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New build: The Electrocoustimatic 5120

Discussion in 'Technical Side of Things' started by Mr. Lumbergh, Jul 4, 2017.

  1. Mr. Lumbergh

    Mr. Lumbergh Gretschie

    432
    May 14, 2013
    Initech, Inc.
    Despite its quirks, I love my Gretsch 5120; it's moved back into the #1 spot and stayed there for about the last 8 months or so. I've been wanting to replace the stock Mudbucker pickups for a few years now; when clean they always seemed to lack a little sparkle and clarity, despite sounding pretty decent with some drive. As a mostly clean player though, that's a problem for me.
    I also enjoy playing this guitar as an acoustic and often practice unplugged to avoid bothering the neighbors when it's late. I figured that since it was a semi, it'd make a great platform to add an acoustic pickup to capture those types of tones. I like to be able to play acoustic rhythm and electric lead lines, and bounce back and forth between the two. And so about 6 months ago, I hatched a plan to turn my little Electromatic into the Electrocoustimatic to (hopefully) give me both. Starting with the pickups, I picked up a new TV Jones Supertron neck and a gently-used Classic Plus for the bridge back in February-ish. The coil of wire you see there is a few meters of a good, low-capacitance coax recommended to me by some of the good folks here. From Stewmac came the remainder of the electronics- caps, resistor, pots, LP-style jack plate to protect the body if I bump or step on the cable, and a stereo output jack. More on that later...
    The bridge and acoustic preamp were the last things to arrive about two weeks ago from Pro Audio Land, an LR Baggs T-Bridge TOM with piezo pickup elements, and a Control-X preamp to handle the two different sources. It allows either of the two or both to be output in mono or stereo and provides proper impedance matching for the piezo. I had wanted to mount this in the guitar, and had originally thought I could do a stealth install under the pickguard without drilling any new holes in the body, but as small as it is (it's designed to go under a Strat guard), there's just not enough room. A study of the installation destructions for the preamp and what came with the bridge for a dual-bucker LP style guitar (again, preamp is for a Strat but is the only one like it they make) makes me confident that wiring the TVJ's to the tip of a stereo jack and the Baggs to the sleeve will allow me to handle the preamp and mixing externally. The Control-X will instead go into a belt clip enclosure, many of which are available with 9V battery compartment. If I go plug in without the preamp, it should behave as any other upgraded Gretsch 5120.
    The guitar is not completely u̶n̶m̶o̶l̶e̶s̶t̶e̶d̶ unmodded, however; I did put on a set of Sperzel locking tuners shortly after I got it in 2011. The tuner shafts needed slightly larger holes, and I stupidly tried using a drill rather than reaming them slowly back when I didn't know any better, with predictable results to the finish; there are cracks around the tuners that I plan to fix with some drop fills while I have everything apart. There are also a couple of minor workmanship details in the mounting of the Bigs that I want to clean up. So, there is a lot to do, but not tonight... Time for steak, then fireworks. Stay tuned.
    Here are the goodies:
    IMG_0001.JPG
     
    Last edited: Jul 5, 2017
  2. MTurner

    MTurner Friend of Fred

    Age:
    61
    Aug 17, 2010
    Clayton, North Carolina, USA
    This is gonna be cool!
     
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  3. Mr. Lumbergh

    Mr. Lumbergh Gretschie

    432
    May 14, 2013
    Initech, Inc.
    Yeah, as long as I don't screw up too badly I reckon it will be. :D
     
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  5. ZackyDog

    ZackyDog Country Gent

    Feb 6, 2015
    In the USA
    Good luck. Check out these videos:

     
  6. Ricochet

    Ricochet Gretschified

    Nov 13, 2009
    Monkey Island
    Love the concept. Good luck.
     
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  7. thunder58

    thunder58 Gretschified

    Age:
    58
    Dec 23, 2010
    tappan ny
    HURRAAAAAAAY ..... a jackplate ( you know my pet-peeve gang , every guitar should have one straight out of the factory ) Good luck , sounds like a great project
     
  8. loudnlousy

    loudnlousy Country Gent

    Age:
    51
    Oct 18, 2015
    Hildesheim, Germany
    Good luck with your project.
     
  9. JC higgy

    JC higgy Friend of Fred

    Age:
    46
    Jun 6, 2008
    Belfast Norn Iron
    Looking forward to hearing the sound clips Mr.L !
     
  10. drmilktruck

    drmilktruck Friend of Fred

    May 17, 2009
    Plymouth, MN
    I've done similar projects in the past with a Nightbird and a 6120. It worked out well for the 6120. Nice array of sound options. The pain is figuring out how to accommodate the preamp & battery. In the 6120, I put them in a cloth bag that was stapled to the inside. To get to it you had to remove the bridge pickup. If it was a guitar with a backed, it could be done through the back.
     
