EUB Project

[David Schwab]

I've added the perforated brass shells for shielding, and they also add a classy look.

I thought that might be shielding. I've been using very fine brass screening (like the kind you find in... ummmm water pipes, not that I'd know of such things).

I make my own bobbins by casting them out of polyurethane in silicone molds. The coils and shells are cast solid in black epoxy.

Cool! I'm going to start casting some stuff, probably covers.

Making parts is a pain. I just started having parts laser cut. Here's a prototype Jazz bass humbucker cut from 120+ old Bois D'Arc (osage orange). I painted it black. I haven't wound it yet.

[Bruce Johnson]

I've played around with different techniques, and I like the cast urethane method best. I can make up almost any complex shape that I can dream up, and it's quite fast and consistent. The urethane casting resin takes about 15 minutes to dry. I made up a whole row of duplicate silicone molds, so I can pour an entire "shipset" of bobbin parts in one shot. The urethane parts right out of the mold get a quick flattening on the backside and deburring. I drill the holes in the cast part, right into cast-in centering spots. Any machining operations are easy. The cast urethane is about like styrene plastic in model car kits.

The urethane casting resin naturally cures to an off-white color. You can tint it, as I do, but you can never get it to a real black. The darkest it will go to is the dark gray you see here, and the color can be patchy. So its use in external visible parts can be limited. But, these bobbins get sealed forever in black epoxy. I use Moser's powdered alcohol-based aniline stain in the Ebony Black color. The outer epoxy is West Systems 103/205, with the same powdered stain to make it black.

Here are a couple of quick pictures of the bobbins and assembly sequence of the M-pickups. I'm in the process of a major rewrite of my web site, and it will include several pages showing all of the details of how I make my pickups. It'll be online in a month or two.

You can see my built in terminal lug design. U-shaped loops of buss wire fit into molded pockets in the upper bobbin half. The magnet wire gets wrapped and soldered to one end, and the other end sticks out of the epoxy outer casting, where the lead wires can be soldered on later. I just never liked the flatwork and eyelets thing. The coil as you see it here next gets fully potted in a special thin epoxy, before it goes into the mold with the shell for the final black epoxy overcast. My construction may be overkill, but I want these pickups to last 100 years!

[scojack]

Strange Brew ...ce

Hiya Bruce,
This one is a prototype for myself really, but i have a buyer for another. Glad i tried it first though as there's already a good few design changes in mind already. Wouldnt be looking to sell much beyond that though, the garden shed couldnt cope with the increased output, unless i throw out the kids bikes

Thanks for the offer of those gorgeous pickups they really look the Dogs Bollox (Hope that translates ok). Ive already got most of the materials to have a crack at it myself though, so im going to at least give it a go first, that said...i might take you up on the offer yet, they could go on no2 very nicely.

Thanks for taking the time to reply Bruce, i've just been in your website and looking at all the cool stuff you do .... im surprised you had the time! If your ever looking for an assistant ......im yer man !

IanM

Ian;

Is this bass just something that you're building for yourself? Or are you developing it into an instrument to build and sell?

I may be able to help you with pickups, by selling you a modified set of the "M-pickup" group that I make for my own Scroll Basses. They're separate coils for each string, with three 1/4" Alnico5 magnets in each, arranged along the line of the string. They're powerful, and intended to give a thick rich tone with flatwound strings. I use them in a simple passive circuit. In this configuration, they're set up for a 4" radius fingerboard, which is what I use, but different bracketry could fit them to whatever radius you like.

You can reach me at brucejohnson100 at att dot net

[Seth Leigh]

Would pickups like these that Bruce has shown work with a bowed electric cello? I read somewhere that magnetic pickups can be hard to get sounding good with an electric cello or violin that is bowed. I'm asking because at some point (probably not as soon as I'd like) I intend to make an electric cello, and it would be interesting to make the pickups for it.

