash-up and sounds good.