Cab arrived and all I can say is I don't know what I have. I've never seen a vintage Peavey 115 like this and the 6 digit serial on the back comes up with nothing on Peavey's serial lookup tool. I did confirm it has a Peavey Black Widow 1502-4. The cab measures 24"x24"x15".
Well, I guess it's a early to mid 70s era cab..? The serials were different during that era, stamped on that type of badge, many without any real reference to the year. IIRC, my bandmate's 76 Classic 2x12" has this same badge and I'm not sure how the serial is stamped. Is is just some random number and the speaker and transformer codes got us the year? I will verify this weekend.
I
think it was later in 76 or 77 when Peavey started using the larger, square badge with the 711 A St address and the ink printed characters; which included the model, serial (and later the manufacturing plant/building location). My earliest Peavey is a 77, and it has this type of badge. What's on your 78 2x15"?
Either way, perhaps you have an earlier version of the 1x15" bass cab? Since the BW and Scorpions didn't start surfacing until the
very late 70s, it
may have been reloaded and rebadged with the BW? The original speaker may have been a CTS square magnet speaker? The 1502-4 is the proper speaker for bass guitar, though, so if it was reloaded, it was reloaded right!
My 1x15" is from 1990, has the rough tolex with some grey speckles, top strap handle and black hardware. There are some other differences, which probably just occurred from changes in production or for the speaker. My internal volume calculation lines up with the Scorpion Plus Thiele spec.
Yours: 24wx24hx15d Slot port. BW 1502-4 speaker.
Mine: 24wx27hx13d Single 4" round port in lower left corner. Scorpion Plus SP-15425 speaker.