Rockabilly Guitar

A while ago I inherited a DeArmond X-135 from the estate of my dear friend (and phenomenal musician) Martin Smith, with whom I used to play in the Oxford-based rockabilly band, the Sugar Creek Trio. Martin was an exceptional drummer, but had also amassed a collection of various other instruments, including this guitar. I wanted to make sure that I could use this guitar out at gigs with my band, Jack and the Real Deals, but the single jazz pickup in the neck position meant that it wasn't really suited to the job.

This instructable shows how I turned this jazz guitar into a rockabilly machine, with the addition of a bridge pickup and some other bits and pieces. I hope you enjoy it!

Sorry for the lack of photos of this, but the first part of the job was to get the frets level - and the neck straight! This is not an expensive guitar, and it was clear that it could benefit a lot from a decent set-up. I'm sure there are plenty of instructables on here that show how to do a fret job, so I've just listed the basic steps below.

1.) Remove strings and place a straight edge on the neck
2.) Adjust the truss rod to get the neck straight (with no tension from strings)
3.) Mask up the fretboard and pickup, leaving the frets exposed
4.) Run a grinding stone over the frets to get them all level - it's worth noting here that I did mark out on the masking tape which regions were too high before doing this, to make sure I concentrated on the right areas
5.) When frets are all perfectly flat, use a fret profiling file to shape the crowns
6.) Polish the frets with Autosol or a similar metal polish
7.) Re-string to correct tension and adjust the truss rod to get the right relief in the neck
8.) Set string height and intonation by adjusting saddles

I should have noted as well that I replaced the stock fixed tailpiece with a Bigsby tremolo (from ebay), which was near enough a straight swap. I had to drill 3 new holes in the end of the guitar to hold the Bigsby in place but the strap button fitted in the original hole.

For the pickup, I wanted to get an authentic rockabilly sound, so looked on ebay for a Gretsch pickup. turns out there's a lot of choice out there, and prices seem very variable. I bid on a set of TV Jones pickups that eventually went for over £175, which was way outside my price range. After reading up on several review sites, I finally decided on an Entwistle 'Nashville' pickup, which is a direct replacement for the Gretsch 'filtertron' type. It's a humbucker with a coil tap - more about that later on. Simon at Entwistle was very helpful in providing me with a chrome pickup surround, which was vital in getting the pickup position marked on to the guitar.

I masked up the top of the guitar and sketched out where the pickup was going to go - this was made easier by using some string, tied to the strap button at the bottom and on to two tuners at the top, which gave a centreline to work from. I'm not 100% sure how well aligned the neck is to the body, but aligning the strings and pickups to the neck seemed a sensible way to go!

The photo shows the pickup position marked out on the top of the guitar, and also the position for the proposed pickup selector switch just below the cutaway.

This is the scary bit - drilling holes in the top of an archtop guitar is not for the faint-hearted :)

I know ideally that a router should be used for this, but my router was out on loan, and I was doing this job on my dining table so had limited facilities available to me! Drilling a series of holes with a sharp drill bit seemed a reasonable approach (photos 1 and 2), and did the job quite well. I then used a Dremel with a cutting bit to remove the wood in the centre of the hole (photo 3), and trimmed the edges with a small sanding bit in the Dremel (photo 4).

Once the hole had been drilled and the edges sanded, I offered up the pickup to make sure it would fit. I had to fettle a bit around the 'ears' of the hole to make sure that the height adjustment would be possible once it was properly mounted, but other than that everything was fine.

With two pickups, you need more controls! I had a couple of ideas regarding wiring options, but whatever I did I knew I would need 4 potentiometers and a pickup selector switch. The stock guitar had 2 pots and no selector, so out came the drill again. DeArmond / Guild make an X-155 which has 2 pickups. Thanks to the magic of google images, I got some photos of the 2 pickup model and tried to get the controls in pretty much the right places. I wanted the pickup selector on the lower bout rather than the upper one (where it was on my ES-295) to make it a bit more accessible during playing.

The last bit of drilling was for the 4 tiny holes in the pickup surround, which I did after stringing up the guitar and setting the bridge in roughly the right position. This was very important as the new pickup needed to be aligned with the neck, the original pickup, the bridge, and the new Bigsby tremolo!

Turns out I did a pretty good job of getting the main hole lined up right (phew!) so it was easy enough to drill the 4 holes with the strings still on the guitar.

I had to shim the Bigsby tailpiece using a washer on one edge (a bit of a bodge if I'm honest, but it did the job) to get the roller part to line up nicely with the bridge.

Point to note: I replaced the stock bridge with a roller type unit. Probably not all that necessary as the original mahogany bridge would have rocked enough on the mounts when the Bigsby was used, but having the roller bridge means that each saddle can be precisely adjusted so it should play in tune all the way up to the dusty end :)

I wanted to give myself a range of options as far as sound was concerned, so I had a little look online to see what could be done with humbuckers where there is a tap between the two coils. The original DeArmond pickup is a humbucking type with a coil tap, as is the new Entwistle pickup, so I decided to make use of the taps in both of these.

Rather than using a switch to turn the second coil off or on, I opted to use a potentiometer for each pickup as a 'blend' control, which would alter the amount of the second coil's signal that came through. I used 500k log pots, with a push-pull DPDT switch, as I also wanted to be able to choose which of the coils was 'on' and which was to be blended. The circuit diagram should hopefully shed some light on what I'm talking about here - the push-pull switches just swap the polarity of each pickup, and the potentiometers control how much resistance there is between the coil tap and ground. I used Schemit online to produce the diagram above - a lot more legible than my hand-drawn original!

Fully grounding the coil tap effectively makes the second coil of the humbucker redundant (the first coil -ve goes to ground), so you get a single coil sound. By adjusting the resistance of R3 and R4 (by turning the knob) an increasing amount of signal goes through the second coil before going to ground.

A point to note: after my first attempt at wiring there was clearly something wrong. It turned out that I had not connected a common ground wire to all components, so the circuit was open. By joining the grounds of all switches, pickups, and the tailpiece everything worked as it should.

And there we have it. I trimmed the scratchplate to fit around the new pickup, plugged the guitar in, and it sounded pretty good!

The output from the bridge pickup seems a little less than the neck pickup, which is a bit of a shame, but they are not a matched pair so it's not a big surprise. I will most probably get a neck pickup from Entwistle to match the bridge one at some point soon, though I tend to mainly use the bridge p/u anyway so I'm not that worried.

I am very pleased with the tone and response from the Entwistle pickup, especially as it wasn't very expensive (£25-ish). Next project will be to pop some better p/ups into my Stratocaster and then look at Alan Entwistle's inductive tone control...

Thanks for reading!

It sounded great - so I got the neck pickup to match :) Now all installed and heights adjusted to balance the volume of each, and it sounds truly amazing.