Originally Posted by: kjproThanks much Chris, you've been a great help.[/quote]
You are welcome.
[QUOTE=kjpro]
One last question though, can I use them both over an A major?

You can play anything you want over any chord or key. Obviously, they will sound "weird" or "outside" or "slightly out of key" because they have notes that are both in (part of the A major scale) and out (not part of the A major scale).

A better way to frame the question is: is this the sound that I want in this part of my music (song, song part, etc.)?

In other words, only the composer/musician can decide what notes should go together in a piece of music. The determining factor is if it fits the intention of the composer/musician.

Otherwise, it's like starting to write a new song and the first thing you do is ask yoruself, "Should I start my new song in a minor or major key?" At this point it's wide open. It's not as if there is "no right or wrong answer". The problem is you don't have enough info.

In order to answer that question you have to specify your intention. Do you want it to sound happy or sad? Ah! Now we have some useful info, we are getting specific about what you want. Major scales are happy sounding; minor scales are sad sounding. See? After you start to focus your intentions about what kind of sound you are trying to achieve, then you can aim for the right answer; meaning the right tool to use, the right scale or notes.

The reason we have, study, learn & use such a wide variety of scales & chords is to have them all in our "tool kit", to be familiar with the unique sound of each note, scale, chord and how it sounds with, or against other ntoes. So, that when we want or need the specific sound of such & such a note, scale or chord, we can "pull it out of our tool box" when you need it.

Make sense? :)