Ampeg SB12 w/ NC cab?

emblymouse · #1 07-25-2011, 10:52 AM

I've got an SB-12, but my cabinet says NC. The speaker is centered with 2 vents, one on either side. I don't see this on any other SB12's. What does the NC stand for?

Vintage-Blue · #2 07-26-2011, 05:22 PM

Are you sure it is an SB12 and not a B12? If you have photos of the head they would be very helpful.

I'm pretty sure the cabinet you have there is a B12N cabinet. Does it have two lid latches or four? The B12N and the B15N are the exact same amplifier, they even share the same schematic. The only difference was that the B12N came with the 12" cabinet like yours and the B15N came with the 15" cabinet. The NC refers to the circuit revision of the amplifier so in this case this cabinet would have come with a B12NC/B15NC head. That also would date it to around 1963-64. If you really do have an actual SB12 head I don't think it is original to that cabinet. If I remember correctly though an SB12 amp would fit on a B12/B15 amplifier tray.

I suppose there is also a chance that Ampeg used the B12 cabinet on some of the earliest SB12s but this would be the first time I've seen that.

JimmyM · #3 07-26-2011, 11:31 PM

I know a dude in Nashville who would like that amp.

emblymouse · #4 07-27-2011, 09:59 AM

Thanks for the replies. It appears to be a regular SB12 head. Note the cab label SB12-NC.
So if NC refers to an amp design, this bottom is made for that amp? I've never seen one like it, but I've only been paying attention the past year or so since getting this amp. It's a little smaller than all the other SB12 cabs I've seen.

Ok, photo evidence-

JimmyM · #5 07-27-2011, 10:03 AM

Orphaned head paired with orphaned cab. The cab is actually a B-12N cab, and C is just a revision number for the head, which would have been a B-15NC head. Bet it sounds awesome, but definitely orphans mated.

emblymouse · #6 07-27-2011, 10:24 AM

It does sound awesome, I had this guy give it a once over- Dave Lancaster: Mad Scientist, Tube Amp Tech, Top Notch BBQ Griller. , and now it's got much more juice! It came with a guitar speaker in it, I replaced that with a Celestion neo 12 I had. I know, that is probably blasphemy

So is this cab what is considered a double baffle with the twin port slots? All the other SB12's I see have just the one. Is my cabinet an old design that was replaced by those?

beans-on-toast · #7 07-27-2011, 11:25 AM

The serial number on the cab indicates that it was the 646th amp made in March 1964. The plastic handle was short lived and, from what I've seen, unique to 63 and early 64. The NC stands for New B series (as opposed to the original plain old B series without the N, such as B15 vs B15N), revision C.

Note that the cab's tube chart tubes are different from the type of tubes on the schematic that came with the amp. This supports Jimmy's theory that the head and cab are orphaned. You can examine the date codes on the pots under the chassis to estimate when the SB-12 head was built.

Careful with the broken metal Ampeg logo on the cab. Those things are hard to fix.

Looks like it is in really nice shape.

emblymouse · #8 07-27-2011, 11:54 AM

Thanks, this is great to know. I'm thinking I'll need to join up in the Portaflex club now

JimmyM · #9 07-27-2011, 11:56 AM

Funny, I was thinking the same thing!