📡 DL4 Mods 📡

🧨 Disassembly

Remove the potentiometer knobs by pulling or carefully prying with a flathead screwdriver.

Undo the jack nuts.

Unscrew the five screws on the bottom.

Remove the four screws and the hex standoff.

Desolder the battery cables and remove the battery contacts to make room for the external tap tempo jack and the expression knob.

Lift the PCB out by the front (standoff side) edge.

🔩 Switch Replacement

Replace the flimsy original switches with heavier duty ones.

Parts needed	Qty
Momentary SPST footswitch	4

Desolder or destroy the original tactile switches. Be careful not to lift a solder pad or cut a trace.

Remove the old switch bodies by undoing the nut on the outside.

Remove nubs in switch holes with e.g. a file, rotary tool or a 12mm / 1/2" drill bit.

Install the switches without the nut or washers on the inside.

Wire the new switches to the pads of the tactile switches, one wire on either of the top pads, one wire on a bottom pad. (The top pads are connected to each other and so are the bottom ones)

💡 Led Replacement

Parts needed	Qty
3mm/5mm LEDs	4

Desolder the old LEDs.

Using the spacers from the old LEDs, install the new LEDs aligning the longer leg of the LED with the + on the PCB.

If using 5mm LEDs you might have to drill the holes in the enclosure to match.

📚 Double Presets Footswitch

Source

This mod adds a second set of presets by acting like an expression pedal in full heel or toe position.

Parts needed	Qty
Latching DPDT footswitch	1
10K resistor	1

Optional	Qty
LED	1
LED holder	1

Marking the holes is easier if you fit the white footswitch washer that comes with most 3PDT switches in the recess, then find the center. This way the switches shouldn't conflict with the jacks.

You might have to resolder C15 flat if it touches the switch.

Somebody somewhere said one should isolate the switching tip contact of the expression pedal jack, for example by sticking tape between the contacts.

If you're not using the toggle switch to choose between double presets / expression knob, solder the wire from the footswitch to the expression jack tip.

You can solder the wire marked 'Expression Jack Sleeve' to any of these points.

💨 Expression Knob

Source

The expression knob works like an external expression pedal would.

Parts needed	Qty
10K linear potentiometer	1
Potentiometer knob	1

Drill a hole for the potentiometer on an end of the battery bay approx. 20mm from the front edge and 18mm from the bottom, or whatever dimensions suit your knob.

Somebody somewhere said one should isolate the switching tip contact of the expression pedal jack, for example by sticking tape between the contacts.

If you're not using the toggle switch to choose between double presets / expression knob, solder the wire from the potentiometer to the expression jack tip.

You can wire the ground to a bottom pad of a switch.

💱 Switching between double presets and expression knob

Parts needed	Qty
SPDT toggle switch	1

Solder the wire from the toggle switch to the expression jack tip.

🎶 External Tap Tempo

Source

The external tap tempo jack allows you to connect a separate switch box via a cable.

Parts needed	Qty
Mono jack	1

Drill a hole for the jack on the end of the battery bay approx. 20mm from the front edge and 14mm from the bottom

The jack is installed parallel with the tap tempo switch, connecting the jack's tip to a top pad of the switch, sleeve on a bottom pad.

💫 Feedback Loop

Source

This mod adds a footswitchable feedback loop with an optional potentiometer in series to control the amount of feedback.

Parts needed	Qty
Momentary or latching SPST footswitch	1

Optional	Qty
250K potentiometer	1
68K resistor	1
Potentiometer knob	1

The resistor is there to make the whole range of the potentiometer more usable. The values are a bit arbitraty but seem to work.

You can barely fit another footswitch above the power jack. Below it is a nice spot for the feedback amount potentiometer if you don't mind a hole in the preset texts.