Ampeg DD-12 rejuvenation, AKA Baby Dinosaur rrrRRAARRrr!!!

Beauchene Implements · #1 04-20-2011, 05:45 PM

I have not owned a proper bass amp in a really long time. Since I've gotten into building basses over the last couple years, I've played either into headphone amps or line-in to Garage band. I haven't played in a band since 2000 so it hasn't really been a necessity...but anyway, I missed having an amp.

I like the fEARful design, and was seriously considering building a 12/6; I have the tools, the space, and sufficient $k1llz to pull it off. But I've got baby #2 on the way, and since the price of those Kappalites got crazy (like last week), I've decided to go a different route for now.

So found this crazy little cabinet at Daddy's Junky Music- an Ampeg DD-12.

It one 12" and a tweeter in the front...and a second 12" driver on the back of the cabinet, low-pass crossed over at 150hz. This little cab sounds badass in the mancave, even with only half of that little Genz Benz ML 200. (It's a 4 Ohm cab, so I can only use 100w of that head in un-bridged mode.) However, it is showing its age of almost 20 years: rips in the tolex, smashed edges with wood chunks poking out, corroded, hardware, broken casters... you know what I'm talking about.

So if I was still gigging, playing bars and backyard parties, I'd be down the condition of this cab and leave it the way it is. But since it's basically going to become furniture in my little basement happy place, I wanna make this thing look cool. So after a little searching on eBay, I found this for 20 bucks with shipping:

Green ostrich vinyl! Looks like dinosaur leather!

So this little cab is gonna get the baby dinosaur treatment. Next, I have to start finding new casters, corners, and feet.

JimmyM · #2 04-20-2011, 07:28 PM

ought to look pretty wild...keep us posted on the progress.

John Wentzien · #3 04-20-2011, 07:31 PM

Dean N · #4 04-20-2011, 07:45 PM

I just started my own cab refurb of a pretty beat Trace 210, so I'm psyched to see another one happening at the same time. I lurk at the LC, so I know you have all the skills needed to do a great job here. Hopefully I'll learn something. Subscribed!

logicman69 · #5 04-21-2011, 09:05 AM

I'm glad that cab went to a good home. I loved the sound of that little thing. I also like how you can change the tone a bit by positioning it differently in the room (up against a wall vs. in the middle). Can't wait to see it all dressed up.

tilehilder · #6 04-21-2011, 12:12 PM

I picked up one of these off of the Boston Craigslist a few months ago. Crazy little cab. Does yours still have the wattage information on it? The label on mine is worn off. I sent a PM to the Ampeg rep on talkbass and he asked around the office, but he could not find any info on it. I've been using my Genz Benz Shuttle 3.0 with it, but I feel like the cab could use additional power.

Beauchene Implements · #7 04-21-2011, 01:29 PM

Thanks everybody- I'll keep you posted on progress. I'm going to get all of my materials together before I start, so once I do, it'll probably only take a weekend.

dean- Start a thread! Recycling should be encouraged

logicman- great store, it was worth the hour-long car trip! My little boy enjoyed it too

tilehilder- I got the manual from tech support- it's the same manual as the SVR 212. The specs for the DD-12:

Impedance: 6 ohms nominal, 4 ohms minimum
RMS Power Handling: 400 watts
Maximum peak power: 800 watts
Frequency response: 70Hz-20kHz
Useable low frequency 40Hz
Low Frequency Limit 20Hz
Nominal Sensitivity 98dB 1w/1m
Maximum SPL 123dB
Transducer compliment 2-12" Special Design low frequency drivers
Bullet Horn Tweeter
Crossover points 150Hz (rear speaker), 4kHz (horn)
Crossover Slope 12dB/oct
Dimensions (HxWxD) 23.25"x21"x18.375"
Weight 90 lbs

I tried to attach the .pdf, it 225k so the forum won't let me (150k max.)

tilehilder · #8 04-21-2011, 01:34 PM

Thanks for the info. Can't wait to see ostrich vinyl.

Aram · #9 04-21-2011, 02:06 PM

I had the same cab many years ago and it RAWKS. Definitely agree with logicman69 on cab placement. Put that thing in a corner and you might as well be playing out of an SVT.

The ONLY bummer is the 90lbs + >18" depth makes it really awkward to carry. I think my brother still has my old cab in his basement...anyone know any lightweight drivers that I could retrofit to the DD12? This thread has inspired me to resurrect that thing.

Beauchene Implements · #10 04-21-2011, 04:14 PM

Quote:

Originally Posted by Aram

I had the same cab many years ago and it RAWKS. Definitely agree with logicman69 on cab placement. Put that thing in a corner and you might as well be playing out of an SVT.

The ONLY bummer is the 90lbs + >18" depth makes it really awkward to carry. I think my brother still has my old cab in his basement...anyone know any lightweight drivers that I could retrofit to the DD12? This thread has inspired me to resurrect that thing.

I was thinking that those Eminence Kappalites that go in the fEARful might be a cool upgrade someday, if the price comes down. Might be worth learning how to use one of the cab emulator programs, to see how it would respond.

And if you ever want to let that cab go, let me know. A stack of these things would be insane!

Aram · #11 04-22-2011, 08:03 AM

Quote:

Originally Posted by barnaclebeau

I was thinking that those Eminence Kappalites that go in the fEARful might be a cool upgrade someday, if the price comes down. Might be worth learning how to use one of the cab emulator programs, to see how it would respond.