  11. Mr. Lumbergh

    Mr. Lumbergh Gretschie

    432
    May 14, 2013
    Initech, Inc.
    Progress report for July 5.
    At the urging of y'all, I ordered the Reverend soft-spring. As I understand it, it provides longer travel of the arm, but a softer action? Sounds good to me; the throw is a bit stiff and the arm is low. We'll see how it goes, but I figure the best time is when I have it off the guitar already anyways.
    I stopped by my friendly neighborhood craft store this evening, Electro in hand, and picked out a tangerine-colored dye as well as the smallest dowels they carry. I'm going to try to match that beautiful orange on the back of the headstock as closely as possible and fill the holes left by removing the original tuners. The dowels came in a pack of 230 and I need 12, so I figure I have some room to experiment with the right dilution to get the color right.
    Here's today's haul. No disassembly yet; she'll being going with me to the lesson tomorrow since she'll be out of commission for the next couple weeks, I'd like to get some more time in.
    IMG_0001.JPG
    We love pics, so here's one of the intended ̶v̶i̶c̶t̶i̶m̶ recipient:
    IMG_0006.JPG
     
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  12. Henry

    Henry Friend of Fred

    Apr 9, 2014
    Petaluma
    Actually it provides less travel, as it is a softer spring and therefore compresses more so the arm rests lower. I asked reverend if they could provide a longer spring and they said no.

    My 2 cents is to literally use 2 cents - I have 2 pennies under the spring.
     
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  13. wildeman

    wildeman Friend of Fred

    May 10, 2015
    norcal
    Looks strangely familiar;) 20160220_095243.jpg And its current state. 20170704_162603.jpg
     
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  14. Mr. Lumbergh

    Mr. Lumbergh Gretschie

    432
    May 14, 2013
    Initech, Inc.
    Today was the day to start tearing her down, but not before getting about an hour of play time in on her. This post will contain good as well as bad news...

    Before getting started, I wanted to point out some of the small workmanship details that I planned on cleaning up while I was in the middle of the build. I don't know if you can see it, but the bridge doesn't quite match the curve of the top; here are some closeups of the end of the bridge and the section more towards the center. As you can see, there are obvious gaps; in the center it's enough that I can get a business card under the edge of it. I've got a plan hatched to clean that up and take it all the way to the top to maximize the contact area, but more on that later.
    [​IMG] [​IMG]
    This is another thing that always bugged me once I noticed it. The guy that was mounting the hardware did things a bit slapdash on this, but it will be fixed. The strap button also plays a key part of holding the Bigs in place, and I noticed during disassembly that the button receiver (best name I can come up with considering the way they work on a Gretsch) was turning in the wood. Since I've been having to tighten it up nearly every time I put the guitar on, it was a good catch. I'll be reinforcing the hole in the wood.
    [​IMG]
    Before starting the teardown, I made a quick check of the intonation and found that it was pretty close. It'll need some minor tweaks when it all goes back together, but for now, it's worth marking out to save myself some time trying to hunt for it later:
    [​IMG] [​IMG]
    Now for some of the bad. :(
    I had intended this thread to be a full-disclosure sort of deal, however the build turns out, and now it's confession time. Remember when I said that I was in a hurry and inexperienced while installing the locking tuners after I got the guitar? Yeah, I have to say I'm extremely embarrassed by these next two photos:
    [​IMG] [​IMG]
    I didn't even snap a pic of the worst one, it was just a bit too much. I had forgotten how bad these were because the tuners cover most of the damage, and indeed, at a quick glance you can't tell from the front. But I've always taken pride in craftsmanship, and there's no way to mince words about this one: it's a piss-poor hack job. I'm mad at myself after seeing it exposed again, hopefully I can restore at least some of it. The hole closest to the tuner shaft hole is the index for the Sperzel; the outer two are the screw holes for the original tuner. They'll be getting filled as part of the other work.
    I did a test fit of the LR Baggs bridge to make sure everything was good before I rendered it non-refundable, and it fits the Gretsch rosewood base:
    [​IMG]
    It did highlight another workmanship error though, and one that I don't think I'll be able to correct. One of the pins that hold the TOM section of the bridge is slightly off from being at a right angle. It wasn't an issue with the stock TOM section; it was loose enough to compensate. I could see it if I looked closely, but it never prevented me from being able to make adjustments when setting it up. The Baggs bridge, however, is made to much tighter tolerances, and it's made that error more noticeable. The bridge is a tight fit, and some finesse will be needed to properly set the height after getting it together. It's a quality piece though, I'm impressed with the workmanship. I'm pondering shrink-wrapping the braided leads, but I think they look kinda cool. What do you think folks, should I wrap them in black or get some clear heatshrink and show it off? Not much will be visible, I'll be notching one of the riser rings under the Classic Plus to get them into the inside, but I think it could look cool to see them.
    Here are the parts, bagged up for safekeeping:
    [​IMG]
    I haven't removed any of the electronics yet. It turns out that the pots I got from Stew-Mac are slightly too large, both for the mounting holes and for the knobs. I have a reamer, I can embiggen the mounting holes correctly this time. The knobs though, that might be trickier. But I also wanted to make a template for the wiring, and there isn't much time left for today, so here I will stop for now.
    Goodnight, and thanks for reading.
     
