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What is the Sound of Impedence Mismatch?

As I understand it, you want your power amplifier to have an input impendence much higher than the output impedence of your preamp, at least 10x. Can anyone tell me what the sonic symptoms are of a mismatch? If I'm hovering around 10x, what might I hear that would indicate an impedence mismatch as opposed to, say, a preamp that is simply too bright or whatever?
drubin
drubin OP
3,285 posts
 
Thank you, Bob. Great info! I think that making this kind of modification is beyond my comfort level, however. Would there be any way to fashion an interconnect "extension" that would add the resistance and let me see, on a diagnostic level, whether there is a significant change in the sound if I increase the impedence?
bob_bundus
1,834 posts
 
Two posssible approaches Dan...
A female-to-male add-on extension RCA connector set could be utilized with the series resistance incorporated therein. However just by adding the extension (even without any extra resistance built into it) you would likely change the sonic signature. I suppose that you could listen to the extensions first (without extra series resistance) in order to extablish a baseline, then add the resistors & listen again. But if you're not solder-savy then you would need someone to build this for you & then revise it later.

Another possibility would be to get some inexpensive (disposable)interconnects that allow the RCA connectors to be easily opened up, then add the resistance right inside the connector. Again, listen awhile without the extra resistance, then add it & listen again. Be sure to allow for cable breakin phenomenon too. However by using a cheapie cable, you're probably not going to realize optimum sonic performance either before or after; still you might be able to detect a change? But again if you're not solder-savy then you would need someone to do this for you.
drubin OP
3,285 posts
 
I think the second suggestion is a winner. I'm pretty sure I can handle the soldering, but--and I'm embarrassed to ask this--the resistance should be added to the "hot", right, and that is which, the inner plug or outer jacket on an interconnect? And, are resistors directional?

While I'm at it, I am also embarrassed to discover that I have been misspelling impedance all this time.
unsound
7,353 posts
 
Drubin, don't feel bad I misspelled the name of the item I have up for auction, twice! Then spelled the word in the manufacturers name correctly in the text. Talk about embarrassing.
bob_bundus
1,834 posts
 
Dan yes: the inner conductor. Direction of the resistor is not an issue.
Be aware however that the input sensitivity of the amp will be reduced somewhat, requiring a bit more drive level from the preamp source component.
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