How to match preamp and power amp?

How to match them by looking at the preamp output impedance and the input impedance of the amp? Any magic numbers? I don't understand their relationship. Please help.

I need help so this topic is right for me I had m8s500 power amp I bought

The m8 preamp musical fidelity the sound is horrible didn't know it was going to sound that bad I thought that it was the right match what preamp should I buy for this m8s500 power amp



You have a MF pre controlling a MF PA and the system sounds horrible. Hmmm....MF claims the M8s is the perfect match for the M8s-700 monoblocks. I find it difficult to believe why it would not be equally as good with the M8s500. This is odd. Perhaps there is some spec that dictates it is a better match for the M8s-700 than the M8s-500 but I do not know what that would be. Certainly not one that would make it so incomaptible as to sound horrible. I would contact MF or the seller.