I hate that people keep spreading the myth that you need an upright in bluegrass. It's not true and and it never was true.
Many of the 1st generation bluegrass bands used electric bass. Idk why this misconception keeps getting rehashed.
You don't need your electric to sound like an upright either. Get good tone out of your instrument and play well and it'll be fine. Just like any other genre
To what bands are your referring? 1st gen bluegrass bands formed prior to the availability of the mass produced electric bass guitar.
Uhh, Bill Monroe, anyone? Historically cited as the father of what became referred to as the Bluegrass genre, he started formulating the concept in the 30’s, but it was fully realized by the late 40’s. Still before the advent of the mass produced electric bass.Reno and smiley, Jim and Jesse, Osborne Brothers, Doyle Lawson, jimmy Martin, Scruggs, Larry Sparks.
There might be some debate on who's truly first gen but these are all classic artists. They may not have used electrics initially but we're all happy to adopt it pretty early on.