If you (or anyone else) looks into this definitely let me know...if that cab could come down to 50-60lbs it'd be much, much easier to transport.

Quote:

Originally Posted by barnaclebeau

And if you ever want to let that cab go, let me know. A stack of these things would be insane!

I will do, but it probably won't go anywhere

Looking forward to seeing yours when you're done with the facelift though!

Dean N · #12 04-22-2011, 07:38 PM

Quote:

Originally Posted by barnaclebeau

dean- Start a thread! Recycling should be encouraged

I agree... here's my thread:

Trace Elliot 210 Cabinet Restoration

A demanding job and a rambunctious 18-month-old will pretty much guarantee slow progress though.

That's a heavy cab you got there! It'll look great in that vinyl.

Beauchene Implements · #13 04-22-2011, 08:10 PM

Quote:

Originally Posted by Dean N

I agree... here's my thread:

Trace Elliot 210 Cabinet Restoration

A demanding job and a rambunctious 18-month-old will pretty much guarantee slow progress though.

That's a heavy cab you got there! It'll look great in that vinyl.

I have a very boisterous 2.5 year old, and a new one on the way, I totally get it. Good luck! I'm looking forward to seeing how it turns out.

I was poking around in my cab, trying to figure out what hardware needs replacing:

Feet, casters, and caster cups gotta go. I found pretty close matches at reliablehardware.com. Their prices look good, but they have a 25 dollar minimum and the shipping is kind of high so I may keep looking.

I popped off the jack plate:

The crossover looks to be in good shape:

What's this about?

There is an automotive light bulb on the crossover, weird. Since this isn't an active cab, I don't expect that this needs to light up. I'm guessing it's for some tone-shaping function; resistance increases, the more power you put through an incandescent bulb. Maybe it's part of the hi-frequency attenuator circuit. Hmm.

Inside the cab:

I plan to make some precise measurements as I go, maybe try cloning this little guy in 1/2" baltic birch with some reinforcing stringers, and make a stack. TBD.

tilehilder · #14 04-22-2011, 08:37 PM

The light bulb protects the tweeter. Acme uses them on their speaker cabs.

logicman69 · #15 04-23-2011, 12:00 PM

Quote:

Originally Posted by tilehilder

The light bulb protects the tweeter. Acme uses them on their speaker cabs.

+1

We see these in Peavey cabs alot as well. Think of it like a big fuse. I think the idea was the lightbulb helps absorb some of the excess power that could harm the cab. At lease that was what I was told.

Beauchene Implements · #16 04-23-2011, 05:22 PM

Quote:

Originally Posted by tilehilder

The light bulb protects the tweeter. Acme uses them on their speaker cabs.

Quote:

Originally Posted by logicman69

+1

We see these in Peavey cabs alot as well. Think of it like a big fuse. I think the idea was the lightbulb helps absorb some of the excess power that could harm the cab. At lease that was what I was told.

That makes sense- it's like a slow-blow fuse, that can radiate some heat before it blows. Cool.

Beauchene Implements · #17 05-01-2011, 08:25 PM

I held off on doing any work until the TalkBass GTG this weekend in Rhode Island; incidentally, I never took it out of the car. There were more amps than people, it was an awesome event.

I ordered replacement corners, screws, casters and sockets from Reliable Hardware a few days ago. While I'm waiting for those to arrive, I got to tearing the cab down:

Those 12" drivers are beasts. At least 20 pounds a piece. This cab would be MUUCH easier to lug around with neo's, but I'm a little reluctant to throw down 300 bucks for the convenience. Not like I'm gigging or anything. They had a little mold on them though:

I gave them a wipedown with a cloth dampened with Chlorox Cleanup... and was met with the lovely, heady combination of old cigarettes and cat piss. Yay. I'll probably try to find some pet-odor neutralizer and go again before I put these back in.

Anyway, while I was removing the crossover I took some detailed notes-- I've learned to be dilligent about this, in my 30+ year history of taking my toys apart.

And here she is, stripped down:

Pretty rugged little cab, surprisingly light with those 12"s removed. Later this week I'll get out the heat gun and scrape off that tolex.

JimmyM · #18 05-01-2011, 10:51 PM

that looks like a car stereo sub! i'm sure it isn't

but it's pretty massive.

Beauchene Implements · #19 05-04-2011, 02:21 PM

Thought I was going to need a heat gun to remove the tolex... 20 year old glue is not so tenacious, it peeled right off.

Gotta find something better than this glorified toilet paper tube. Perhaps some similarly-dimensioned ABS pipe.

Now to dispose of some bad kitty pee pee-saturated rat fur.

All done, next up some sanding and crushed-edge repair!

Jerrold Tiers · #20 05-04-2011, 09:05 PM

Glad you folks like the DD cabs....

They were one of our wilder ideas, the plan being a cab that any sensible amount of power would be unable to "fart out". It generally worked, but they were "too weird" for most folks.

The crossover was so the higher frequencies would not be wasted shooting feedback creating sound backstage.

The lamps are not a fuse........ The filament changes resistance as it heats up. It's pretty much a short when cold, but if too much current goes through it, it heats up and resistance goes up to limit the current. Ideally it should NOT blow within the rating of the rest of the cab.