impedance matching--could you dumb it down 4 me?

with limited time to research the issue fully (as well as a very limited technical knowledge base to begin with), i'd appreciate it if some basic rules of thumb or forumlae could be explained regarding preamp-power amp matching. a few examples of my confusion: does the power amp input impedance always need to be higher than the output impedance of the preamp? or is there an inverse relationship (low ---> high, or high ---> low)? let the spoonfeeding begin. thanks in advance.
The general rule of thumb is that the input impedance of the amp should be at least 10X the output impedance (worst case) of the preamp.

You're trying to minimize the voltage drop across the output impedance of the preamp so that the voltage across the input of the amp is relatively stable throughout the audio band.
Absolutely not an expert here, hopefully someone more experienced will answer you... but I have the same issue and asked the same question...

I believe the general formula is at least 10 times, with some who think 30-40 times optimal... that is "input" impedance of your amp has to be that much greater than the "output" impedance of your preamp.

This was my link:

One goner mentioned a mismatch wasn't a deal breaker, only that you lose low and high end extension...and from my experience, probably microdynamics..

I just bought a tube preamp with a 3K output impedance and for the time being have it wired into the main of my budget integrated amp with a 20K input impedance....

and.. this may give me away as a total newbie.. but it sounds pretty good.. better than if I used the integrated's preamp. Of course, the tube preamp cost 3 times as much.

However, I do think I am missing a bit, especially with things like the decay, crispness of cymbals.. mostly higher frequency stuff. But it still works...

And like I said, not too experienced with this stuff....

If you're interested, you can go to this link, and read the Bound for Sound review of the M24, he uses various power SS and tube amps with the pre and gives an impression (one or two paragraph) of what various impedance matches had on the sound...

Hope this helps.
The relationship between impedance matching continues between the amplifier and the speakers as well and it's equally important to putting together a nice sounding system.

This really is a subject that anyone interested in high fidelity sound should make effort to understand before spending money on gear changes. Particularly purchases made without the aid of a dealer or experienced adviser. It's far more important when using vacuum tube products as this type of technology is more prone to having interaction problems with the associated components.
I've been learning--i hope--about impedence matching and have been studying Transformer Volume Controls. According to my source, a tvc's input impedence is dependent in part on its load. Does anyone know if this is true for other gain stages (TVC's can be made to have gain) ie preamps and amps? That is, does a preamp's input impedence depend partly on the amp's input impedence? Likewise does an amp's impedence depend on the efficiency of the speakers it is driving? or are these measurements static within frequency? Lynne