Hello Frances, caution when tuning the BB. The Hammond bass Melodion will tend to play a bit out of tune. This melodion required a lot of air control or it will give the impression of it being out of tune. You need to provide enough air to the melodion prior to depressing a key. If you press a key and push air in at the same time you will hear a little out of tune. Fill the melodion with air the. Press a key you will hear a difference. It took a while for me to learn how to control the pitch but wil a little practice of when to fill with air and when to press you can keep it in tune.
Monsters of Melodica
By he way I will be posting a new video this week where you can hear base Melodicas in all their glory