Clinton -

Just for reference: Korg CA30

I can't think of a reason why the pickup and microphone should show a difference in pitch. One thing to check is that the "calibration" setting hasn't been changed. You can change the "base" pitch from the normal A = 440 Hz, it says, in 1 Hz increments, and when you turn it on it will "remember" the setting from the last time you used it - unless you reset it. Most other "low-cost" tuners come on at A = 440 and you have to change them each time if you want something different.

If your calibration "accidentally" got changed to A = 439 it would give approximately(?) the "error" you've indicated.

Not to state the obvious - if the microphone and pickup readings truly are different, it by no means is assured that the microphone reading is the "correct" one. Comparison with someone else's tuner(s) would give a quick-check.

The Korg site doesn't give a "tolerance" on the front page for this tuner - but similar ones generally are in the 2-cent to 5-cent "basic accuracy" range. Korg generally is about as good as any competing products in a given price range - and better than some, but these little guys aren't "laboratory standard" tools.

John