The Lehle Module SW is a true bypass switching unit with a relay and an active pop suppression function, controlled by an incoming signal. Lehle describes it as "a true bypass switching unit with relay and an active pop suppression function controlled by an i" in its spec sheet1. In plain terms, it sits in a signal chain and switches a path in or out without coloring the sound: when bypassed, the signal passes through the relay's contacts rather than through any circuitry.
What it does
The heart of the unit is a relay with gold-plated contacts. Lehle states it is "equipped with a gold-plated contact relay for lossless signal routing"1. Gold plating on relay contacts is used to keep the connection clean and consistent over many switching cycles, which is what a true bypass design depends on: the signal either goes straight through the closed contacts or is disconnected entirely.
The pop suppression is described as active, meaning the unit takes steps to suppress the switch-on noise rather than relying only on the relay's behavior. For a player, that matters most when the switching is triggered by another device or happens while the amp is live, where a pop through the speaker is hard to miss1.
The Module SW offers "three different operating modes: Latching, Momentary or Mixed Mode"1. Latching mode holds the switched state until it is told to change; Momentary mode switches only while the control signal is present; Mixed Mode combines the two. That flexibility lets the same module serve as a held on/off switch or as a momentary effect trigger depending on how it is wired into a system.
Connections and wiring
The Module SW is wired with color-coded leads and defined pin assignments, per the Lehle spec sheet1:
| Function | Lead color | Pin |
|---|---|---|
| Power supply +9 V | Red | Pin 1 |
| Ground | Black | Pin 2 |
| Input | White | Pin 7 |
| Send | Yellow | Pin 8 |
| Return | Gray | Pin 9 |
| Output | Orange | Pin 10 |
The Send and Return pair forms a switching loop: the signal can be sent out to an effect and returned, with the relay deciding whether that loop is in the path or bypassed. The input and output carry the main signal through the unit1.
The Module SW is one of a family of Lehle switching modules. Lehle also lists the Lehle Module SW-L, Lehle Module SW-OF and Lehle Module SW-OFL as related switching units, and larger switchers such as the Lehle Dual and Lehle 3AT1 SGoS for players who need more than a single switch point. For the broader category, see Switching Pedals.
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Questions
What is the Lehle Module SW used for?
It is a true bypass switching unit: it turns an effect or signal path in and out of your chain using a relay, so the signal either passes through the contacts untouched or is routed elsewhere. Its active pop suppression function is designed to stop the click or thump that can occur when a switch closes, which matters when switching is triggered remotely or mid-performance.
What operating modes does the Lehle Module SW have?
Lehle specifies three operating modes: Latching, Momentary and Mixed Mode. Latching holds a state until switched again, Momentary switches only while the control is held, and Mixed Mode combines the two behaviors. Which mode suits a setup depends on whether the switching needs to stay put or follow a momentary control signal.
Sources (1)
- LEHLE MODULE SW Datasheet V1.0.cdr, Lehle GmbH, 2019-09-17
