Dobro Pickups

[jason lollar]

when I hear a resonator guitar with a magnetic pickup alone it is still impossible to mistake it for a different instrument- it doesnt sound exactly the same but to me there is no doubt its a resonator.
Problem with alnico is the shorter the dimension the poles are oriented along the weaker it gets, 1/4" tall rods have hardly any magnetism. The Dearmond shown earlier has a little stronger pull than rods and the steel plate on the bottom helps too. Alot of those really low profile pickups use ceramic magnets which at 1/4" tall will have 500 gauss or so- similar to an alnico magnet 1/2" long.
I have a barcus berry dobro pickup on my desk right now- its two ceramic bars a little shorter than .25 and it has a coil wound around each without any bobbins then its encapsulated in casting resin. If youve ever made a pickup that way youll know how hard it is to get it placed just right in the mould so the face of the pickup is completely covered. The epoxy on the face of this pickup is paper thin!!! Actually about half the thickness of a piece of paper- thats crazy. No wonder they dont make these any more they must have had a huge regection rate. Its hard to hang the coil in the silicon mould half a sheet of paper above the face of the mould (let alone two bobbinless coils) then you have to pressurise it to collapse any air pockets- too fiddley for me- I have done that type of construction but its a big hassle to set up and clean up. if any part of the coil touches the face of the mould your screwed.
I pretty much quit making .25 tall pickups- results are only so so and it takes some special set ups to do bobbinless so shortest I make anymore is about 3/8"

[Mandopicker]

Hi Jason,

Point well taken and thus the reason for many a magnetic Dobro pickups being available on the market today. The statement of being close enough and unmistakeable speakes volumes about the concept and difficulty of capturing the sound of any acoustic instrument with a pickup, especially magnetic designs. There are certainly sacrifices to be made in order to achieve stage level volumes, and getting close enough is generally good enough for most.

After all, the reason the Dopyera Brothers invented the Dobro was to get greater sound projection by the use of a mechanical speaker in the form of an aluminum cone. Magnetic pickups were around at the time, just far more crude than the amazing designs of today. Jason's being at the top of the list of course.

My statements were not necessarily meant to cause a stir or to deter, but more to get the idea accross that perhaps there is a better way that is just beyond our grasp. I know this is the place to go for such an answer.

If you have ever heard a Dobro or Resophonic guitar played acoustically (clearly many of you have), you would definitely agree that it is the complex array of textures and tones that really makes the instrument unique and worth trying to capture. Most of it coming from the cone/spider bridge/string and body resonance interaction.

Form the many years I have been around these types of instruments, I would suggest that a "combination system" that utilizes a magnetic pickup with a piezo electric design attached to the cone or perhaps even a well placed condensor mic could do the trick. Of course other issues like feedback will be a potential hurdle, but not impossible to jump over.

Like I said before, challenges like this are what makes this stuff fun.

Then again, maybe I am hoping for something that isn't possible, or even necessary. Depends on the perspective of the player and the expectation of the listener.

Heck, when I shut my amps off, put down my telecaster and pickup my mandolin to play Bluegrass or traditional country, we often use a single mic and put the instruments right up to it...Flatt and Scruggs style. Our AT-4040 or the like gets every detail and adds to the stage dynamic, too.

So Terry, don't be worried, just take all of this with a grain of salt and consider what you are trying to achieve. As you have read there are many ways to do this with none being wrong, just different ways to translate the tone of the instrument.

Most importantly, have fun on the journey to finding it!

[Sweetfinger]

FWIW I subscribe to the "you'll never really get the whole sound of a resonator with any pickup system" philosophy, so in years past I have just stuck a Dearmond "hershey bar" pickup right over the three holes at the end of the fingerboard on Dobro style instruments. I have seen many other Dobros outfitted in the same way as well and that combination works pretty well. I've thought about all kinds of ways to get the "cone" sound that I don't think anyone else has ever tried- but haven't actually got around to actual experimentation.
The 'hershey' Dearmonds are very low output/clear sounding pickups which is one of the reasons they excel in this application. If one were to try and replicate this style of pickup on the cheap, you could use a ceramic magnet from a cheap-o Strat pickup like those in the Mexican standard pickups, or a wider flat one like you find on some Squiers or "Gifmen' which come in budget off-brand guitars. Basically, you could superglue the magnet to a chunk of brass sheet stock and a piece of styrene or ABS(pickguard material). The local car paint supply here sells really thin sheets of ABS for use as spray mask. Solder the start wire to the brass and wind away right onto the magnet - pretty much like the old Dearmonds.
If you were really adventurous, you could buy a set of ceramic magnets from Radio Shack- there are some that are about half length. You could do a split coil humbucker.
Mold the final product into black epoxy or cover it with a chopped down "no hole" plastic pickup cover. Rock.

[RedHouse]

I've posted this idea before but it might be applicable here. You can use 1/8"x1/8" neo rods and insert them in the holes of a humbucker keeper bar. Then wind with or without a bobbin. It works.

Interstingly simple idea, I'll have to try that.