I'm very curious what the drum piezo will sound like under a banjo bridge

Me, too!
MIGHT need a built-in preamp.

I will post either a MP# or a video, right here on the HangOut.

Some folks think outside of the box. Mike, you have no box! I'm always intrigued by your innovations and can't wait to see/hear how it turns out!

Well, I once HAD a box, but I made an instrument out of it.

Buy the weigh:
I HAVE a built in preamp, off a ruined OVATION guitar.

I ran ONE string across a preliminary setup, taped some wires to a guitar cord, plugged it into a little amp.
Ta-WHANG!!!
No preamp needed.

Now to find the switch, and make a new recess for the pickup.

Sure is going quick!

Cool idea. I have similar kids first act guitar; but mine had a built in speaker about size of drum, and already has bridge PU; so I could just take speaker out and replace it with drum. It also has a built in on/off switch for built in speaker/amp.

For piezo, you won't necessarily need a preamp, often the preamp is more for impedance mismatch and tone. Many amps designed for Acoustic/electric have a high impedance input.

For a switch, might consider just replacing the vol pot with a push pull, should be easier to install.

Notice the neck had a slight bow.
So, dripped a bit of oil in there, rotated the nut to the LEFT, first, because IF it's rusted, it's not going to go right easily.
Moved without a problem, so I let the oil sit a few more minutes, cranked it right. Bow mostly gone, might hit it again, tomorrow, give the wood some time to get used to the new configuration.

Trimmed the pick guard.

Next step is to make a new recess for the old magnetic pickup.

So far, so good.

Nearby Mom & Pop store didn't have ANYTHING by way of switches.
Sadly, RADIO SHACK is no more.

Thought I might have to drive 40 or more miles to the American Science & Surplus store, where they got loads of stuff.
Would have cost about $6 for the gas.
But, the local auto parts store had a switch for about $7, throw it this way for ON for one device, the other way for ON for the other device.

The folks at the factory probably have a big ol' router, makes the recess for the pickup in a matter of SECONDS.
Using my cordless drill, half a dozen different bits, and a small chisel, it took me about 2 and a half HOURS!

And when I got ready to wire it up, I discovered that my soldering iron, although it lights up and gets warm, does NOT get warm enough to melt solder.
Going to grab a nap, then trek to the store and buy a new one.

Got a new soldering iron. Good to over 900 degF.
Wired everything together, plugged it into the amp.
The magnetic pickup AND the piezo both worked, according to which way the switch was thrown, but BUZZED like a gigantic bumblebeast!

Will re-try today, see if it's a problem with the cord, or if I've got the wires crossed somewhere.

And the project continues.

Did nothing much on the banjo Friday.
Saturday, made a new top nut from an old beef bone.
First, got a small piece of paper, cut as wide as the neck.
Then, measured the distance, on a banjo, between the edge of the neck and the first and last string ,to give me marks for the first and 5th.
Folded those two marks to give me the center, and divided the spaces between those marks and the center, to give me a mark for the 3rd & 4th strings.
Because I'm running the 5th string all the way up.

Will probably mess with the wiring Sunday afternoon.

quote:

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Originally posted by mike gregory

Got a new soldering iron. Good to over 900 degF.
Wired everything together, plugged it into the amp.
The magnetic pickup AND the piezo both worked, according to which way the switch was thrown, but BUZZED like a gigantic bumblebeast!

Will re-try today, see if it's a problem with the cord, or if I've got the wires crossed somewhere.

And the project continues.

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Sounds like you need to shield the pickup cavity and the control cavity, earthing the shielding. My electric upright bass had a big buzz, but lining the cavities with self adhesive copper tape with a connection to earth fixed that nicely. 

Thank ye kindly!

The original cavity had no lining, but aluminium foil is readily available.

ium foil is readily availab

HVAC foil tape works too. The adhesive acts as a slight resistor. I was pleased to see that even through the adhesive HVAC tape conducts fairly well.
That's a funky project. It looks like it deserves a cameo in a Foggy Mountain Spaceship video.

youtube.com/watch?v=hSowQCnApIQ&t=5s

Thanks for the link to banjos weirder than mine!

Soldered everything together, installed it IN the body, one string on for testing purposes, and it buzzed HORRIBLY.

Will try one more time, and MAYBE, if that doesn't work, Ill take out the magnetic pickup, since the drum worked OK.

quote:

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Originally posted by mike gregory

Thanks for the link to banjos weirder than mine!

Soldered everything together, installed it IN the body, one string on for testing purposes, and it buzzed HORRIBLY.

Will try one more time, and MAYBE, if that doesn't work, Ill take out the magnetic pickup, since the drum worked OK.

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Assuming you shielded all the cavities, have you connected all the shielding together and to the earth terminal of the output jack? If not, the shielding won't be doing its job.

I forgot to mention that you probably also need to earth the strings - a wire from one of the tailpiece screws to the output jack terminal (if the tailpiece is metal) should do that.

If all the shielding and earthing is fine, sounds like you have a dodgy componenet somewhere.

Today's the day I take the drum out, and paint its black face white, with KILZ primer. Just like re-frosting a Mylar banjo head.

Let it dry, put it back in, GROUND the strings, reconnect everything, and, once more into the breach (or the buzzing SON OF A BREACH)!

I am having trouble visualizing the design and circuit.
Here is one of my attempts at an electric banjo. All oF the piezo transducers I have tried are too hot to be attached directly to the head.

youtu.be/AD1703bW24g

Hey, Mr. McMurry!
Delightful sound from YOURS!.
I'll post a DRAWING of the circuit, since a photo would make a REAL electronics assembler throw up!

That looks similar to what I have tried, I use a pan pot rather than a double throw switch so the two sources can be blended. It is fun stuff to tinker with. I have not had great success getting tone that appeals to traditional banjo players. One thing that might cause a buzz is reverse polarity to the piezo.

Another cool project from Mr. Gregory!

I anticipate success.

I've only electrified a couple of banjos, and they really didn't keep much traditional banjo sound. I have one of the little mini electric guitars with a built in amp and earphone jack converted to a five string gitjo, but it sounds about as expected.

I once went all out and just stuck a piezo disk between a bridge leg and the head on a tin can banjo. I actually liked the results of that one.

Hey, Mr. 2o!
I like the sound of your tin can, too!

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I just puled the magnet pickup out, and am going to have JUST the piezo drum.

It was fun, but I'm sort of WEARY of fiddling around with the wires.

Playin'by ear is hilarious Mike Gregory, how did you com.e up with suuch a sily pictogram fur your pfp!!! ;)

Thanks for asking!

It was a farmers' market, and there they were!

I just bought one, handed my camera to a friendly person, and asked to have the picture taken.

I just happen to live on a very silly world.