Updated by Bobby
Updated on December 10th, 2020
Since the G-400 is no longer carried (or at least much harder to find) we linked instead to the Epiphone SG Standard. All other product links are accurate and up to date, as of December 10th. Also made minor changes to article formatting.
Quick Summary: In this build guide we take on an Epiphone G-400 SG, replacing the stock pickups and volume pots with Seymour Duncan Saturday Night Specials and 500k volume pots from StewMac.
For this upgrade we bought a brand new Epiphone G-400 SG (also works with the Epiphone SG Standard) which would be considered an "okay" budget guitar.
Our task was to replace a few components and make it into a much better-sounding, more capable instrument that could, perhaps, satisfy those who had surpassed the beginner stages.
To do this, we planned to replace the following components:
- Both stock pickups (bright and neck position)
- Both volume pots (one for each pickup)
- The strings that Epiphone ships with the guitar
Please note: We actually bought all of the parts that were used in this build guide, including the guitar itself. Here's a full list of what we had on hand for the pickup upgrade:
Epiphone SG G-400/Epiphone SG Standard
Seymour Duncan Saturday Night Special Pickup Set
Elixir Electric Strings
Alpha Push-Pull Volume Pots (500k)
The Saturday Night Special pickup set from Seymour Duncan was the core of the upgrade, adding a more classic-voiced tone with Alnico magnets and a warmer EQ profile, yet with plenty of treble on the high end.
With modifications, we loosely followed this wiring diagram for two push/pull volume knobs and a three-way toggle:
Note that in the diagram, the Seymour Duncan-branded volume pots are just placeholders and will be different if you use the existing Epiphone pots or the Alpha pots like we put on. In this guitar configuration there is a volume and tone knob for each pickup.
Tone Before the Upgrade
Just to get a feel for how these upgrades transformed the tone of the guitar, here are a few sound clips from before we made any changes to the Epiphone SG. This is what it sounded like straight out of the box, with nothing but a quick tuning.
We used two fairly basic amp models in GarageBand, the first for a low-gain clean setting:
And the second for a high-gain "dirty" tone:
Tone After the Upgrade
Before we get into any of the details of the upgrade, here's what the Epiphone SG sounded like after all the work had been done, namely adding the pickups, the new volume pots and a fresh set of Elixir strings:
The first setting was similar to what we used in the "before" sound samples:
We then tested it through a heavier amp model with higher gain and more treble in the three-band EQ:
Now that you've heard the difference in tone, let's go quickly through the modding process and show you how we installed the parts and what tools were needed to do so.
Epiphone SG Pickup Upgrade: The Modding Process
While this process is always subject to change, depending on parts, we can go through a generalized step-by-step retelling of how we installed each piece. Before doing an upgrade like this, it's necessary to have the following tools on hand:
Digital Soldering Station
We used an older digital soldering station from RadioShack, but you can get newer ones everywhere, often without cracking three figures.
Here's the soldering gun that comes with it:
While not crucial, we also found that having a multimeter around to test soldered wire connections was pretty helpful, especially when putting on the new volume knobs and trying to figure out the wiring.
Removing the Pickups and the Volume Knobs
The first thing we did was remove the strings, volume knobs and the existing Epiphone pickups. We used blue tape to keep the volume pots from falling back into the body of the guitar (this was before we put in the new volume pots).
Once that was done, we were able to wire the new Seymour Duncan pickups through the bridge and neck guitar positions. Note that the ends of the wires are wrapped together, so you'll need to unwrap these and strip all the smaller wires.
Once the wires were pulled through we noticed that the existing circuit boards on the stock volume pots were extremely cheap and wouldn't even hold a wire because the plastic was so weak.
We ordered the push/pull Alpha 500k volume pots from Stewmac, which have much nicer circuit boards.
Notice the six metal pins coming off of each new volume pot. These are much stronger soldering points than the plastic rings on the old stock volume pots that came with the guitar. Upgrading these was a necessary, yet affordable way to upgrade the quality of the guitar.
