I had a sweet old Ampeg in the shop for a quick visit. It's AEB-1 #657, from around March '67. The owner, John, bought it recently from a music store in Maine; he lives in Vermont. He shipped it all the way across the country to me to do a checkup and tuneup. There was hardly anything wrong with it.
It's a beautiful Ampeg, in really nice condition. All original, except for one thing I found inside. It even has the original LaBella strings on it, and they still sound pretty good. The paint is sort of chipped around the perimeter of the body, as to be expected. The pickguard and rear neck plate cover have hardly any scratches on them. It has the bridge cover and it still has the damper fingers with the original black foam tips. I haven't seen any of them in a long time.
A closet queen. It looks like it was played gently for a few years, and then packed away in a closet in the northeast for 40 years or so.
Not much wrong with it. The neck has some forward bow, no twist. More relief than I like, but not enough to recommend any repair work. The body has the usual seams opening up, and some warpage. The action was quite high. The tone capacitor had completely died.
Nothing wrong with the headstock. A few chips in the paint.
The pickguard is in perfect condition. Note that the paint job has minimal black edging. Most of the AEB-1's painted like this are in the lower serial numbers, 200's to 400's. But here's one in the mid 600's. Most of the mid to higher serial number ones have much more black around the edges.
And there's the back. Fiery red lacquer, light black around the F-holes, and hardly any black edging around the perimeter. That's all original.
Opening it up, here's the first thing that isn't original. Aluminum foil for shielding. I'm almost certain that wasn't put in at the factory. So someone has had this Ampeg apart to do that. Probably back in the '70's. Note also that it has the sheet steel angle, not the round can. The steel angle was mostly used on the first 200 or so instruments. I've seen the can starting on instruments in the 300's. So, it's curious why the steel angle is on #657.
There's the original Tone capacitor, a 0.1 mfd electrolytic. It's completely dead; the Tone control is like a Volume control. These capacitors typically died after 30 or 40 years. I don't think I've seen one over 50 years that's still working.
Here's my standard repair and upgrade, if you haven't seen it. I put in two modern polyester 0.1 mfd capacitors. One goes in place of the original Tone capacitor, from the right lug of the Volume control to the right lug of the Tone control. The second one goes across the Volume control, from the left lug to the right lug.
Adding that second capacitor significantly improves the sound of a Mystery pickup. I recommend it for all AEB-1's, AUB-1's and Devil Basses.
Here's what the Mystery pickup looks like opened up, with the diaphragm removed. That's the masonite ring and the coil assembly. Note the rough free-hand routing after the body was painted. And how one ear of the epoxy casting of the pickup coil is broken and repaired by drilling a new hole. I believe that was done at the factory. I've seen a few other AEB's with that same sloppy work.
The little silver wire at the upper right is the ground wire for the strings. It goes down into that hole and contacts the tailpiece bar.
The black rectangle to the left is a foam pad to keep the pickguard from buzzing on the body. That's from the factory.
This is an important part of the setup of a Mystery pickup. Put a 6" steel ruler across the masonite ring and look at the gap to the magnets. It needs to be about 1/16".
Here is one of the strange screws that attach the diaphragm. They are an old obsolete head style called Clutch Head. The driver opening on the head is a small hourglass shape. They were used in '40's and '50's radios and TV chassis usually covering high voltage parts. Where you didn't want unqualified people messing around. Who knows why Ampeg used them on the Mystery pickup? Maybe they didn't want owners taking them apart? They require a special driver called a "C-2". Kind of hard to find these days.
On many Ampegs which have been worked on, the Clutch Head screws have been replaced with Phillips or Slotted screws. But these are original, and I may have been the first person to have removed them since 1967.
Another routine maintenance item whenever you have an Ampeg apart is to spray a little squirt of Deoxit F5 into each of the pots, to clean and lube them. Just a tiny squirt. These pots weren't crackling, but I did it anyway.
Here's a quick way to test the Mystery pickup before putting all those pickguard screws in. Set a tuning fork on the Bakelite block, and it'll send a nice loud A out through the amp.
One other thing I did to it was add some neck heel shims. I make up aluminum shims like this that fit at the back of the heel, behind the two rear screws. It took 0.090" of shims to bring the action down to a nice working range. Yes, I know all about the Tilt Screw. I don't like using them. The aluminum shims make a more solid connection between the neck heel and the body.
Anyway, that's it. #657 now has its full beautiful sound, and a nice comfortable playing setup. And the 58 year old LaBellas still sound great. It's on its way back to John in Vermont, ready for another 50 years of beautiful bass tones.
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