When you stumble upon a presumed-lost recording of Jerry Garcia and David Nelson playing bluegrass, you put it out – low fidelity, feedback and excessive crowd noise be damned.

That’s precisely what happened with Good Old Boys’ Live, a two-CD set recorded Feb. 21 and 22, 1975, and featuring the Grateful Dead’s Garcia on banjo and the New Riders of the Purple Sage’s Nelson on guitar joined by mandolinist Frank Wakefield, fiddler Brantley Kearns and bassist Pat Campbell. With the Dead on hiatus, Garcia had just produced the Good Old Boys’ debut LP, and when two of the members were unavailable to play live, Garcia and Kearns stepped in.

It makes for a great story and a so-so in-concert document that’s more worthwhile for its origins than the music in contains.

Live sounds like an audience bootleg, where the music competes with the crowd noise for aural space and the volume must be cranked. The bluegrass instruments feed back throughout the recording and one dude in the small audience whistles repeatedly and so distinctively, his friends could probably identify him all these years later.

There are some highlights scattered throughout the LP including Wakefield’s solo piece “Jesus Loves His Mandolin Player,” in which he imitates a harpsichord, and Kearns’ spotlight on “Orange Blossom Special,” which finds the small but raucous audience nearly drowning out the music. Garcia sings lead on “All the Good Times” and “Drink up and Go Home,” but he mostly a supporting player.

Fans of the Dead and the Jerry Garcia Acoustic Band will recognize tracks such as “Deep Elem Blues,” “Lonesome Road Blues” (aka “Going Down the Road Feeling Bad”) and “Here to Get My Baby out of Jail” and bluegrass aficionados may gravitate toward “Dim Lights, Thick Smoke” and “White House Blues.” But better versions of all these songs are easy to find and Live winds up being notable mostly for its gee-whiz, one-off nature and not for its ragged harmonies, too-loose musicality and poor sonic quality.