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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.