The specifics of wiring the pickups to these or other volume pots will depend largely on the type of configuration you want and weather or not you want to use coil tapping. We were able to follow the provided wiring diagram by Seymour Duncan and get both pickups working with the coil tapping functionality intact. Positioning of the small black wire and the main lines coming off the tone pots should be consistent.
Once all the wires were in place, we tucked everything into the back of the guitar and set the volume pots in place using the provided screws to hold them to the body and put the two volume knobs back on.
We now have a working volume control and coil selector for both the neck and bridge position pickups.
After that, the last task was to put on the Elixir strings and try it out. The pickups sounded and worked great (refer to the "after" sound samples from earlier in the article) and the improvement in tone was significant.
Conclusion and Questions
As mentioned, the wiring can be the trickiest part, which is difficult to speak to without knowing the particulars of your upgrade. If you're following along with the products we bought, use the Seymour Duncan guide that comes with the pickup set and make sure you follow the "coil tapping" configuration.
If you have trouble, use a multimeter to test for connectivity in each wire and make sure that your soldering is thorough.
Otherwise, if you have questions about the process, the electronics involved or the parts recommended, feel free to get in touch via the comments section below.
Written by GC Editorial on Electrics and Build Guides
Alan Cargile says
That was a very interesting article. I’ve been modding my guitars for many years so I understand everything that you did. Great job! I recently bought an Epiphone 1961 Les Paul SG with the Gibson Burstbuckers and CTS pots. This instrument is very gig ready and sounds great. I use it over my Fenders and Carvin. Anyway keep up the good work my friend!
Hey, thanks Alan – when I did this, I relied a lot on my buddy Everette for the more technical stuff. The sound we got out of the guitar turned out pretty good though. I appreciate the kind words. As far as your Epiphone goes, Gibson Burstbuckers seem to go a long way. I’m a big fan of those sets.
Help me please )
I’ve got G-400 PRO (made Sen. 2019) from thomann-shop.
There is 2 small SMD components on small pcb’s, that soldered to each push-pull volume pots.
One of them (SMD) is black and has marking “124”. The another is brown and i don’t see marking.
It seems (i don’t want dismount all of this from guitar) that those smd’s soldered in series.
Is this some kind of “Kinman treeble bleed mod” ?
If yes – does it works in both (“push” or “pull”) positions?
Nikki Magnusson says
I want to swap out the pcbs in my Epiphone SG…to traditional wiring.. can you recommend pots that drop in with no body mods.. I guess it’s a metric short shaft 10mm?.. I have the Gibson Seymour Duncan Slash zebra pickups ready..soldering station spools of wire…wiring harness with orange drops needed also.. I hope I don’t mess this up .sigh
Hey Nikki – I would think most pots will fit without any kind of modification. I’d personally try the Dunlop Super pots. https://www.stewmac.com/electronics/components-and-parts/potentiometers/dunlop-super-pots/
Thank you. I’ve never replaced pickups where I soldered anything. My last sat was in a Strat and everything was integrated into the pickguard already where I just had to plug the wires in and screw em down. This guide should help with the Saturday Night Specials I just got for my SG.
There’s a bit of a learning curve, but just take your time and you’ll get the hang of it. Good luck.
Nethan Paul says
Nice article to know replacement process of sound parts for better sound. I need to replace the components which can enhance its volume performance. But I also need to repair strings and tuner buttons. After reading the blog I am confident how to replace the sound components but side by side I also need to know the replacement process for keystone tuner buttons and strings. Please provide me some suggestions on this. Thanks a lot.
Bobby Kittleberger says
Hey Nethan – are you talking about the tuning heads? What kind of guitar are you trying to mod?
Braulio Castellanos says
Great tutorial; It is something I plan to follow in the near future. Thinking of using Pearly Gates vice the Saturday Night Specials.
Bobby Kittleberger says
Thanks, Braulio. Glad it was helpful.
If you have questions during your upgrade, feel free to post them here.