  15. Mr. Lumbergh

    Mr. Lumbergh Gretschie

    432
    May 14, 2013
    Initech, Inc.
    Not much progress this last week, it was a bit of an odd one, but I did pick up a few more things for the build:
    [​IMG]
    What do allthread, aluminum channel, vinyl tubing, and drawer rollers have to do with a guitar upgrade?
    Stay tuned. ;)
     
    Rob Williams likes this.
  16. wildeman

    wildeman Friend of Fred

    May 10, 2015
    norcal
    Don't feel bad man, i blew out the tuner holes on two guitars with a twist drill before learning to use a reamer or step drill. Still own one of them to remind me.
     
  17. wabash slim

    wabash slim Country Gent

    Age:
    67
    Feb 10, 2010
    lafayette in
    You teaser! Inquiring minds want to know!!!
     
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  18. Mr. Lumbergh

    Mr. Lumbergh Gretschie

    432
    May 14, 2013
    Initech, Inc.
    OH, but I do. I should have at least stopped after the first one and reassessed what I was doing, but no. I kept on thinking I could improve things, and I didn't. :(

    So, I decided I'd give a go to mounting the preamp in an enclosure; that was one of the goodies in the order I got from Mouser.
    The goal was to make this:
    [​IMG]
    fit in this:
    [​IMG]
    The enclosure was a bit bigger than I wanted or needed, but was the smallest thing that was deep enough (or so I thought). Still, it would give me plenty of room for the board, battery, two jacks, and a magnetic/piezo selector switch. Measured out and lined up:
    [​IMG] [​IMG]
    Drilled, installed, and Bummer Time. It's coming in about 2mm too short. :(
    [​IMG]
    The lid won't close fully without putting a lot of strain on the components on the board. The enclosure material is thicker than I thought, and pushed the pot for the blend control up too high. Back to the drawing board...
     
    Last edited: Jul 17, 2017 at 3:25 AM
  19. Mr. Lumbergh

    Mr. Lumbergh Gretschie

    432
    May 14, 2013
    Initech, Inc.
    Despite setbacks, some progress today. Color coat down on the front of the headstock to fill the tuner shaft holes gone wrong:
    [​IMG]
    Same for the back, though I'll need to give another go to matching the color; it's difficult to get a hard wood such as maple to take color in any fashion besides grain-on:
    [​IMG]
    One thing I did also notice was this odd wear pattern from where the bridge rested. There's matching worn area on the high E side. Even though the bridge is larger than this small worn area, it doesn't make contact completely. This is one of the things to be dealt with with the most recent Depot buys, as you'll soon see (hopefully):
    [​IMG]
     
  20. Ricochet

    Ricochet Gretschified

    Nov 13, 2009
    Monkey Island
    Desolder the pot and hardwire it?
     
  21. Mr. Lumbergh

    Mr. Lumbergh Gretschie

    432
    May 14, 2013
    Initech, Inc.
    I managed to get food poisoning Sunday night and had to take the last couple days off from work. But, that at least gave me a chance to get some of the more tedious stuff out of the way. The first application of CA glue is applied to the front:
    [​IMG]
    It looks pretty ugly at the moment, but will me masked off, sanded, and buffed. Stay tuned.
    And the screw holes are filled and the color stained to match as closely as I was able the stain on the back of the headstock:
    [​IMG]
    If you look closely you can see where the plug is above the index pin hole for the Sperzel tuner and one right under the tuner shaft hole. Not completely invisible, but not something I think would be noticed at a glance. The staining took a bit more doing, but turned out pretty well, at least well to also not be noticeable at a casual glance. The fill will go on top to even out the tear-out, but for now I'm letting the dye dry thoroughly so that it doesn't make the fill milky.
    I thought about that, and I reckon it'd be the ideal solution so I'm not stuck with a clip on box bigger than necessary, but the board is pretty tight and I would risk wrecking any chance I had to return this thing if something is wrong with it. Also, the pot provides the mounting point for the board, as there are no hole provided for standoffs. They just didn't design it for somebody to use it the way I am unfortunately.