Something i came up with

i have also a chord progression of G-A-C-D and the song seems to be in A minor for the people who know what there talking about is that right?? Can i use the A minor penatonic for a solo with this song?

I can't comment on how catchy the riff is, as I'm at work and I don't carry a guitar with me, so I can't try it out. Also, I'm sure my co-workers would look at me strangely when I started playing guitar during work time ;)

Anyway, the notes you've used in this riff:

E----------------3------------------------3-----------------
B--------------------1-----3-----------------3--------------
G-----------------------2b-----------------------2----------
D-----------------------------------------------------------
A-----------------------------------------------------0h3p2-
E---3p2-------------------------3p2-------------------------
G F# G C A D G F# G D A A C B


For your information, that's in the key of G major.

As for your other song, if you have a chord progression G-A-C-D, then that's not A minor. In fact, the key is more likely to be G. In that case the A would be a borrowed chord (V of V). This gives you a I-II-IV-V chord progression, not uncommon in rock music.

Soloing in G major pentatonic gives you the notes G-A-B-D-E. The D note might clash with the C# when playing the A chord, the B note might clash with the C note when playing the C chord and the G note might clash with the F# when playing the D chord. So this is something to keep in mind when playing. It's OK to play these note during these chords, but if they are held for a longer time, not just as a passing note, then you will create a dissonance, which may or may not be desirable.

Personally, I prefer playing a melody that uses the pentatonic of the respective chord it is played under. So when the G chord is played, you pick notes from the G major pentatonic, when playing the A you pick notes from A major pentatonic, and so forth. Of course, this may be very tricky to do when playing live if you are not intimately familiar with the different scales, or when the chords change rapidly. Heck, I couldn't do it live myself, I just use it when composing tunes, but it does give nicer results.

wow thanks dude thats some great info i really appeciate it