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Originally Posted by robd2
Good info guys. What is the logic behind matching pre amp output impedance to an amps input impedance? Is it as long as one is higher than the other you are ok?
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In theory you would want as low of output impedance in the preamp as possible and as high in the amplifier input impedance as possible. In simplified terms: The amplifier sees the voltage coming out of the preamplifer and creates a larger version of the signal to feed to the speakers. The higher the ratio of output to input impedance, the more voltage can be delivered the amplifier (the amplifier is not interested in current from the preamplifer so don't confuse this with how amplifier/speakers interact.) In practice due to other issues to consider and without getting too technical we say at least a 1:10 to 1:20 ratio is considered good.