MOD 1: Make Your TS9 True-Bypass
Tools and Parts for This Mod
• Power drill
• 1/2" drill bit
• Wire strippers
• 3PDT footswitch
• 2.2k–4.7k Ω resistor
• Three jumpers (these could be clippings from
the leg of a resistor or capacitor)
• Two or three 3" pieces of wire
• Needle-nose pliers (handy, but optional)
This mod requires drilling a big ol’ hole in the middle of your Tube
Screamer’s case. Here goes nothing, right? I know it sounds crazy,
but it has to be done so you can install the shiny new 3PDT (three-pole,
double-throw) footswitch that’s necessary to make your pedal
true-bypass.
Photo 1 (left): Components and wire leads to be removed from the main TS9
circuit board. Photo 2 (right): Replace the original short jumper wire with a longer one extending
to the hole where the bottom leg of a 510k Ω resistor used to be.
1. Desolder the red-and-white-striped
wire from the circuit board
(upper-left corner in Photo 1) and
cut the black wire that connects
the input jack to the original footswitch.
This allows you to remove
the circuit board from the case.
2. With the circuit board
removed, drill a 1/2"-diameter
hole in the middle of the case
where it says “TS9” (under the
Ibanez logo). You may want to
prop your pedal up on blocks so
that the top is level and you can
get a straight shot at the surface
(otherwise, the hole will end up
being elliptical instead of round).
3. The TS9 uses what’s called
a “flip-flop” circuit to turn on
and off, but with the new true-bypass
switch, the parts in this
circuit aren’t necessary. Remove
the following:
• Two FETs
• Two 510k Ω resistors
• Two diodes
• The jumper wire
• The capacitor labeled
“104” (it’s the blue cap at
lower-right on this board,
but it may be a different
color on yours)
4. Desolder the end of the pink
wire on the main circuit board
that connects to the LED’s circuit
board.
5. Remove the short jumper
wire (bottom middle of the
circuit board in Photo 2) and
replace it with a longer jumper
that begins at the same right-side
hole as the previous jumper but
extends to the hole in between
where the two FETs removed
in step 3 used to be. The correct
hole previously contained the
bottom leg of one of the 510k Ω
resistors also removed in step 3.
(Note: Disregard the two clear
LEDs that appear in place of
clipping diodes at middle right in
Photo 2—they were from a previous
mod.)
6. Now that most of the board
work is done, let’s move on to
the footswitch. To make wiring
more convenient, place it
upside-down in the case, with
the holes in the lugs facing you
(see Photo 3). Referencing the
schematic in Fig. 1:
• Connect pins 2 and 9 with
a jumper wire
• Connect pins 7 and 8 with
a jumper wire
Note: Make sure the jumper
wires don’t touch any other lugs.
Fig. 1: Schematic for wiring a 3PDT true-bypass footswitch.
7. Desolder the yellow wire at
the upper right in Photo 1 (it’s in
the hole labeled “11”) from the
main circuit board and solder it
to footswitch pin 2. See Photo 4.
8. Solder one end of a 3" wire
in the now-empty hole 11.
Solder the other end to footswitch
pin 5.
9. Desolder the white wire
from the upper-left corner of
the main circuit board (the hole
labeled “1”).
Photo 3 (left): Prop the new 3PDT footswitch
in the newly drilled hole for
convenience while soldering jumper
wires and other leads. Photo 4 (middle): The true-bypass switch
with steps 7–14 completed. Photo 5 (right): A completed TS9 true-bypass mod.
10. Solder one end of a 3"
wire (or you could reuse the
red-and-white-striped wire) in
the now-vacant hole 1. Solder
the other end to footswitch
pin 3.
11. Solder the white wire from
the output jack to footswitch pin 6.
12. Strip a little insulation off
of the pink wire.
13. Solder one leg of your new
2.2k–4.7k Ω resistor (resistors
aren’t polarized, so it doesn’t
matter which leg) to the pink
wire. Connect the resistor’s
other leg to footswitch pin 1.
14. Solder one end of a 3" wire
to the sleeve lug of the input
jack, and the other end to footswitch
pin 4. If you’re having
trouble finding the sleeve lug,
here’s how: See how the jack
has three lugs, one with a yellow
wire, one with a black wire
going to the battery terminal,
and one with a black wire going
to the output jack? That last
lug—the one with the black
wire going to the output jack—is the one you want to solder to.
15. Connect the new footswitch
to the pedal housing.
Congrats—your TS9 is now true-bypass!
Your footswitch should
look something like Photo 5
when it’s done and installed.