EBMM Preamp (in a Luke III)... voltage sensitivity?

[ruger9]

Just wondering, how sensitive is the preamp to voltage dropping from an aging 9V battery? Does the guitar stay the same until it dies, or does the preamp start getting distorted, or what?

On a whim, because I leave guitars plugged in alot, I just checked the 9V in my Luke III. It was down to 7.4V, I put in a fresh battery (reading 9.9V), and I don't think I hear any difference. Just wondering what to listen for to know the battery is tired...

 

[beej]

I think you'll hear it start running out of headroom- sounding distorted.

 

[Sweat]

First never leave it plugged in second what Beej said

 

[Rbg]

another question about the preamp. Do we know what is the output impedance? I see everyone say "low", but do we know exactly how low.

 

[beej]

Just guessing, but I would imagine it would be similar to any output buffer - well under 1k.