Scott Dorsey wrote:

Lorin David Schultz wrote:

"Typical" impedance for a line-level input is around 20K or so. A
device I'm looking at has combo Line/DI inputs. The switch changes
input sensitivity but not impedance. Thus the line inputs are balanced
+4, but with an input impedance of 10 Megohms. What are the
consequences of such a high input impedance (if any)?


High cost. And probably slightly higher noise due to some of the design
constraints involved in the super-high input Z.

agreed.

As long as the input Z is higher than or equal to the output Z, you are
fine,

Usually you want input Z to be at least 7 to 10 times output Z. Too
high an input Z is rarely a problem.

unless you have a device with an output transformer that needs to
see a particular load. In that case, a termination resistor across the
input is needed.