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Impedance Mismatch: A.I. M3A, Krell KSA100

I've read opposing views elsewhere on whether there is a sound degrading impedance mismatch between the Audible Illusions M3A preamp, with an output impedance of 1.2 K and the Krell KSA100 power amp, with an input impedance of 22 K.

Something tells me that there is a definitive answer out there.

I own a KSA100 and I'm considering the M3A for use with that amp.

Thanks in advance for any first hand experience or expert advice!
128x128nolanh
ahendler
416 posts
 
Based on the usual recommended 10/1 ratio this more than fills the requirement. Should be fine
romandoc
12 posts
 
Yeah, but it depends whether that 1.2K is over the entire audioband. If, say, below 100Hz preamp's output impedance gets higher (I believe Stereophile showed that to be the case for the Aesthetix preamp), then an amp with the input impedance of 22K may not be a good match.
My personal opinion to be taken with a grain of salt is that for an amp with the input impedance of less than 50K the best match in a tube preamp would be one that is transformer coupled. That keeps the output impedance low over the entire audioband and guarantees electrical compatibility.
sonnyyoung
22 posts
 
I have an Audio Horizons preamp matched witha KSA-100S. Match made in heaven.
gmuffley
132 posts
 
Romandoc is correct. The value of the output coupling cap in tube preamps can significantly increase the output impedance of a tube preamp in the bass frequencies as compared to the rated output impedance at 1 KHZ. The actual output impedance of the Modulus,is probably significantly higher than 1200 ohms at 20 HZ. I would also suggest that the optimal impedance ratio is better at 20:1 or 30:1.
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