Blame the Nazis. They invented the tape recorder, and when the Allies seized some in the last days of the war, the face of recording was changed. Unfortunately, as we’ve discovered, tape decays and becomes unusable, and a lot of great music has to be dubbed from records, not masters, and unissued stuff is lost forever.

King Records of Cincinnati didn’t get a tape recorder until 1951, though, and even then they kept cutting some of their artists on the old metal-backed acetates, which they stored under excellent conditions. And that’s the back story to these, the first two albums of King and Deluxe acetates to be reissued.

The sound? Excellent, especially for the Delmore Brothers, who were basically acoustic with the occasional electric sideman. The duo had honed their act on radio and records in the 1930s, and by the late ’40s, their combination of hot picking and seamless singing was a decisive influence on the burgeoning “country boogie” movement, although they themselves recorded in many other styles.

These 1945-50 selections show the duo at the height of their powers; “Blues Stay Away From Me,” their biggest hit, is included in both a preliminary version and the finished one. Few of the other tracks here were hits, but that’s hardly any reflection on their quality. The interplay of their voices and Alton Delmore’s guitar and brother Rabon’s tenor guitar is fascinating throughout, whether they’re being sentimental (“Why Did You Leave Me, Dear”) or silly (“Barnyard Boogie”, with its piped-in sound effects).

And an interesting historical note: King president Syd Nathan recorded these sessions at E.T. Herzog’s studio, where Hank Williams recorded “Lovesick Blues”. If you’ve never heard the Delmores before, Ace’s Freight Train Boogie album has all of the biggest hits, and might be the place to start, but this is wonderful stuff.

The Roy Brown disc is less successful sonically and artistically, for a couple of reasons. First, the material is presented chronologically, which means there’s a lot of copycat material, given that the very first song here is Brown’s biggest hit, “Good Rockin’ Tonight”. (The acetate of the hit take has long since vanished, but the alternate used here is pretty good.) Second, these sessions were recorded at Cosimo Matassa’s J&M Studios in New Orleans in its very earliest days, and the room just wasn’t ready for the trumpet and sax that Brown’s band had. And third, although he had a nice crooning voice, Brown mostly recorded jump blues at this point, so the material gets repetitive pretty fast; the album is best enjoyed in small doses.

There’s also a reason that seventeen of the 24 tracks weren’t released; many of them aren’t Brown’s best work. Still, he was a better songwriter than a lot of his peers (although it was Wynonie Harris who wound up with the smash hit version of “Good Rockin’ Tonight”, and it was Harris’ arrangement that Elvis worked with in crafting his own). More than a couple of these tracks will show you why diligent parents, black and white, tried to keep their kids away from this awful dirty rhythm & blues stuff.

Ace has apparently bought all of King’s acetates, and is promising many more hillbilly, R&B and gospel releases from this trove. As someone who ranks King equally with Atlantic in the postwar indie-label pantheon, I can only applaud.