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Question About Audio Research Preamp Specs

Hi,

I am trying to understand Audio Research terminology while looking at their product specs.

For example, for the LS28 OUTPUT IMPEDANCE, it reads "600 ohms Balanced, 300 ohms SE Main (2), 20K ohms minimum load and 2000pF maximum capacitance..."

What does the  "20K ohms minimum load" tell me?

I am running a McCormack DNA-500 and it has an input impedance of 10K Ohms. It would seem that the amp would be compatible with this preamp based on the 10X/15X minimum rule of thumb. 

My concern is that the AR spec is telling me use amps with input impedance of 20K ohms and the DNA would not work well.

Thanks for listening,

Dsper
dsper

Showing 1 response by monoogan

monoogan
55 posts
 
You're reading it right and your 10 to 15 x is generally accepted. The world will not stop rotating if you use a 10k load.

I think where this goes is that the preamp may not meet full specs if you feed it into a 10k load. Output voltage may be compromised, THD may be a little higher and low frequency rolloff may be earlier. It will probably be fine and not hurt the preamp but may not sound the same in your system as in another one.

The Sterophile reviews for most of the ARC preamps I've seen seem to recommend a minimum of 10K in the test section, biggest concern being low frequency roll off. I've been feeding ARC preamps into 15K for years and they all sounded fine (Ref 2, LS26, LS 25).
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