Sinking the current for LED's in MB SID v2

[ChinMuzik]

So I've been contemplating building a non-MB6582 midibox with 8 SIDS....but one thing I haven't found is how the current sinking is implemented for the LED's. 

I see it referenced in the wiki but does anybody have a detailed explanation how they've done it?

[latigid on]

The typical method is to use a button-LED matrix (BLM). You scan columns of switches (via diodes) using 74HC165 and drive columns of LED anodes using 74HC595. The cathodes of both are connected in rows to another 595, but normally transistors are added to improve current sinking. In this case, the chip has an inversion mask applied.

[ChinMuzik]

11 hours ago, latigid on said:

The typical method is to use a button-LED matrix (BLM). You scan columns of switches (via diodes) using 74HC165 and drive columns of LED anodes using 74HC595. The cathodes of both are connected in rows to another 595, but normally transistors are added to improve current sinking. In this case, the chip has an inversion mask applied.

Thanks Latigid..

That's actually what I was inquiring about. How the transistors are implemented in addition to the standard sinking in the matrix design (so that I have more flexibility with LED choice).

I am now thinking it may it easier for my level of skill to just use 20mA max LED's