[Bruce Johnson]

Seth;

These pickups would work pretty well for an electric cello, because they're narrow and can be positioned up close to the strings at the tight fingerboard radius needed to get the bowing clearance. But they are magnetic pickups, so you'd have to use metal strings. And, yes, a magnetic pickup isn't really the best solution for a bowed instrument.

Getting a really good sound out of a bowed instrument is a different and more complicated problem than a guitar. One of my long time clients is Jon Wilson, who builds the Wilson GuitarViol, which is designed to be played with a bow. His standard electric model uses piezos in the bridge in a custom configuration, mixed with a radical magnetic pickup near the neck. He's spent a long time working with all kinds of pickup systems for that application, and we're working together on several new experimental systems now. We may offer them as kits eventually, but not at this time.

[Seth Leigh]

I have to wonder if getting a decent bowed cello sound would be as hard as getting a decent violin sound, using passive magnetic pickups, just because the cello sounds will be such lower frequencies, well under the frequencies where a lot of guitar pickups will have trouble with the highs.

Or is it because of the nature of the bowed sound, with the sound deriving from the bow microscopically "grabbing" and releasing the string a zillion times a second?

[David Schwab]

I have to wonder if getting a decent bowed cello sound would be as hard as getting a decent violin sound, using passive magnetic pickups, just because the cello sounds will be such lower frequencies, well under the frequencies where a lot of guitar pickups will have trouble with the highs.

Or is it because of the nature of the bowed sound, with the sound deriving from the bow microscopically "grabbing" and releasing the string a zillion times a second?

Bass pickups often get better highs than guitar pickups. But think about putting a magnetic pickup on an acoustic guitar. It doesn't really sound acoustic because you are hearing just the strings.

Ned Steinberger had to orient the piezos in two different directions, one for pizz and one for bowing.

POLAR PICKUPS: The NS Cello features the Polar bridge-mounted piezo pickup system. The Polar pickups can sense either vertical or lateral string vibration. Set in the vertical mode, plucked notes are remarkably even and sustained. In the lateral mode, the pickup has unparalleled sensitivity in the direction of the bow, with more attack when plucked. Attack and decay can be effectively controlled with the Polar pickup system.

As a player, you may not think about the direction your strings are vibrating, or even be aware that string vibrations on a musical instrument are polarized in relation to the fingerboard and the motion of the plectrum and bow. Yet direction is one of the most significant factors influencing the tone and response of a stringed instrument. In fact, instruments from the violin family are different from the lute or guitar in large part due to the effects of string polarization.

The bow drives the string back and forth in the direction of the bow, while at the same time it suppresses the up and down vibration. You can see this effect with the naked eye by watching the wide excursion of the lowest strings when bowed. From the front, you can see a wide lateral pattern of string vibration, but looking from the side you can see almost no pattern at all. Instruments in the violin family have a tall bridge in combination with an asymmetrical support structure of bass bar and sound post that efficiently translate the sideways motion of the bowed string into sound.

The Polar pickup responds with a high degree of lateral sensitivity and vertical rejection that is tailored to mirror the polarity of the bowed string. The result is a remarkably dynamic, rich tone that responds effortlessly to the bow.

The Polar pickup takes this concept one step further, and is able to switch from lateral to vertical sensitivity, which is ideal for pizzicato.

[Bruce Johnson]

The problem is the same in a violin and an upright bass. It's the way the string moves under the bow, and how that extra dimension of vibration is transmitted down through the acoustic structure. A magnetic pickup alone will capture the basic tone on the string, but it will be missing all of the other complex layers that make up the complete sound that you will hear from an acoustic violin. An electric guitar also has secondary effects from vibration and movement of the instrument's structure, but they're a subtle part of the overall tone. With a bowed instrument, the "secondary" effects are the dominant thing in shaping the tone. That's why it's so much harder to work with.

So, you can take the output from a magnetic pickup, run it through processors and amps, and have some fun with it. But you can't really duplicate the sound of an acoustic violin (or cello) just from that.

