2. amps-preamps
  3. 151314-2744

power amp/pre amp input and output impedence question

Hello, im in the process of researching a new system, low and behold my limited knowledge has led me to try understanding the input and output impedences to better assemble my new system as to the power amp and preamp.

in all of my years as a Hometheater guy I've avoided such topic because with "most" HT gear it all works together just fine.......

Hear I am many years later "catching up" on terms I should know, I was gonna just google and read, but most of the time well versed members can get to the meat better than random google replies

Thank you KG

kgveteran

Showing 1 response by dhite71

dhite71
358 posts
 
Hello all,

When looking at my ARC component specs the ratio is well beyond 10:1

My Classic 120 mono block amp has an input impedance of 100,000 Ohms
My LS3B preamp has an output impedance of 500 Ohms

That ratio is 200:1

My next amp will be a REF 75, which has an input impedance of 300,000 Ohms.

That ratio matched with my LS3B will be 600:1

Am I doing my math wrong here?  This seems to be so well beyond the 10:1 target to not be of any concern.

Wondering about mixing brands, I checked a Conrad Johnson preamp.  Its output impedance was 100 Ohms that would drive that ratio even higher.

Next I went to McIntosh's website and the C2600 preamp doesn't list the output impedance.....only input at 44,000 Ohms, while my LS3B is 50,000 Ohms.

Are there some extreme examples of mixing brands where this is a concern, but most often not at all?

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