PCB design for guitar amps

[K O'Connor]

Hi Guys

How old-school am I? Or you?

I still use inches when laying the board even though every component you buy today has measurements in mm. When you make the library part, you can either convert the dimensions into inch and go from there, or lay the part out on a metric grid and let the board editor deal with it when you are laying traces.

I have hundreds of projects laid out on an inch grid and ponder changing to metric (as I really should do some time). The old projects are unaffected by doing new projects and parts in metric, until you go back to one of those projects and add a new part, or a new metric version of a part. The only issue will be whether Eagle thinks the pins are connected or not on the board, in which case you just make the grid small enough that it gets the trace centre as close as it needs for a "connection".