Our work is in the area of making some of the components mechanically vibrate to mimic the secondary effects, capturing that as a signal, and blending it into the overall tone in a realistic way. It's an ongoing effort. The mechanical percussive pickup that I developed for my Series IV Scroll Basses is a starting point. I hadn't intended it, but it actually works quite well as a bowed pickup. I'm continuing on from there.

[Seth Leigh]

This is some really interesting stuff. What I'm taking from this is that it really depends on how similar to the acoustic instrument one expects their electric instrument to sound.

If one is OK with their electric cello having it's own sound, like an electric guitar sounds different than an acoustic, then the magnetic pickups aren't so bad with the cello. It'll sound like an electric cello.

Thanks for your comments guys!

[nbtone]

The pickups on the yamaha cellos work very well. They are piezo pickups. I've been able to get a very realistic cello sound by using a tube preamp that I'm marketing. (Please forgive my spamming, but this is exciting) Here's the link: www.nitewalkerpreamp.com
I use both a bass amp and a guitar amp for louder performances, by feeding the high output to the guitar amp and the low output to the bass amp. It takes some digital effects to smooth everthing out, and I use gut strings. The end result is an real cello sound at a loud volume. Many of the amplified cellos that I've heard sound tinny and too electronic, and that's what I've been trying to get away from for years.

Would pickups like these that Bruce has shown work with a bowed electric cello? I read somewhere that magnetic pickups can be hard to get sounding good with an electric cello or violin that is bowed. I'm asking because at some point (probably not as soon as I'd like) I intend to make an electric cello, and it would be interesting to make the pickups for it.

[Bruce Johnson]

I haven't seen one of the Yamaha electric cellos up close, but the pickup setup is probably similar to what Jon Wilson is doing on his electic GuitarViols. There's a piezo element in each bridge saddle, but it isn't directly under the string, as it is in most guitar installations. It's angled off to the side, and it took him quite a bit of experimenting to find the right angle and position in relation to the string. A setup like that will capture a mixture of the lateral bowing vibration and the normal string ringing motion in some fixed proportion and phasing. It's pretty good, but still doesn't have all of the dynamics of a pure acoustic instrument.

The pure magnetic pickups like mine will sound much more like an electric guitar/bass.

[David King]

Anyone who thinks that amplifying a violin is a good idea must be deaf to start with.

[nbtone]

Probably someone who's tired of listening to himself, and wants to play in other people's ears at the same volume he plays in his own.

Anyone who thinks that amplifying a violin is a good idea must be deaf to start with.

[David Schwab]

Anyone who thinks that amplifying a violin is a good idea must be deaf to start with.

I played in a symphony orchestra when I was a teenager. Them damn violins are LOUD!

I guess if you are in a rock band you need it though.

[scojack]

Plan B

After David's advice i am now planning to use 6mm*25mm magnets.
but seeing as i will have 10 of the things im wondering if i shouldnt just use them up and do a coil (2*magnets) per string instead of a 2*split coil.
Obvious Questions comin up .....
How would i wire these up to hum cancel?
What kind of resistance would i be aiming at for each coil?
What polarity should each coil have?

Any Advice would be hugely appreciated.
IanM

EMG sells those single pickups to builders. Bill Bartolini also makes a set that works pretty well. There's the Pierre "String Charger" and last but not least you can get custom alumitones for upright bass and cello from Don Lace that match the curve of your fingerboard.

Location of the pickup determines the sound as much as anything in my experience. If you mount it at the end of the fingerboard it will sound an awful lot like a P bass. I like them about halfway back to the bridge or better yet make it movable.

Keep in mind that a longer (read taller) magnet will throw the field further up towards the string than a short mag and coil can and since the excursion on an upright string is enormous, you want a tall field with plenty of room. 1/4" or 3/8 dia x 1" alnicos would be a reasonable starting point.