Resophonic? Resonator? Dobro…whateva! I did it!!!

Remember how in the India of the 80s, the craze among musicians was owning a ‘Casio’? Music shops stocked them as many prospective customers came asking for a ‘Casio’. What those people actually wanted was a ‘keyboard’ but since the Japanese electronics giant, Casio, was among the first to come out with the instrument, somehow, the brand name became its name.

Another example of the phenomenon is Xerox. You don’t get a document xeroxed, you get it photo-copied. Xerox was the company that produced the machine.

Much in the same vein is the Resophonic or Resonator guitar. (As far as I understand it) Dobro is the name of the company and the name of a particular guitar model it produced.

Here are some facts about Resophonic/Resonator/Dobro guitars and an interesting bit of history.

A resonator guitar or resophonic guitar is an acoustic guitar that produces sound by conducting string vibrations through the bridge to one or more spun/pressed metal cones (resonators), instead of to the guitar’s sounding board (top). Resonator guitars are particularly popular with bluegrass and blues musicians.

Resonator guitars are of two styles:

  1. Square-neck guitars played in lap steel guitar style
  2. Round-neck guitars played in conventional guitar style or steel guitar style

There are three main resonator designs:

  • The tri-cone, with three metal cones connected by a metal brace in which the saddle stands, designed by the first National company
  • The single-cone ‘biscuit’ (saddle) design of other National instruments
  • The single inverted-cone design (also known as a spider bridge) of Dobro brand instruments and instruments that copy the Dobro design

The name Dobro was derived from its inventors, the Dopyera Brothers (DoBro), back in the 1920s, a play on words derived from the ‘Do’ in Dopyera and ‘bro’ from Brothers, and a word which means ‘good’ in Slovak.

In 1925, John Dopyera, a Slovak immigrant to California, US, and an instrument repairman/inventor, invented a guitar with three aluminum cones known as resonators (similar to diaphragms inside a speaker) mounted beneath the bridge. This resonator guitar turned out to be much louder than the regular acoustic guitar. The tone of the guitar was rich and metallic.
In 1928, Dopyera and his brothers Rudy and Emil, as well as other investors, founded the National String Instrument Corporation to manufacture the new type of ‘resophonic’ guitar, which was sold mainly to musicians working in cinemas and jazz clubs in the USA. After several years, the three brothers left the corporation and started a new company, Dobro (the name they also gave to the instrument). Their slogan was: ‘Dobro means good in any language!’

And this long-winded preamble just to let you know that I recently worked on my first resonator guitar!!

This Ashton was the single inverted-cone design type (also known as a spider bridge). The owner, an accomplished musician and a professional one at that, wanted to replace the plastic nut with a bone one.

Also, there was an ugly break along the seam where the top met the side, near the end block: a result of the instrument falling and hitting the ground.

And then, there was general maintenance to be done, an extra-large dose of love to be given!

The cover of the spider-bridge and the tail piece (through which the strings were fed), which must have been shiny chrome a few years ago, were tarnished and dull, as were the tuning machines.

So, off they came.

And as I suspected, underneath the hood, there was more dust than there is sand in the Thar.

The last photograph gives you an idea about the saddle. A split saddle with space in between to adjust the screw holding the spider-bridge to the inverted, spun-aluminium cone. By tightening or loosening the screw, one can dramatically change the sound of an instrument.

Returning to the saddle, you will notice that its top has grooves cut into it for the strings to hold it down, for better sound energy transfer. This is the only type of steel string acoustic guitar which has grooves cut into it. No other type of steel-string, acoustic guitar needs to have notches to hold strings in.

But I was a bit surprised to find simple rosewood pieces as the saddle. Generally, in ‘proper’ instruments, each saddle piece has actually a maple base and an ebony cap.

The idea is that both of these hard woods put together, will better aid sound transfer.

Anyway, I removed the saddle, being careful to make a mark behind each, at which end it would be put in. Check, you may be able to make out the ‘B’ (bass) and the ‘T’ (treble)

and then began the process of cleaning the dust-caked innards of the instrument. First, the spider-bridge itself was unscrewed, taken off, cleaned and kept aside.

But I had problems removing the cone from its cavity and I had to take this awl to prise it out.

It is the cone which vibrates once the strings are plucked and the vibrating diaphragm-like cone is what produces sound – much like the diaphragm in a speaker.

Ideally, you want the cone to just sit on the ledge meant for that. However, its sides should not touch anywhere.

The fact that the cone was not coming out on its own and needed to be prised from its spot meant that when played, the cone would not have been vibrating freely, and thus, not giving the volume and sustain as it should.

So, the first thing I did was to sand the rim of the cavity such that the cone just fell into it. Also, it could easily drop out if need be.

What followed was a thorough cleaning of the cone, for any dust on either surface would act as a damper.

Then, I turned my attention to the nut and try as hard as I might, it would not budge. Finally, when I managed to knock it out, I wondered what was holding it so good. It was super-glue, as I had suspected!

Just cleaning the slot with this specialised carbide chisel took 30-40 minutes. First use a plastic, hollow piece for a nut and then use super-glue to hold it in place. Why, Ashton, why?

And then began work on cutting to size and refining the bone piece that would go in its place. Of course, all measurements were taken and the nut sized to those dimensions.

With the nut in place, I turned my attention to the fretboard, caked with grime and DNA. The fretwires too, were tarnished and dull.

It’s always a good idea to get into the very corners of the fretwires and dislodge any dirt, grime, etc that may be lodged there. And a little re-crowning of the fretwires never harmed anybody.

Then, it was the turn of the headstock and the hardware there. The tuning machines were snugged-up and then given a healthy dose of the ‘love potion’.

And they came out looking like this

Later, I turned my attention to the damage in the body. The binding and the side had pushed in, pushing the top out and up, and no matter how much pressure I tried to apply, the top refused to go in. Afraid of making the damage more severe, I let it be and proceeded to fill the ugly break with a paste of sawdust and wood glue. 

Very pretty, right?

Yeah! I know, it must turn ugly before things start to look better. Here is the finished job, with varnish covering the sawdust-wood glue filling.

Certainly not an invisible repair but it is no longer in the state where it’s eye-catching and blot on the looks of the guitar.

The cover of the spider-bridge and the tail piece had been buffed to a mirror finish and re-installed with new, shiny little screws. As I looked, the strap buttons became eyesores and so, I swapped these

for these

The position on the heel was marked, drilled and the new strap button installed.

Everything was put back together and the guitar was strung up.

I was happy with the way things turned out, but more importantly, the customer was more than happy. It is that much more satisfying when you are able to satisfy someone who understands music and instruments, and about the work undertaken to achieve a certain result.

There was however, one sore spot. Right on the heel of the guitar, it seemed as if either the joint was opening up, or, worse still, the wood had cracked. I could not get the thinnest blade into it but I could certainly feel a lip when I ran my finger over it.

I have asked the owner to watch it carefully and bring it back to me the day he sees a larger crack, or, if he feels that the action on the instrument has increased.







Amit Newton

An experienced guitar tech with over 10 years of experience working on acoustic Gibsons and Martins in the Gulf region. There is nothing that cannot be repaired; the only consideration is the price at which it comes. And yet, if there is sentiment attached, no price is too high! WhatsApp/Call me: 7080475556 email me:

2 thoughts to “Resophonic? Resonator? Dobro…whateva! I did it!!!”

  1. Thank you lucknow guitar garage❤️
    The guitar plays and feels better than i got it new off the store

    1. Glad to hear that, Charu!
      It is always a pleasure to work on the instrument of a person
      who knows his stuff and what he/she would want to see in the
      finished product.

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