2. amps-preamps
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impedance matching amp/preamp

My amp is late 80's McIntosh 2250 solid state. My pre amp is a modified Ming Da... Impedance is way off, even though I think it has a very good sound. Amp input 50K the preamp outputs 100k which is totally backwards from all I read on the net. I have also used an AudioResearch preamp that was close in ohms, and my Onkyo AV receiver that also matches up with the amp. Neither sound as good as the Ming Da. My queston is how important is impedance matching and what am I missing.?
keslerd

Showing 2 responses by mapman

mapman's avatar
mapman
21,837 posts
 
I think I came across something like this before where 100K output impedance is the recommended input impedance for the amp to match the pre-amp's output. Not saying that is the case for certain in your case, but it is possible. 60K input impedance on the SS amp should match pretty well in general to most tube pre-amps I would say.
mapman's avatar
mapman
21,837 posts
 
Without getting into technical details, the analogy of how a drum skin works to produce sound is a good one to help understand what is going on.

A drumskin that is too loose will have less impedance to resist the strike of the drumstick which can result in a loose, distorted sound. Tightening the drumskin produces a tighter, less distorted sound. How tight the drumskin should be is a matter of taste, however there is some point at which too little tension produces poor sound quality

Eletrical impedance in a circuit is like the tension on a drumskin. it enables voltage fluctuations to register and be transferred correctly. If impedance is too low, the effect can become similar to that loose drum skin and result in higher distortion ie less accurate detection and transmission of the input signal.
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