How can I tune mas bass guitar to A=444hz with a KORG GA-40 ???

Contact Hartke directly to inquire.

Cpontact Vox (Korg USA) customer service at this link-

depends on where you are. You can try
Bass Guitars

Unfortunately, the manual on
http://www.korg.com/us/products/tuners/ga_40/

indicates that 12 string is not supported.

The owners manual can be downloaded at
http://i.korg.com/uploads/Support/GA40_EFG1_633661472559800000.pdf

The YouTube tutorial is at
https://www.youtube.com/watch?v=Of4CRajvq0E

with a 12 string, you can often tune the octave until the tuner sees the matching note. It won't see the correct string number, but an A note is an A note, whether or not it's an octave higher.

Hope that this helps.

Just use as if you are doing a 6 string ( instructions in the pack ) only play one string in each group at a time. The thinner string in a pair should be exactly one octave higher than the thicker string. Strings of the same thickness are in unison ( sound the same pitch )

The low in side jack has a lower vol. but should only be1/4 less than the high in jack on most amps, --try this,-- plug guitar in high in then take all the treble off and 1/2 mid. range bring up bass range and if you have equauzation bring down 26k 5k 10k about 2 notches or points. See if that give you better bass tone.

i use korgpa50sd i had some voices by default but once when i inserted my sd card into the arranger every voices got deleted and now everything is new...so can you please help me to get back the old voices?

Make sure you have adequate input level to the tuner... some guitars MAY have inadequate output to be recognized CONTINUALLY by the tuner.

two of the controls are volume, two are tone, (at least usually). the best way to use the controls is to try one at a time till you find the combination that pleases you most. I have been playing bass for 40 years and have 7 bass guitars, two with active pickups and two that acoustic electric

well i hope you've figured it out by now, it's a really cool looking tuner and i love it. but if you are still having problems...
the switch on the left side: OFF, ON, LMP (ON with a little light so you can see in the dark)
The number and letters you see across the top of the interface indicate which string it is tuning to. 6E is the low E string (the thickest one) and 1E is the high E string (the thin one on the bottom of the guitar), i've seen many people get confused when they've tuned those two.
You can leave the tuner in auto and it will pick up what string you are trying to tune. but if you are having problems getting the correct string or whatever the case is, you can switch to manual mode. click the only button on the tuner and the specific string will light up on the interface.
If you press and hold the button, the tuner will go into flat mode, tuning all the strings flat.
once you have the right string and you're tuning it in, you want the needle to be centered.
that's pretty much it. enjoy!