Fixing an Epiphone Special

[colin2121]

I have an old Epiphone Special which is basically a LP style body with bolt on neck, 2 humbuckers, 1 tone, 1 volume.
The shaft on the tone pot fell out (I take good care of it so it should not have come adrift) and I thought I might have a crack at re wiring the guitar.
I have some 4 wire humbuckers which I can put in so thought I might try and coil tap them so that I can also get single coil as well as humbucker tones out of the guitar. (The original humbuckers are pretty ordinary so no loss to replace them).

The existing pots are stamped as follows
Volume - B500K
Tone - A500K and attached is a green capacitor which looks like it is numbered ZA223J

I am going to replace both pots (if one falls apart that easily then the other should probably go as well) as well as the three way selector switch (always fell a bit fragile) and I might as well put a new capacitor on the tone as well.

My questions:
1. What pots should I get for the volume and tone (A or B)? (I am thinking that the tone pot should be the coil tap variety)
2. Which capacitor should I get for the tone?
3. Is there anything I need to look for with the replacement three way switch?
My guess is that I will also need some pushback wire to join it all together.
I have bought some bits from the guitartrade web site before so will probably get what I can from there.

Any guidance is gratefully accepted - I am very much a novice on the wiring side.

Thanks in advance.

[Dedman]

Hi Colin, the B pots are Audio taper, the A pots are Linear taper, so yep get one of each. Personally I usually split on the volume pot as its closer to hand, but there is no reason you can't do the Tone, or split the neck on the volume pot and the bridge with the tone pot for even more choices. Push pulls are available in both A or B. ( I just bought some Alpha push pulls, I generally go with them , Bournes or CTS)
Generally a 500k cap with humbuckers. ( Orange drops are good and not overly huge)
get a reasonable quality switch and you should be good for years to come.( I usually use the Realtone ones)
The push back wire is easy to use, saves stripping ends but any suitable gauge wire will do. I usually do all my "hot wires" with the white stuff and all my earths with the black.

Cheers

[Simon Barden]

Hi Colin, the B pots are Audio taper, the A pots are Linear taper, so yep get one of each. Personally I usually split on the volume pot as its closer to hand, but there is no reason you can't do the Tone, or split the neck on the volume pot and the bridge with the tone pot for even more choices. Push pulls are available in both A or B. ( I just bought some Alpha push pulls, I generally go with them , Bournes or CTS)
Generally a 500k cap with humbuckers. ( Orange drops are good and not overly huge)

Be aware that with most pots, A normally stands for audio/log taper and B for linear taper. There is no international standard for this, so you occasionally find some pots marked opposite to what is the norm. The only way to be certain is to buy a named brand pot, where you can check on their website what convention they are using. Obviously buying from eBay or Amazon or a parts website, the description will tell you what sort of pot you are buying, but if you buy two audios and two linears and they come unmarked in the same bag and are only marked A and B (some pots have log or audio or lin on them which helps), then you still need to know.

If you have a multimeter (and if you don't, it's a good idea to get a basic one), then you use it to measure the resistance of a pot at its halfway point. A pot has three connections available. The outer two are connected to the ends of the resistance track, the middle one to the 'wiper', that moves around the track to obtain the varying resistance. Set the pot to roughly the mid-position and you should measure around half the pots resistance between the middle connection and either of the end connections. With a log pot, you'll normally get about 20-30% of the pot's value (depending on the exact taper used) between the middle and one of the end connections, and 70-80% of the pots value between the middle and the other end connection.

500k ohms is the standard pot resistance used for humbuckers and P90s. 250k ohms is the resistance normally used for most other single coils. If you want to use switched pots for the coil taps, then you'll find that they'll normally be fitted with the 18mm Ø 'mini' pots rather than the 24mm Ø 'standard' pot. CTS (standard Gibson fitment), Bourns or Alpha are good makes.

Dedman has accidentally confused pot resistances (500k) with capacitance values. Your capacitor is a 0.022μF/uF (microfarad) capacitor, which is standard fitment for use with humbuckers. 0.047μF is normal fitment for single coils. Orange drop capacitors are a good choice - not too expensive but pretty good tolerance, so don't vary too much from the quoted value.

[Simon Barden]

I'd remove the existing 3-way switch so you can see what length of screw shaft you require on your switch. Gibson LP types normally have a reasonable thickness of wood for the shaft to pass through so have a long screw section, whereas if they are fitted on a pickguard then the shaft is much shorter. So make sure the switch is suitable for your needs. I find the 'open' type of switch much more reliable than the enclosed 'box' type.

Realtone sell Allparts products, which themselves are normally major brand products. The Allparts pots are made by CTS. The Allparts branded toggleswitch is in fact a Switchcraft one. Here's a pic of one from the Allparts website and you can clearly see the Switchcraft name on it. Switchcraft are good.

[wazkelly]

I tend to use Audio taper pots for everything, volume & tone, that way you can mix 'n' match without too much drama plus I prefer the smoother roll off on both. Bourns 500k push/pulls from Real Parts along with the switch above and 0.22 orange drops. Should probably go all the way and replace jack socket too with a USA built one. You will probably find the pot threads and jack socket thread diameter a bit larger and suggest using your drill in REVERSE to avoid tear-outs when enlarging the existing holes.

Cheers, Waz

[Simon Barden]

0.022uF Waz. That extra 0 is very important! 0.22uF would be very dark and dull indeed and with that much capacitance, you might even hear them working even with the tone at 10.

[wazkelly]

Oops, missed a decimal place.

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