Oh my, back to the tail end of the hazy days of the late 60's early 70's, but a good guess, without searching, would be either Eminence or C.T.S.
And I'd put more scheckles on a wrong than a correct guess, as those days are pretty foggy. I even did a small Wisconsin tour for a local Gibson dealer, with a Norlin Rep on keyboards, hawking those amps for a couple of weeks. Had a Gibson RD Artist and the Big LAB head with a cab stack for a rig. I did enjoy the sound in the context of an all LAB equipped band but my personal gigging rig, at the time, was an Acoustic 360 with two cabs and a Marshall 100 watt head head into an angled 4x12 being fed by a Rickenbacker 4005 and a Ric-O-Sound splitter so I never bought one despite the demo pricing we were offered at the end of the whirlwind state tour. Funny though as I remember having to learn the specs, etc., so I could spew forth to anyone remotely interested, but alas those memories are in a damaged sector today.
Cheers,
Mr. BEAR