2. amps-preamps
  3. 1321758362

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
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.
stereo5's avatar
stereo5
6,279 posts
 
I have a Modulus 3A preamp coupled with a Stratos Extreme stereo amp with a 22K input impedence. It is a match made in heaven. I am smitten with the sound and couldn't ask for any better. I would suspect your Krell amp with the 22K input impedence would be a great match as well.

Bob
jcus
26 posts
 
Should be no problem providing you don't run very long, high capacitance interconnect cables. We know of many Krell owners who also own an M3A with excellent results. Regards, AI Technical
nolanh's avatar
nolanh OP
3 posts
 
Sonnyyoung: Later Krells tend to have much higher input impedance ratings. The KSA100S has 47K for instance.

Jcus: Could you provide more detail on length and capacitance you are referring to for interconnect cables?
grannyring's avatar
grannyring
6,441 posts
 
The output coupling cap value should be large enough as to not roll off the bass. Need to know the value of those caps to help you. If they are over 3.3uf or so you will be fine.
More to discover