I believe you are talking about the b-15s.

I was referring to the two generations of the b-15 cabinet type, the early ported reflex design and the later thiele design, which was introduced in 1968.

jess oliver wrote:"Make ours bigger, make ours more powerful." That’s what my old boss said when he saw my Oliver Powerflex Bassamp that I came out with after I left Ampeg. Although Hull had sold the company, the new owners kept him for a while. That’s how this amp, Model B15S was born. Hull had engineering redesign my B15N, making it bigger and like the Oliver P500, twice the power. The circuit and tube complement is like my B18N design, which I believe was discontinued at about the time they started making the B15S.

They were still in Linden, NJ at this time, I think around 1969, Ampeg had gone public so they had enough money to make improvements such as the three position rotary switch, Bass, Flat and Guitar, added to channel one, and an extra input added to channel two. Each of the two channels has a bright and a normal input. They kept my fail-safe way of protecting the output transformer by putting the amp on standby if the speaker is not connected .They went back to including a tilt back leg as on my early Portaflexes. They went back to polished chrome hardware, such as the corners, instead of nickel- plated. They went back to cups in the amp bottom to help register the rubber bumpers on the detachable dolly..Some of these things the early Ampeg “bean counters” had changed or eliminated back around 1965.

somebody on this board from chicago was selling a 2nd gen b-15n for a very low price, (not $75 you bragging jerk) but still significantly less. I suggest doing a search.

of course, I wasn't around when all these were being made, but this is what I've read (ampeg book and other internet research)...

the b-15 (and the a-15 as you mentioned) came out around 1960. they quickly redesigned the preamp and renamed it b-15n.

Over the years, they tweaked the preamp section a bit and changed the rectifier tube to a 5ar4. ampeg also made 2x15 cabs and some with an extension 1X15 cab.

all of these got varying designations on the theme of B-15n

e.g.
b-15nb
b-15nc




re: solid state, I believe the b-15s has a solid state rectifier, but everything else is tube. ampeg did make 100% solid state portaflexes. some with 2X15 cabs, etc. these were named bt-15.


I'll scan the section of the book and post it for you. However, I've read elsewhere that some of the information in the book is wrong.

for instance, I said before the thiele style was introduced in 1968, I've seen an extension cab with the thiele design, but with the 1967 style tolex, etc. I wonder if this is kind of like the skunkworks thing where they had leftover parts and just built them.

i don't know why they named the 12" version the sb-12. there is a b-12x and I think there's a b-12xr which has reverb and tremelo I believe.

yours looks to be pre-1967. ampeg did continue to make the sb-12 in the new style cabinet.

http://www.ggjaguar.com/sb-12.htm

I think you'll find that the 12" cab and the 15" cab are very different sounding.

You should definitely pick up that b-15n, but you should also consider getting a repro thiele cab made. it's a great cabinet and sounds very different than the earlier cabs.

http://www.ggjaguar.com/b-15n.htm

to my ears, the later b-15n cabinet sounded a lot louder and seemed to have a flatter response. still if someone was offering an earlier b-15n for $75 I wouldn't refuse it, even though I can't afford it, nor do I have room for it.


here's the scan of the book:

http://www.sendspace.com/file/r229ya

BadComrade wrote:The B-15S amps are ugly as fuck:

And I don't like the way it's lookin' at me, either. You gonna do something about that, or what?

BadComrade wrote:Yeah, but the later cabinet and head look like some weird piece of office equipment or something. I love the way my era amps look. Plus, I don't mind the sound being colored by the cabinet a little bit... it gives the amp a little more unique character. If I wanted something sterile with "flat response", I'd buy a fucking Eden or something

I was trying to be nice and not say it sounded mushy.

enjoy the pages. that book is kind of a disappointment. I would've preferred a real book, nice single page photos of the amps (inside and out), less boring story about the history of the company. the book is like 3/4 about the stupid founding owner of the company.

they should've put schematics and some technical analysis about the design of the amps.

BadComrade wrote:Maybe "Mushy Portaflex" will be a setting on a future Line 6 amp simulator.

yes, and when Line 6 comes out with it, you should buy it and sell your SB-12 to me for $75. That would be a good way to convince me.

My amp is the big, heavy boxy-looking thing that I plug my guitar into to make it louder.