Revolutionizing the market - Lehle Components

May 09, 2020

German engineer Burkhard Lehle unveiled his plans for the Lehle Components a few years ago at the NAMM show. He would release his own line of audio components, which would include brand-new designs alongside his older inventions. A new switch would be the demise of the old-style, unreliable footswitch. It took a while, but when Lehle finally introduced their Lehle BTN-switch, it was an easy replacement for any regular momentary footswitch and became an instant hit!

IN THE PAST, momentary switches were mainly used as tap tempo-switches or in programmable bypass loopers, but these days they are also widely used as bypass-switches in relay-switched effect pedals. We’re talking about such effects, as – for example – all Strymon pedals, or Walrus Audio’s two-switch effects, such as the Slö and the ARP-87.


We have been replacing regular switches with the Lehle BTN's for some time already. Typical cases are true bypass -switchers, which often see a lot of action on pedalboards. This modification was made to Mikko Von Hertzen, just before the Kingston Wall by JJylli, Kuoppis & VHB  -shows in 2019.

As the name says, in a momentary switch the switching contacts only touch each other while the switch is pressed down. The contacts are released the instant the foot is taken off of the pedal.

The main advantage of momentary switches is that they work smoothly and quietly, without causing any audible clicking noises. You can easily spot a momentary switch, because most of them have only two soldering tags.

Lehle Module SW

Lehle recently introduced their eagerly anticipated Module SW -relay module, which enables you to replace noisy 3PDT-switches with a Lehle Switch BTN-switch.

The Module SW is a little smaller than a nine volt battery, making it easy to install inside a pedal’s battery compartment with 3M Dual Lock or Velcro.

One of the module’s best features is that it’s programmable: in addition to regular on and off switching, you can also use the module for momentary switching action. You can also program it, so that one short push will turn the effect on and one short push will turn it off, while keeping the switch down will turn the effect on, and releasing the switch will turn the effect off again.

Case: Anssi Kela and the Electro-Harmonix Synth9

Shortly after we had received our first shipment of the Lehle module, we were faced with a job, where we could make good use of it. Finnish hit-making singer-songwriter Anssi Kela was in preproduction for his series of intimate biographical acoustic shows.

We had already built Anssi a dedicated pedalboard for use with his acoustic guitar; the board included a tuner, an outboard preamplifier for his guitar’s pickup system, an EQ, and a Lehle Acouswitch IQ DI-box. Because the new shows were to feature only the man and his guitar, he required a few additional “spices” in his signal chain, which is why we added a Boomerang audio looper, Walrus Audio’s brilliant Slö pedal, as well as an Electro-Harmonix Synth9 guitar synthesizer.

There was one problem with the synth, though – each time the built-in switch was used, there was a discernible mechanical clicking noise. In band use, such a click would be drowned out by the other instruments, but in an intimate acoustic gig this noise was unacceptable. The worst case scenario would be if, during live audio looping, one of these clicks would end up being recorded as part of the loop. This looked like a good acid test for the new Lehle module.


We started by opening the pedal up, and by using a multimeter to check the original switch’s polarity. We faced our first little problem: this was a buffered effect pedal, meaning that the switch was wired differently, compared to a standard true bypass-circuit. Mechanically, though, this was a regular 3PDT-switch, which meant that we would, in all likelihood, be able to make use of the module, even if we would have to get a little creative.

We unscrewed the original switch and unsoldered the flat cable that connected it to the main circuit board. We installed the Lehle Switch BTN-switch and connected it to the corresponding cables of the Module SW. Then we soldered the module’s power cables to the effect’s DC-connector.

This was the easy part, but now we stepped into uncharted territory. We had to proceed making educated guesses and using trial and error. After a few steps we managed to get the pedal up and running, but there was still a nasty pop, each time the effect was turned on.

At first we suspected that there must be some DC leakage into the circuit, which we tried to filter out with some capacitors and resistors. We soon found out, however, that the problem was caused by something else, and none of our added components made any clear difference.

Because the actual switching of this effect happens on the circuit board itself, and not inside the switch, we started taking a much closer look at the original switch. We had to find out how the old switch was meant to work in the pedal, and we had to do it without a circuit diagram.

We could brag and boast that we had a sudden flash of genius that made us realize how the circuit had been meant to work. In reality, though, we had to try systematically several possible wiring options, before we got it right. The effect now could be turned on and off perfectly quietly, which was our main objective. But, alas, our problems weren’t over yet. Now the indicator LED was switched on all the time.


Our solution was to remove the LED from the circuit board, glue it in place in the pedal’s casing, and then solder the module’s cables directly to the light’s contacts. Now everything worked! The effect switched on and off in dead silence, and the LED, too, lit up and went out correctly.

 

Our first use of the new Lehle products was a little bit hit-and-miss, but the end result was fantastic to witness in this type of pedal. In view of the intimacy of the show, the quiet switching action proved really very important. We felt we were at the threshold of a new era.

9.5.2020 Eetu Lehtinen and Kimmo Aroluoma

Eetu Lehtinen is Custom Boards’ pedalboard technician and a gifted craftsman, who is in charge of wiring up our boards. In his spare time Eetu plays the bass guitar in the bands Demonic Death Judge, ssSHEENSss and Burweed.

Kimmo Aroluoma is the owner of Custom Boards Finland. He is a veteran guitar tech who has toured for years with Finnish bands HIM, Amorphis, Michael Monroe, The Rasmus and Von Hertzen Brothers. Today he designs pedalboards and runs his own web shop in Helsinki, Finland.

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