SG copy overhaul & P-Rails upgrade

Ok Wokks, just to satisfy your endless curiosity…

A couple of months ago I noticed a cheap SG copy on sale which with an additional discount I had available dropped it down below half price. I wasn't expecting too much from it, but the price was worth it just for the looks. Supposedly Mahogany body and neck, wine red colour with a 14" radius fretboard. Couldn't resist.

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There were few obvious flaws. A screw was missing from the bridge pup ring, there had been a light knock on the edge of the body and one or two on the headstock that had just slightly cracked the finished (tiny, not enough to worry me) and the bridge tone control wasn't working.

I soon found the cause of the tone control issue. If you look closely at the lower right tone pot you can see a leg of the cap is shorting to the pot input thus ignoring the pot and sending all the signal to the cap. It also explains why the bridge pup sounded so dark.

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Roomy cavity, but not for long.

The end of the fretboard was also very gnarly, the G & B strings choked out a touch up high on bends, and the treble fret ends beyond around 15 were a bit sharp and spiky.

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You can actually see the fret ends are raised a little over the binding in the above pic.

The truss rod was waaaay over-tight, I've never had to back a truss rod off so much before to try and get a touch of relief in the neck. Tweaking the neck and action over a couple of days I eventually got it playing quite nicely, although the neck really sensitive to adjustment. Slight tweak, no change, a touch more and it goes way too far. Very touchy. Tuners seem fine, bridge sits a little higher than I like, but is Ok. The saddle slots are a bit 'one size fits all', so may replace them or the whole bridge one day. The finish is pretty thick in places, hiding some obvious manufacturing flaws (particularly on the headstock), but I can live with it.

I was going to leave it at that for now, but after a few weeks with it I realised I just love the feel of it. The neck is a touch wider at the nut than the PBG necks, around 43/43.5mm, and just has something about it. So, I committed to an overhaul and upgrade...

I've been sitting on a set of SD P-Rails for while ready for a future build, so I figured rather than have a good of pups doing nothing I may as well give a run in this along with a few wiring tweaks.

Pulling knobs. Twist a loop of cord, slip it over the knob, tighten and pull up. Done, no marks on the surface.

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Removing the loom.
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Interestingly, the pots are 500KB's (linear) for the volume and 500KA's (log) for tone. That gave me an idea.

Stock pups out, 8.9K neck and 16.3K bridge (hotter than I expected). They sounded ok.

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(I wrote the values on them)

I also wanted to replace the plastic nut with bone, so carefully scored around it with a sharp blade and then a few taps with dowel and hammer.

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Strangely, there was a hole at the bass edge of the 1st fret from near the binding going in and a larger hole going deep in from the end of the fretboard that had been hidden by the nut. You can also see the usual holes typical in plastic nuts.

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I plugged the deep fretboard end hole with a rosewood plug, and used rosewood dust and superglue to fill the smaller one.

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Set and ready for a trim, sand and cleanup.

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I pressed all the frets to make sure they were seated, particularly the high ones with the sharp ends. But, the sharpies just wouldn't stay seated, you could actually see them lifting as the pressure came off. Sad face.

I wasn't going to re-fret, at least not yet, so the only other option was to wick in some superglue and fix them down that way.

Glue wicked in, caul on the underside of neck, radius block with card layer on top of frets and clamped as firmly as I dared.

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As an aside, the bridge ground wire hole runs from the pup rout intersecting with the bottom of the bridge post hole and then on into the control cavity. You can actually tap the bottom of the post bushing with a thin rod down the hole. If you ever need to drill a hole for a TOM bridge ground, that may be your shortest and easiest option.

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Fret Levelling: black marks the high spots, red everywhere else.

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Re-crowning.

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Dressing the fret ends… awesome little file with a rounded safe edge. No more sharp ends on the upper frets.

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Final cleanup and steel wool'ing.

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Rough fretboard end smoothed. Fretboard sanded, scraped and then two applications of Dingowax. I don't have a photo, but you can't even see the rosewood dust repair on the 1st fret now.

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Roughing out the bone nut, going with a vintage vibe. The fine saw cuts will be my guide for the files.

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Good enough for now, will finalise the nut once it's all assembled and settled.

The new vital organs.

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Shields up! Given that the P-Rails will be used with individual P90's and Rails selected, noise will be an issue like with any single coil pickup so full shielding is needed.

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Shielding soldered on the seams to ensure continuity, and tape added below where the pot lugs will sit to protect against possible shorts. The original bridge ground wire is still in place, so I added (and soldered in) an additional wire that links the shielding in all the cavities and will connect to ground.

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Oversize strap buttons added… mainly to reduce paranoia with something neck heavy like this.

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Transplant successful. The neck pup lead is only just long enough for what I need to do with it. And yes, I know the neck pup is flipped, it's intentional. It makes little difference to the position and sound of the P90 but is a big change for the Rail, the idea being to get a bit more quack when it's combined with the bridge Rail.

