Building a Guitar from Scratch - The Goldnut Variation #1
Part one of a scratch-built Les Paul-style singlecut guitar.
I’ve been loitering around the MyLesPaul.com Luthier’s Corner for a while now, soaking up all that I can about building guitars. The many talented builders who contribute to MLP have inspired me with their builds, and given me the confidence to jump in and try to build my own LP-style guitar from scratch.
This being my first try, I decided not to go crazy with mahogany and a stunning maple top. Instead, I raided my garage and started pulling out walnut and rock maple lumber that’s been sitting, waiting for a suitable project, for many, many years. This will save both save me a big chunk of change and, by deciding to use walnut, let’s me break out of the traditional LP build mentality that it has to be a perfect replica of a ‘59 burst and try some subtle variations on the theme.
I’ve done some woodwork in the past, but nothing recent and certainly nothing this exacting. I have the typical hand-held power tools as well as a drill press and table saw but nothing more elaborate and may use a nearby rental workshop for some of the build. What I don’t have is a load of spare time, maybe a few hours a week but not much more, so don’t expect this build thread to go too quickly.
As for the name, “goldnut variation #1,” it’s a silly play on words - goldtop walnut and, hopefully, the first of many builds. With apologies to J.S. Bach, here we go:
This evening, I pulled out an 1.5” x 3.5” x 29” blank of rock maple and resawed it down to 1/2” strips for the neck. The center strip is walnut, resawn down to 1/2”. The outer walnut billets were ripped from a single piece of stock, leftover from another project.
I came pretty close, especially considering the fence on my table saw is only accurate to about a yard, so I want to run them through a planer and try to get everything as close as I can. I’m going to take my time on this one and do it right, even if it takes a while.
My new “Old Wood” ‘08 R9
After 14 years of waiting and looking, I’m now the proud owner of a Gibson Les Paul. A stunning 2008 1959 Reissue, to be precise.
I’ve wanted a Les Paul for years. I remember going around to different guitar stores and checking out the historics when they first came out around ‘94. (I still have the original Gibson Historic Collection brochure I got from Victor’s House of Music.) I was just out of grad school and there was no way I could afford one at the time. A couple years ago and I started playing again and could afford better gear so I started looking around but was discouraged by the limited choices I had locally and put off by the usurious asking prices. I wound up buying other equipment and telling myself I was happy.
But GAS for an R9 proved irresistible. About a year ago, I started trying to hunt down an LP that would get me close to “old wood.” The few times that I found a great guitar, it was snatched up before I could get my act together. When a MyLesPaul.com forum member listed this one on eBay, I jumped. In addition to the old wood top, he thoughtfully upgraded it with all the good stuff—Peter Florence Voodoo ‘59 pickups (amazing), Dr. Vintage ‘50s wiring, Vintage Clone ABR-1, RS Guitarworks tailpiece, Historic Makeovers inlays. This is a great guitar.
Maybe it’s just the honeymoon, but I don’t think I’ve even picked up another guitar more than once in the past two weeks.
My Old Yamaha Pacifica 1412 Lives!
I had this guitar for over a year with the best of intentions to fix it up, but never got around to it. There were always other guitars, different projects, so I traded it away toward a Yamaha Weddington Classic at the beginning of the year. In less than a month, the new owner cleaned it up, had a setup done, reinstalled the pickups and had the guitar back on the road. It looks great, he’s happy with it, and I’m happy with the Classic. Win-win all around. How cool is that?
JMP50 Clone Build, Part 10
A shakedown run with the new JMP50 clone. It lives!
After I finished the building and running through the basic tests I dragged my 2x12 cab and guitar down to the basement for a shakedown test. I started with the presence and tone controls at 5 and the channel volumes and MV at 0. Gradually increasing the MV and channel volumes, I was thrilled—and a little surprised—that everything worked the first time! The tone controls did what they were supposed to do, and the volumes worked correctly. Ramping up the MV and channel volumes, the 50W was getting loud… fast. I didn’t keep it cranked for long for the sake of marital harmony.
I did notice that in addition to what I expect is normal gain-stage noise, there was a fair bit of hum. Too much. Poking and prodding the leads going to V1-V3 didn’t seem to have any effect on the hum, so I began to think there was a problem with a ground point. Up to this point each cap can and the transformer each had their own ground point. The turret board and input jacks shared a common ground lug, drilled into the chassis between the volume pots and the input jacks (I noticed this on Greg Germino’s amps). I re-ran the input jack grounds over to the buss bar on the turret board, next to the volume grounds, and then took another lead off the buss bar from the presence end back to the same point the transformer is grounded. This helped a lot. There’s still some hum when I start to turn the amp past home playing volumes that I need to work on. I’ll probably take things apart again and ground each of the cap cans back to the same mounting point, creating a true star ground and see if that solves the problem.
Othewise, I’m still getting used to the overall sonic signature. Ch. 1 is a little brighter, and ch. 2 is a little muddier, than I would want individually. Combine them, however, and things start to sound pretty good. I would describe it as woody or stringly, but that doesn’t mean much. Higher gain than I was anticipating, but still relatively articulate. And I’m enjoying the “kerrang.” Even my wife noticed the difference and said she prefers the JMP50 over my last build, a Matchless DC30 clone.
What’s next? I just ordered a head case from Metro and will probably make some minor tweaks before I wrap it all up. I may try a .022uf coupling cap and different bright cap in ch.1, and some different values in ch.2 to see if I can tame ch.1 and make ch.2 a little more aggressive. I also want to swap out the 3A diodes for 1A fast recovery diodes and see how that sounds. I might replace the 10k bulk resisters in the power supply with Vishay/Dales just to be consistent. And, if I get really adventurous, I may try mounting the 5.6k swamp resistors on the turret board with leads down to V4 & V5, but I’m not sure how I would stake the turrets without taking the whole board out of the amp. Otherwise, there’s not much else I feel compelled to do other than get some playing time in.
JMP50 Clone Build, Part 9
Final setup and initial testing on my JMP50 clone
While the rest of the world—at least everyone in the US—was watching the Superbowl, I was finishing up my new JMP50 clone build. After the pictures were taken, I use a compressor to blow all the stray bits of solder and strands of wire out of the chassis and got ready to test per George’s instructions. There was a lot of junk in the chassis and I wanted to make sure I got it all out so some little piece of wire didn’t short something out when the amp was turned on.
Initial power-on revealed a big problem - no voltage anywhere. No heater voltage, no HT voltage. Nada. I had reversed the twisted leads that run from the on/standby switches to the HT fuse and mains voltage selector. Easy to fix and no harm done. A few minutes later, I had this corrected and began testing voltage.
Almost everything was within normal range for an amp without tubes installed. The exception was V1, which showed nearly 2x the correct voltage on one pin and no voltage across pin 3. This was because in my late-night building, I had forgot to add a jumper between two cathode resistor/cathode bypass cap turrets that are done differently on a typical 1987 build. Again, this was an easy fix once I figured out what was wrong. After that was sorted out, all the voltages were within their normal ranges. I began installing tubes and the voltages all stayed in their normal ranges. So far, so good. When I tried to bias the EL34s with a 47k bias resistor, I was only able to bring them up to about 28mA. A quick change from 47k down to 33k let me bias the tubes at 40mA, so that was good too.
So, how did it work??? How did it sound??? To be continued!