Diaphragm-pickup from the old ampeg baby bass

[mafguitars]

diafragm pickup

Thanks very much, David, for digging up the pick-up. It seems to be a very rare, old microphone (Shure) special designed for transducing the double bass-sound, if i where you, i would not disamble it when it works !!!! (collectors value ?)
BTW thanks for intoducing Bruce Johnson to this thread, his story makes the difference to me, now i have an idea how the baby-bass-pickup works....
Regards, Marcel

[mafguitars]

Baby-bass

WOW, Thanks Bruce, this is some information to work with, either without pictures i can understand how this design works...
Some pictures would be great, but besides the fact that the availibillity of springsteel discs can be a problem around here, i might be capable to make my own version of it.
Did some resurch at <www.rayramires.com> but he does not give away the technical details, only a lot of pictures of the total instruments.
Thanks very much for sharing !!!
Marcel

[mafguitars]

Thanks for the numbers, Mr. jonson, i did some search at several databases, but i don't know where to find them, any suggestion ?
regards, Marcel

[Dave Kerr]

Marcel, go here:
http://www.google.com/patents
and plug in the number

[jonson]

patent

Maybe it would have been easier just to upload the patent so here you are MR Maf.

[mafguitars]

patents

Marcel, go here:
http://www.google.com/patents
and plug in the number

Thanks, I did find it in one hit ! Like Mr. Jonson asumed; 3244791
So now Im going to work it out and i'll let let you all know about the results,
can take some time, i have a full time job and have to built the baby-bass as well, but since i'm really enthousiastik, you never can tell.........
Regards, we keep in touch ! Marcel

[mafguitars]

Maybe it would have been easier just to upload the patent so here you are MR Maf.

Thanks again, You are a real help !
regards, Marcel

[Fast Freddie]

When guys like Bruce Johnson post a reply....wow! (I am not worthy).
Now all we need is Steven Azola to weigh in.

Here's my humble .02 cents worth:

The electronics are easy. Try making the two pickup bobbins:

http://www.stewmac.com/shopby/product/1462

http://magnetking.thomasnet.com/item...-1021?&seo=110

[mafguitars]

don't be so humble

Freddy, thanks a lot for your input, every thing i can get to know is worth a lot, doesn't matter how, and i am sure you are interested in this item, so what ? Thanks very much !!!
Regards, Marcel

[Luigi]

Hi, i'm not able to rewind my bobbins, does anyone knows who can sell me a pair for my handmade babybass? the whole pickup seems really like the old ampeg one, a low quality copy..
I live in Italy..

Thank you.

Luigi

[mafguitars]

Hi, i'm not able to rewind my bobbins, does anyone knows who can sell me a pair for my handmade babybass? the whole pickup seems really like the old ampeg one, a low quality copy..
I live in Italy..

Thank you.

Luigi

Hi, I might be able to rewind your coils, or make a new set of coils for your baby bass, cause its a handmade i have to know some more , please contact me at mafguitars@gmail.com

[Fast Freddie]

Hi, I might be able to rewind your coils, or make a new set of coils for your baby bass, cause its a handmade i have to know some more , please contact me at mafguitars@gmail.com

Although my OEM/ABB is functional, I've been working on a plan to assemble a BB designed by me. The only set-back I forsee are the two coil bobbins. I read years back that it was a lost art and that there were very few people that had the means to to make them. I searched high and low to see if anyone manufactured coil bobbins similiar to the ones used on the BB's electronics to no avail.

I thought to myself I should attempt to wind them up by fabricating something. I've not decided if too much time would be dedicated to just that for a one shot deal. But I may change my mind. What would you recommend?

[Bruce Johnson]

Freddy;

They're not difficult coils to make. It's not a lost art to us on this forum! Quite a few of us on here could make them, given the specs and dimensions. I make up similar coils for my own Scroll Bass line. I even have a couple of Ampeg Baby Bass coils sitting here on my desk right now. It's just a matter of who has the time to take on a one-off project. Making up a custom bobbin set and setting up to wind them takes some time. Are you willing to pay a couple hundred bucks for them? That's what I would have to charge you to make it worth my while.

Yes, you can make them yourself. But you'll have to build or buy some kind of coil winder, figure out a way to make up the bobbins, and learn some winding technique. Nothing insurmountable, but it will be an investment in time and money.

If you check out the other thread on Diaphragm-Type Pickups, you'll see our discussions on there about how these pickups work. You don't need to replicate the Baby Bass coils to make a good diaphragm pickup. You can work with many off-the-shelf pickup coil assemblies and get to the same result.

[Fast Freddie]

Hey thanks Bruce, (you da man!). My plans are still on the drawing board. I did'nt know you made them. But now I am happy! I've got a link!

The reason why I'd like to replicate the Ampeg coils is because it's in the sound. Here's a question I'd like to throw out there. My ABB is original but the internal electronics are fairly new, (Steven Azola made them for me during his days with Ampeg). I have noticed over the years that they sound very punchy. Still has the classic 'thud' sound but the original classic BB had a much more percussive sound, (it's kind of hard to explain).

I've played differant BB's over the years and I've determined that it's not the bridge, (when I had the aluminum bridge there was more sustain). The wood bridge helps a little but I'm beginnig to think that there is more to it.

I'm debating perhaps it's in the electronics. What do you think?

[Bruce Johnson]

Freddy;

As I mentioned up at the top of this thread, probably 95% of the tone of a percussive pickup (diaphragm pickup) comes from the mechanical stuff, not the electronics. Playing around with the details of the construction of the coils isn't going to change much of anything. The coils and magnets need to have enough "power" to provide adequate output levels, and they need to be adjusted correctly in relation to the diaphragms. But, beyond that, most of the things that you could change in the geometry or winding of the coils aren't going to have much effect.

Think of a percussive pickup as a drum with a microphone inside. The diaphragm is the drum head and the coil/magnet is the microphone. The strings are the sticks that make the hit. Changing brands or types of microphones will only make a tiny difference in the tone or percussiveness of the output signal. Changing the position of the mike inside the drum will have some effect. But the biggest factors are with the drum head itself: how tight it is, what diameter it is, and what material it's made out of. If you want to change the tone of a drum, work with the tension on the head, soften the edge of the rim, or add padding inside to dampen ring.

Changing the bridge will make some difference, because it's part of the mass that moves with the diaphragms. And, the wood will tend to dampen out some high end. Keeping with the drum analogy, switching from an aluminum bridge to a wood bridge is like switching from hard sticks to a softer beater, but you're still hitting the same drum.

So the qustion is, how do you change the "tension" of the drum head? Unfortunately, it isn't easy. It's all in the diaphragm; how thick it is, what metal it's made from, the effective diameter, and how it's supported from underneath. Little details in how the diaphragms are fitted and adjusted are what makes one Baby Bass sound different from another one.