I just mated a pass x-350 with my sonic frontiers line-3 and some tubes went bad within a day. Maybe its just coincidence, but its got me wondering about impedence matching. The balanced output impedence of the line-3 is 90 ohms and the balanced input impedence of the x-350 is 22k ohms. I guess my question is will improper impedence matching cause problems? and what are the parameters to go by?
Mismatching impedence can cause roll off of the frequency extremes and loss of some detail, but it will not cause electric problems nor the death of tubes in your preamp. TWL is correct - your impedence match is fine (think in terms of a 10 to 1 ratio minimum).
The broad guidelines, which do have exceptions, is that the input impedance of the receiving component should be a minimum of ten times the impedance of the sending component. At roughly 200+ times you are way good as Tom says. Look elsewhere.