The Memphis Mods: The FAT-Cat - Deaf Eddie

FAT-O-Caster Rotary Switch for Strat-type guitars
The Memphis Mods: The FAT-Cat
Suggested by Tom “Tomcat” Whisenhunt
What it is:
The FAT-Cat is a custom model of the FAT-O-Caster, the ROTARY switch that expand the
potential pickup combinations available in your Stratocaster or other "S-type" guitar. It installs
where one of your old tone controls was. FAT-O-Caster switches do NOT replace your 5-way
pickup selector switch - your 5-way still works just like it always did. FAT-O-Casters work in
conjunction WITH the 5-way to give you new combinations. You lose a tone control, but gain a lot
of tones!
The traditional Strat 5-way selector gives you only 5 of the seven parallel combinations possible,
and no series connections. With the FAT-Cat, you can get all seven possible parallel combinations,
PLUS some series combos, for a total of ELEVEN different pickup combinations. Yes, this one
goes to eleven!
That's a lot of tones!
BEST OF ALL, NO NEW HOLES!
Just put your old tone knob back on the FAT-Cat switch, and your Strat looks completely stock!
Your stock Strat is wired like this:
Look at your guitar and identify all the leads you see here. Ready? Go…

INSTALLATION:
Remove the center tone control:
Take off your pickguard. Wire your lower tone as a "master" tone (like a Telecaster):
1. Move the lower tone control’s lead from the center lug of the tone control side of the five-way
over to the common lug on the other pole of the five-way. Do NOT remove the jumper between
the common lugs. If this is a “new build,” be sure that you add that jumper.
2. Remove the lead to the center tone control from the five-way.
3. Remove the grounds from the center tone pot, and clip any jumpers between the center and
lower tone pots. Remove the center pot from the pickguard.
4. Remove the capacitor from the center tone pot and wire it to your new MASTER TONE pot,
with one leg on the center lug and one leg grounded to the back of the pot.
5. Run an insulated ground wire from the back of the volume pot to the back of your new master
tone pot, with enough slack to go around the FAT-O.
Mount the FAT-O-Caster Switch in the place of the center tone pot.
DO NOT OVERTIGHTEN THE MOUNTING NUT!
You will notice that the switch is NOT perfectly round, more egg-shaped - align it so that it's
widest parts "point" to the other two controls. If your control cavity is shielded, be sure that the
lugs on the switch DO NOT touch/short out on the shielding.
NOTE: While FAT-O-Casters are a "straight swap" on genuine Fender guitars, others may have to
slightly enlarge the hole in the pickguard, and still others have reported that the control cavity must
be routed a little deeper to accommodate the switch, which is "deeper" than a normal pot.

Connecting your pickups to the FAT-Cat Switch:
Unsolder the bridge pup’s negative (aka “ground”) lead from where it is currently in your guitar
(typically on the back of the volume pot) and solder it to the center lug on the FAT-O with the
STRING TIED THROUGH IT (cut the string off!).
Unsolder the mid pup’s negative (aka “ground”) lead from where it is currently in your guitar
(typically on the back of the volume pot) and solder it to the next center lug on the FAT-O,
CLOCKWISE.
NOTE: Sometimes there is not enough wire on the ground lead to make it to the FAT-O, so just add on a little "tail" to
the lead to get there. Be sure you insulate the solder joint on this "tail" to prevent contact with the pots or any other
grounded surface in the control cavity – black electrical tape will do…
Three-wire pups? MOST COMMONLY, two of the three leads are twisted together and soldered to ground. You will
have to determine which wire of the two that goes to ground is actually the coil’s “-“ lead, and which is the
ground/shield drain. The easiest way to do this is to unsolder them from ground and separate them. With a multimeter
set in the 20k ohm range, touch one probe to the pickup’s “+” lead, and then try the other probe on each of the other
leads. The pickup’s “-“ lead should show you the impedance reading for the pickup – typically between 6k and 8k for
a Strat. The ground/shield lead will show “open” – no resistance, no continuity. Solder the ground/shield lead back to
ground, and solder the pup’s “-“ lead to the switch as instructed above.
Wiring the FAT-O’s pre-wired leads:
The RED lead is soldered to the 5-way switch. It goes on the lug that would be the bridge lug of
the second pole of the selector switch (the side used to connect the tone pots - see drawing).
The GREEN lead is added to the middle pup’s lug on the 5-way
The BLACK lead is added to the neck pup’s lug on the 5-way.
The bare wire is soldered to (any) ground.
Put your pickguard back on, and you're ready to rip!

Wuzzit do?
Well, for starters, you now can select from 11 different pickup combinations!
Yes, some of the tones are repeated - but that's what makes this thing so darn easy to use…
So, WHAT are the new tones, and WHERE are they?
I like to count the settings this way: the FAT-O-Caster switch has “notches” we'll call 1, 2, 3 and 4,
numbered as you turn the switch COUNTER-CLOCKWISE. So, if it was a tone control on “10”,
you would be at notch 1. As you turn the control “down,” like from ten to, say, seven, you go
through the notches 1 through 4. Remember that even though you have the FAT-Cat installed, the
5-way still controls the pickups – think of it as having FOUR different selectable bridge pups!
Here's what to expect from the 5-way at each FAT-Cat notch:
Notch 1 (“tone knob” on “10”) is just normal Strat tones.
El Stock-O…
NOTE: As a reference for the rest of these instructions:
Throws on the 5-way: 1=neck, 2=middle and neck, 3=middle, 4=middle and bridge, 5=bridge
Notch 2 (“tone knob” on “9”) is the "NECK on with BRIDGE" setting –
the neck pup is ALSO routed to the bridge end of the 5-way switch.
The combos are all wired parallel.
As you throw the 5-way in this setting, you get (from 1 to 5):
1 = neck
2 = neck and middle
3 = middle
4 = bridge, middle, and neck
5 = bridge and neck
There now, isn't that what you've always said you wanted your Strat to be able to do?
Notch 3 (“tone knob” on “8”) is the “SERIES with Neck" setting.
In 1, and 2 it's neck only.
In 3, you have mid in series with neck
In 4, you have (mid parallel to bridge) in series with the neck
In 5, you get bridge in series with neck
Notch 4 (“tone knob” on “7”) is the "All Three SERIES" setting.
In 1 and 2, it's neck only.
In 3 and 4, you get mid in series with neck.
In 5, you get the all three pups in series - YIKES!

A few other common 5-ways:
Import “in-line” style:
The “non-CRL” from Stewmac and others:
The Mega–S switch’s lugs are in a completely different configuration: