What is the Sound of Impedence Mismatch?

I've read that bass rolloff (happens due to interconnect capacitance) can be caused by such an impedance mismatch where the pre's output Z is too high for it's PA load, so you might have such an issue Drubin.
Have you experimented with different upgrade AC cords though?

No bass problems, actually, so that suggetsts no impedence mismatch. I need to experiment with cables and will also try power cords.

Wouldn't it be great to have a concise set of rules of thumb for system problems? Guidelines for identifying an impedence mistmatch, or cables with capacitance that is too high, too low, etc. Am I dreaming? It's just that it feels like most of the time I'm drifting around rudderless when some basic principles would help the navigation a bit.

While I'm at it, let me offer up my idea for the audiophile test CD I'd like to see. The Chesky Ultimate Demo disk is pretty good, but I'd like to see someone produce a disk that demonstrates the unwanted side of things. This is what grain sounds like. This is what midrange suckout sounds like. This is bad VTA ... azimuth mis-alignment. This is wooly bass. Clipping, even vs. odd-order harmonic distortion. You get the idea.... Even though the playback system would alter what you are hearing, I think you'd be able to get the picture if it is presented relative to a reference. Would be tremedously helpful to me in terms of calibrating my vocabulary with others.

-----Dan

Dan you are a dreamer indeed, but no fault with that! Your suggestions are really terrific. I think for now at least the closest that we'll get to "guidelines" are to be found here on these forums (try this - try that - see what happens - scratch your head some more). The funny thing is that a particular setup for one system may not be at all appropriate for a different one. (One person says that this XYZ cable is great, yet another person is totally dissapointed).
The "test disc" idea seems quite worthwhile; when are you going to get started? I'll buy the first one off the press..

I wouldn't know how to create such a disk, but I would put up some money to get it produced. Anyone interested?

As I thought about this, it occured to me that we might be able to capture noteworthy sonic signatures as well. Going out on a limb here, cause I know this is problematic and full of pitfalls ... if there were a way to convey the "classic" sound of CJ, of SET amps, selected eras from Krell, ARC, etc., the Koetsu sound vs. ??? Not a substitute for evaluating products, but it could have value in helping people who haven't heard it all (like me) to organize their preferences.

The impedance mismatch is only critical when the mismatch causes the preamp to go into distortion. If the preamp's current drain into a lower impedence device puts the preamp into a clipping mode similar to a amp driving low impedence speakers at high volume. So the sound is normal distortion IM and THD. Harsh sound would be the first clue. Some preamps can take a ratio of 1 and others need an amp impedence of 20 time their output impedence because they can't "drive" any current.