On link#2 you can look at several keyboard layouts from all kind of melodeons. Most of the instruments have a diatonic scale on each row. I hope that's the right way to mention it. The Irish two row are chromatic ones(?), because they have rows like C#/D or B/C and there are also three rows which you can use as a chromatic one like B/C/C#. I think that playing this instruments is also different than playing a three row with A/D/G.
I stay with the one row, because increasing of the amount of buttons also makes it more difficult
Though the "Irish" 2 row 1/2 step boxes are chromatic and in theory you can play in all keys... they are played usually in D, G, A and their relative minors. Other 1/2 step systems are the D/D# and the C/C#.
The B/C/C# system was favored by the Scottish player Jimmy Shand. There was a very expensive Hohner Jimmy Shand model... highly prized.
The B/C/C# boxes have a Stradella (piano accordeon) style bass system.
Another hybrid is the C#/D/G to allow playing in the English D/G system and also the Irish C#/D system.
Variants are the C#/D/D#
Another older widely used system was the G/C/B system used by the French.
Often these had Stradella bass systems and were known as "mixte" accordeons.
I wouldn't consider an Irish B/C or B/C/C# as chromatic. I think they're still diatonic, though you can get the total chromatic scale by going across rows.
I think chromatic TENDS to mean that it has all the notes of the chromatic scale when pushing in the same direction, and that notes on the pull are the same note as on the push.
I also think this is somewhat of a grey area, but leans heaving to what I just recounted.
A piano accordion is chromatic. A 3 or 5 row chromatic is chromatic.
This all is very interesting and i didn't know anything about all those different systems. Am I right if I say that each row on a Irish have a diatonic scale, but together with the other row you have chromatic possibiities?
CBA or Chromatic Button accordeons are also known as Continental Chromatics.
They come in "B" systems or "C" systems. also known as B Griff or C Griff.
They are usually 4 row or 5 row.. I have seen 6 rows but these were the Russian versions known as BAYAN.
These are not diatonic.
If I were starting accordeon all over..I would start,and stay with a CBA.