The Lehle Module SW-OF is a compact true bypass switching unit from Lehle, small enough to sit inside a pedal: the maker says the module is smaller than a 9-volt battery, so it can be placed in a battery compartment or any free space in an effects pedal1. It is built around a relay with gold-plated contacts for lossless signal routing, and an intelligent microcontroller circuit drives the relay and provides an active pop suppression function1.
What it does
The Module SW is a true bypass switching unit with a relay and active pop suppression, controlled by a microcontroller circuit1. In plain terms, the relay physically connects or disconnects your signal path, so the audio never passes through any active circuitry when bypassed, and the microcontroller suppresses the pop that mechanical switching can otherwise produce. Lehle offers three operating modes: Latching, where the switch holds its state, Momentary, where it is only active while pressed, and Mixed Mode1.
The SW-OF is the open frame version of the module and comes without leads1. It sits in a family that also includes the enclosed Lehle Module SW, the Lehle Module SW-L and the leaded Lehle Module SW-OFL, as well as the pedal-format switchers such as the Lehle Dual and Lehle Little Dual.
The Switch Btn bundle
Lehle also sells the module as a True Bypass Switch Bundle together with the Lehle Switch Btn momentary footswitch3. Lehle's argument for the pairing is repair: the maker states that faulty 3PDT switches, the mechanical bypass switches found in many pedals, are unreliable, noisy and very common, and that they can be completely replaced by the module and button combination3. The bundle is listed as available3.
"you get a clickless true bypass switch"
For a player with a pedal whose bypass switch has failed or crackles, the bundle is a drop-in replacement route: the module fits inside the enclosure and the Switch Btn takes over the switching duty3.
Specifications
| Specification | Value |
|---|---|
| Supply voltage | 9V2 |
| Current consumption, off | 7 mA (a second figure of 21 mA appears in the same datasheet)2 |
| Max level | 12 dBu2 |
| Series resistor, LED | 82 Ohm2 |
| Weight | 6 g [0.2 oz]2 |
The SW-OF is the open frame version without leads1. If you need a module with leads fitted, the SW-OFL is the leaded variant in the same range.
Price and availability
Lehle lists the Module SW-OF at €19.90 (as stated on the maker's page, dated 2026-10-25)1, and both the module and the Switch Btn bundle are shown as available13.
Videos
Raul Neves
Questions
Is the Lehle Module SW-OF true bypass?
Yes. Lehle describes it as a compact true bypass switching unit built around a relay with gold-plated contacts for lossless signal routing. An intelligent microcontroller circuit drives the relay and provides an active pop suppression function, so switching is clickless as well as true bypass. It is available on its own or bundled with the Lehle Switch Btn footswitch.
What is the difference between the Lehle Module SW-OF and the SW-OFL?
The SW-OF is the open frame version of the Lehle Module SW and comes without leads. The SW-OFL is the variant with leads attached. Both are true bypass relay modules from the same family, which also includes the enclosed Lehle Module SW and SW-L versions.
Does the Lehle Module SW-OF come with leads?
No. The SW-OF is the open frame version without leads. If you want a module with leads already fitted, the SW-OFL is the leaded version in the same range.
Does the Lehle Module SW-OF come with a footswitch button?
Not on its own. Lehle also sells a bundle that pairs the SW-OF module with the Lehle Switch Btn momentary footswitch; together they form a clickless true bypass switch that can replace a faulty 3PDT switch.
How much current does the Lehle Module SW-OF draw?
Lehle's datasheet lists a current consumption of 7 mA when off, at a supply voltage of 9V. A second figure of 21 mA also appears in the same datasheet, and the two values are not reconciled, so check the datasheet table for the version you own.
Sources (3)
- LEHLE MODULE SW-OF, Lehle GmbH
- LEHLE MODULE SW Datasheet V1.0.cdr, Lehle GmbH, 2019-09-17
- LEHLE SWITCH BTN + MODULE SW-OF BUNDLE, Lehle GmbH