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So, about that idea the stock pots gave me. Linear (B) pots aren't typically used for volumes these days, instead we use log/audio (A) pots as they're more suited to how we hear volume changes. A 'B' pot is 50/50 resistance at halfway point whereas an 'A' pot is closer to 80/20. But, the old, old log pots used back in the 50's could sometimes be closer to 60/40 or even flatter, so linear pots are actually closer to what's in some of those old school looms. So, I thought, why not see how a pseudo vintage style loom goes with the P-Rails.

I wanted to be able to select each individual coil on each pickup, which meant four push/pulls. And, given that they would be working with both humbuckers and single coils I wanted something in-between 500K and 250K. I dug around and tested my push/pulls until I found the smallest 500's I could: two 440K B linear pots for volume, and two 450K A log pots for tone. Switchcraft jack and 3-way toggle switch, and Paper In Oil caps (yes, three of them).

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The plan…

- 50's style wiring with the tone pots linked via caps to the 'out' of the volume pots (rather than the modern 'in').
- Push/Pull Volume and Tone for each pickup, allowing access P90, Rail, Series Humbucker, Parallel Humbucker combinations.
- Cap switching on the neck pickup: 0.015uF cap is active for P90 & Series Humbucker, and 0.022uF for Rail & Parallel Humbucker.
- 0.022uF cap for bridge pickup.

Here's the wiring layout:

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The P90's will likely be my goto when splitting, so I've put them on the volumes and the Rails on the tones. I love the sound of the tone wound off a bit on the neck pup, but not fully dark. So, I've decided to try a PIO 0.015uF cap on the neck for the thicker sounding Series Humbucker and P90 settings, but stick with an 0.022uF cap for the thinner Rails and Parallel Humbucker. The Rail and Para Humbucker are only active when the tone pot is up, so the cap switching is linked to the neck tone push/pull.

Layout template from the cavity holes spacings.

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All wiring completed except for connecting the pickup leads. I can never bring myself to clip the leads on PIO caps unless I absolutely have to… and just in case I move the loom to something else in the future.

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Installed and pup leads connected.

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Buttoned up and tap tested with a headphone amp…. all systems go.

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And, done! Just need to finalise the nut in a few days once everything has settled into place.

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The neck pickup sounds great, I'm really digging it, and the 0.015uF cap gives some nice control and retains a snap on the P90 when wound off. Very pleased. The bridge pup seems a little fussier with its height adjustment, still dialling it in, we'll see. Overall, pretty happy.

another excellent walk through Weirdy, I'll have a good read of the thread. And thanks for satisfying my curiosity !

nice thread Weirdy I read it all in detail. Its come up a treat. Did you already have a 14" radius block ? not a standard size.
Love the idea to remove the knobs with the cord. Beats using 2 flat hear screwdrivers !
Glad I wasn't wiring up that diagram ! nice tidy job on the wiring !

Yep, I already had the 14" block. I did have a 'ruh roh' moment when testing the wiring prior to installing it and connecting the pups, as it was getting continuity between hot and ground. Turns out it was just a wire shorting across a push/pull lug that I had to leave loose for when I hooked up the pups, but still brief panic. It's always wise to fully test before installing, just in case.

Awesome write up Weirdy. Truely inspiring for the rest of us novices. Can't wait to hear the audio demo....please!!

Great write up and pics, at least you didnt have to consult for wiring help!
Are those the ones JB sell? Always wondered about the quality, so inexpensive - and you've made it into a beast!

Yep, they're the ones Stan. They look good, feel good and can play reasonably well but need a lot of setup (at least this one did). Definitely some QA issues that wouldn't be good for a first time buyer.

Based on this one I'd say the quality is a couple of steps down from similarly priced LTD's, but the LTD would be plainer (basswood vs mahogany etc). But, for a half-price mahogany set neck SG as a potential upgrade platform... bargain. Worth a look if you see them on sale, you may find a good one.

Nice tutorial Scott. Any plans for a sound demo?

Cheers, Waz

Quote:

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Originally Posted by WeirdBits

I did have a 'ruh roh' moment when testing the wiring prior to installing it and connecting the pups,....

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Welcome to our "everyday" Weirdy. ;)

Great post, thanks for taking the time to put it up, its given me some ideas

Quote:

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Originally Posted by wazkelly

Nice tutorial Scott. Any plans for a sound demo?

Cheers, Waz

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I carry that motion!

For those interested...

They need a bit of work, but mahogany body and neck currently $158 for passive and active versions.

14" radius necks.

they look pretty good Weirdy. JB in WA don't sell musical instruments but could always get one posted.
Edit just checked and 2 stores in Perth have them !

It's still my current favourite build/upgrade Wokks, and the first thing I reach for.