Seventh chords with/without the fifth?

[KiwiSqueezer]

Another question for the experts, I'm afraid...

I have an old accordion to rebuild. It has a standard 120 button Stradella bass machine, with four-note seventh chords. Apart from harmonic consequences, this causes buttons to drop, all over the place (exaggeration, but it's a bit disconcerting...), when a seventh button is pressed.

Is there any disadvantage from the removal of the fifth from seventh chords - as in modern boxes? There are two options for this: one is to remove the appropriate pegs from the pistons (I have the gear to do this 'properly'); the other is to bend the levers down from the pegs. The second seems crude, but it's potentially reversible. Suggestions?

 

[debra]

Removing the appropriate pegs is exactly what I did on an old "Bianco Freres" 37/80 bass accordion which otherwise could not simulate the missing row for diminished chords.

 

[oldbayan]

One of my boxes has register buttons to select 3-note or 4-note chords, I too find the 4-note seventh chords unpleasant!

 

[dak]

Removing the appropriate pegs is exactly what I did on an old "Bianco Freres" 37/80 bass accordion which otherwise could not simulate the missing row for diminished chords.

That would entail removing the root note from the seventh chords. @KiwiSqueezer instead will have to remove the fifth from the seventh chords on his 120 bass standard Stradella (I am assuming he has a separate row for the diminished chords) or the "this causes buttons to drop, all over the place" problem will still be there. I expect the process of removing the pegs will consume less time than the process of making pretty darn sure that you are removing the right peg for every button.

 

[debra]

That would entail removing the root note from the seventh chords. @KiwiSqueezer instead will have to remove the fifth from the seventh chords on his 120 bass standard Stradella (I am assuming he has a separate row for the diminished chords) or the "this causes buttons to drop, all over the place" problem will still be there. I expect the process of removing the pegs will consume less time than the process of making pretty darn sure that you are removing the right peg for every button.

You are right of course. It's removing the root note to get the 7th to double up as diminished for the next note (one fifth higher).